3_12 specification for monitoring control and protection of shp stations

8/9/2019 3_12 Specification for Monitoring Control and Protection of SHP Stations

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VERSION 2

STANDARDS / MANUALS / GUIDELINES FORSMALL HYDRO DEVELOPMENT

SPONSOR: MINISTRY OF NEW AND RENEWABLE ENERGY GOVERNMENT OF INDIA

GUIDELINES FOR

MONITORING CONTROL AND PROTECTION OF SHP

STATIONS

LEAD ORGANISATION: ALTERNATE HYDRO ENERGY CENTRE INDIAN INSTITUTE OF TECHNOLOGY, ROORKEE



CONTENTS

ITEMS PAGE NO.

1.0 INTRODUCTION 1

1.1 OBJECTIVE 1

1.2 GENERAL 1

1.3 REFERENCES AND CODES 2

SECTION – I GENERAL TECHNICAL CONSIDERATIONS FOR

PREPARING SPECIFICATIONS

3

1.0 MONITORING OF SHP 3

1.1 SYSTEMS FOR MONITORING 3

1.2 REQUIREMENTS OF MONITORING SYSTEM 5

1.3 LEVELS OF MONITORING 6

1.4 CONTROL OF UNITS OF SMALL HYDROPOWER

PLANT

6

1.5 PROTECTION OF SHP GENERATING UNITS 17

1.6 GENERATOR CONNECTED IN PARALLEL TO

GRID

31

1.7 GENERATORS CONNECTED IN PARALLEL ON

A COMMON BUS

31

1.8 PROTECTION GROUPS 32

1.9 PROTECTION OF POWER TRANSFORMERS 33

1.10 FIRE PROTECTION SYSTEM 33

SECTION – II TECHNICAL SPECIFICATIONS FOR CONTROL,

PROTECTION & METERING ( MICRO HYDEL UPTO

100 KW)

36

2.1 SCOPE 36

2.2 APPLICABLE STANDARDS 36

2.3 DESIGN CRITERIA 36

2.4 PROTECTION AND METERING 37

2.5 TESTS 39

SECTION - III TECHNICAL SPECIFICATIONS

CONTROL, PROTECTION AND METERING(FOR SHP ABOVE 100KW TO 1000KW)

40

3.1 SCOPE 40

3.2 CONTROL EQUIPMENT 40

3.3 SYNCHRONIZATION 40

3.4 ALARM AND ANNUNCIATION 41

3.5 METERING 41



ITEMS PAGE NO.

3.6 PROTECTION RELAYS 41

3.7 UNIT CONTROL BOARD 41

3.8 COMPLETENESS 41

3.9 SPARE PARTS & TOOLS 41

3.10 DOCUMENTATION 42

3.11 STANDARDS 42

3.12 FUNCTIONAL REQUIREMENTS 44

3.13 UNIT CONTROLLERS 44

3.14 PROTECTION AND METERING DETAILS 45

3.15 METERING SYSTEM 47

3.16 UNIT CONTROL BOARD/CONTROL PANEL 483.17 SYNCHRONIZING PANEL 48

3.18 ANNUNCIATION SYSTEM 49

3.19 FACTORY TESTING 50

3.20 SITE TESTING 50

3.21 DRAWINGS 51

3.22 SPARE PARTS & TOOLS 51

SECTION -IV TECHNICAL SPECIFICATION FOR CONTROL

PROTECTION, METERING, SUPERVISORY

CONTROL AND DATA AQUISITION SYSTEM (SCADA)

52

4.0 SCOPE 52

4.1 APPLICABLE STANDARD 52

4.2 CONTROL AND MONITORING SYSTEM 52

4.3 CONTROL AND MONITORING OF PLANT

EQUIPMENT

54

4.4 MANUAL CONTROL, METERING AND

PROTECTION SYSTEM

75

4.5 SUPERVISORY CONTROL AND DATA

ACQUISITION (SCADA) SYSTEM

84

SECTION -V TECHNICAL SPECIFICATION FOR CONTROL

PROTECTION, METERING AND SUPERVISORY CONTROL

AND DATA ACQUISITION SYSTEM

(SCADA)

95

5.0 SCOPE 95

5.1 APPLICABLE STANDARD 95

5.2 CONTROL AND MONITORING SYSTEM 96

5.3 CONTROL AND MONITORING OF PLANT

EQUIPMENT

96

5.4 MANUAL CONTROL, METERING AND

PROTECTION SYSTEM

123



ITEMS PAGE NO.

5.5 SUPERVISORY CONTROL AND DATA

ACQUISITION (SCADA) SYSTEM

138

5.6 COMMUNICATION LINK 147

5.7 FACTORY TESTS FOR UNIT CONTROL

SWITCHBOARDS

150

5.8 FIELD TESTS FOR UNIT CONTROL

SWITCHBOARDS

151

5.9 ADDITIONAL FACTORY AND FIELD TESTS

FOR DISTRIBUTED CONTROL SYSTEMS

151

5.10 DATA/ DOCUMENT TO BE FURNISHED BY THE

BIDDER

152



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GUIDE LINES FOR TECHNICAL SPECIFICTION FOR

MONITORING CONTROL AND PROTECTION OF SHP STATIONS

1.0 INTRODUCTION

1.1 OBJECTIVES

This guide is intended to assist in preparation of specification for monitoring of

various parameters of various operations, control and protection of main generating

equipment viz turbine, generator, transformer and other associated auxiliaries.

1.2 GENERAL

The generating units of a small hydropower plant may have its shaft vertical,

horizontal or inclined with the type of turbine selected to suit the site’s physical conditions.Small hydro turbines may be selected as per site conditions, head and discharge available.

Small hydro-generator are of the alternating current type and may be either synchronous or

induction type. Usually small hydro units up to 5 MW are expected to require minimum

amount of field assembly and installation work. While machine having capacity from 5 MW

to 25 MW may have slow speed, large diameter and with split generator stator that require

final winding assembly in the field.

Mini & micro power stations are generally provided system suiting to these being run

unattended or with few attendants while bigger machines up to 5 MW capacity have more

elaborate arrangement of control monitoring and protection. Machine having capacity up to

25 MW and provision of parallel operation with other systems will have more comprehensivecontrol, monitoring & protection system.

This guide, therefore, describes control, monitoring and protection requirement of

small hydro power plants in following categories:

Section-I General technical considerations for preparing

specifications

Section- II Technical Specification for MHP having capacity

upto100KW,

Section-III Technical Specification for SHP having capacity

above 100KW to1000KW,

Section-IV Technical Specification for SHP having capacityabove 1MW to 5 MW

Section -V Technical Specification for SHP having capacity

above 5MW to 25 MW.

This guide will serve as a reference document along with available national &

international codes standards, guide & books. For the purpose of convenience Section-I of

this guide has been subdivided as follows

• Monitoring

•

Control• Protection



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1.3 REFERENCES AND CODES

IEEE Std 1020 - IEEE guide for control of small hydro electric power

plants

IEEE Std 1010 - IEEE guide for control of hydro electric power plants

IEEE Std 60545:1976 - Guide for commissioning operation and maintenance of

Hydraulic Turbines

IEC 61116:1992 - Electro mechanical guide for small hydroelectric

installations

IEEE std 1046 - IEEE application guide for distributed digital control

and monitoring for power plants

IEEE std. 1249 - IEEE guide for computer–based control for power

plant automationIEEE std. C 37101 - IEEE guide for generator ground protection

IEEE std. C 5012 - IEEE standard for salient pole 50 Hz and 60 Hz

synchronous generator and generator / motors for

hydraulic turbine application rated 5 MVA and above

IEEE std 4214 - IEEE guide for preparation of excitation system

specification

ANSI/ IEEE std 242:1996 - IEEE recommended practice for protection and

coordination of industrial and commercial power

systems

ANSI/ IEEE std C 372-1987 - IEEE standard electrical power systems device function

numbers

ANSI/ IEEE std C 37.95 : 1974 - (R1980) IEEE guide for protective relaying of utility

ANSI/ IEEE std C 37.102:1987 - IEEE guide for generator protection

MASON, CR - Art & science of protective relaying 1956

AHEC/PFC/FINAL REPORT 2002



3

SECTION – I

GENERAL TECHNICAL CONSIDERATIONS

FOR PREPARING SPECIFICATIONS

1.0 MONITORING OF SHP

Monitoring of operating parameters of the generating unit and their auxiliaries is very

important for the life and optimum utilization of available discharge for generation. The

efficient running of unit require regular monitoring. The primary input data and generation

output data are monitored periodically. The details of data required for monitoring

performance of a generating station is as following.

1.1 SYSTEMS FOR MONITORING

1.1.1 Water Conductor System

• Storage level at dam / barrage / weir

• River discharge

• Headrace channel discharge

• Discharge at outlet of disilting basin

• Forebay level

• Discharge of spillway

• Penstock pressure

• Tail water level

1.1.2 Hydro-mechanical Parameters

• Turbine and accessories

o Pressure and levels in oil pressure system

o Bearing temperatures (oil & pads)

o Oil level in bearing sumps (if provided)

o Cooling water pressure and temperatures

o Clean water pressure for shaft gland

o Vibration in shaft for large machines

o Status of inlet and other valves.

• Generator and accessorieso Stator winding temperature

o Rotor winding temperature

o DE/NDE end bearing temperatures

o Cooling water and air temperatures

o Air gap monitoring

• Transformers

o Winding temperature

o Oil temperature

o Oil level

o

Cooling water temperature and pressures



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1.1.3 Electro-mechanical Operating Parameters

• Turbine & accessories

o Speed

o Guide vane opening & limits (precent)

o Runner blade opening in Kaplan Turbine (percent)o Nozzle opening in impulse turbine (percent)

• Generator & auxiliaries

o Governor actuator balance current (Amp)

o Generated power (kW or MW)

o Generated hour (kWh)

o Kilovolt ampere (kVA)

o Kilovolt ampere reactive (kVAR)

o Power factor (PF)

o Frequency (Hz)

o Excitation voltage (Volts)

o Excitation current (Amp)

o Recorder for kW, Hz, kWh etc

• Transformers

o Tap position

o HV/LV current

o Primary/ secondary voltage

• Grid system & transmission line

o Grid voltage

o Grid frequency

o Power export / import (kW)

o

Current (Amp)o Kilowatt hour (kWh) export / import

• Station auxiliaries

o Voltage and current on LT AC system

o Kilowatt hour (kWh)

o Diesel generator running hour, kWh & other parameters

o Drainage & dewatering system

Running hours of pumps

Water level in sump

o Fire extinguisher – periodical testing

o Battery set- Regular monitoring as per manufacturers recommendations

o Battery chargers & distribution boards – voltage current etc.o Air compressors – HP /LP pressures and running hours

o OPU system

Running hours of pumps

Level in pressure accumulators

Pressure of oil



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1.2 REQUIREMENTS OF MONITORING SYSTEM

1.2.1 Instrument Transformers & Sensors

CTs & VTs

Current and voltage transformers of rated voltage and appropriate ratio, class of accuracy is selected as per the requirement of the system.

Sensors

The sensors for temperatures, pressures, levels speed are installed at the proper

location.

1.2.2 Indicating Meters

Analogue type of meters, separate for each parameter with selector switches etc were

being used earlier installed on control panels. Now a days digital meters are being used forsuch parameters. Digital multifunction meters are now in use, only one meter provides

several parameters an selection, as well as provides routine display. Few analogue meters like

power meters (kW), voltmeters, ameters with selector switches are provided for operational

facilities.

1.2.3 Temperature Scanners

Digital temperature scanners indicating the temperatures of stator winding, bearing

pads, oil coolers etc. are provided and installed on the generator control panels. These

scanners get the signals from the sensor installed at specific location preferably through

screened cables.

1.2.4 Indicating Lamps

Indicating lamps of suitable colours as per code and practices should be provided on

control panels for indication status of machine and various auxiliaries, pumps, electrical

equipment like breaker, isolator, AC/DC supply system etc. Lists of such indication and

relays are enclosed as Annexure-I&II.

1.2.5 Alarm & Annunciations

The protection system relays and auxiliary relays also provided signals to alarm and

annunciation system. A set of annunciation windows are provided on control panels for each

fault clearing relay with accept test and reset facility through push buttons. Alarm and trip

annunciation indicate the fault and advise operating personnel of the changed operating

conditions.

1.2.6 PLC Based System

Recently control of machine and auxiliaries is done through PLC based controlsystem automatically in addition to manual systems with local and remote facilities. The data



6

are acquired through sensors and operation of machine is achieved on present values through

PC Monitors etc.

The PLC will acquire data from generating units, transformers, switchgears auxiliaries

through transducers / sensors/ CTs/ VTs wherever signals are week, noise level is high

shielded cables should be used for carrying data / signals. For sending output signal PLC willuse relays for operating breakers etc and comparators for giving ON/OFF signal.

1.3 LEVELS OF MONITORING

Normally two levels of monitoring is provided in SHP as per recommendation of IEC

1116. The levels are:

• Alarm

• Tripping

In case of manned power plant ‘alarm’ comes first so as to make the operator alert if

no corrective action is possible then tripping command with indication / hooter and

annunciation will be there.

But in case of unattended power plant direct tripping command will be initiated and

shut off the facility to avert possibility of any damage to the plant.

1.4 CONTROL OF UNITS OF SMALL HYDROPOWER PLANT

1.4.1 GENERAL

For small hydro installation simplicity of control system is advised, however, thesophistication of control should be based on the complexity and size of the installation,

without compromising unit dependability and personal safety. Simplicity of control is

desirable to keep total cost of installed equipment as well as cost of maintenance, repair and

tests at economical level. Moreover a simpler system is more reliable as compared to

complex one.

1.4.2 GENERATOR CONNECTION TO SYSTEMS

1.4.2.1 Synchronous Generator

For conventional method of synchronizing the generator is started, accelerated to near

synchronous speed and excitation is applied. The voltage and the frequency are matched andunit is synchronized to the system, by closing generator circuit breaker or contactor, when

done perfectly no current surge will occur. Normally both manual and automatic

synchronizing of generator are provided. In addition the speed of some types of turbines

under no load conditions is so sensitive to small adjustments in runner blade angle or inflow

as to make only automatic synchronizing practical.

Small hydropower plants will certainly require unattended automatic synchronizing.

Manual synchronizing necessitates availability of continuous display of voltage, frequency,

phase angle and devices to control voltage and speed on the control panel.

Transducers or signal transmitters are provided either at the control panel or at theequipment.



7

1.4.2.2 Induction Generator

For conventional method of connecting induction generator to the grid, the generator

is started and accelerated to synchronous speed. In fact, the rotor speed of generator shall be

(1% slip) more than grid frequency. This is done to avoid monitoring action of generator.Once the generator frequency matches with grid frequency the generator breaker is closed.

Now the generator is connected with the grid and running at no load.

At this stage grid power factor is to be checked and capacitor banks are switched on

as per requirement to provide necessary reactive power and further loading of unit is done

upto full load.

All these functions can be performed manually as well as automatically through PLC,

computer, microprocessor based control system.

For smaller machines which are unattended provision of integrated digital control &SCADA system is preferred.

1.4.2.3 Status and Alarm Requirements

• Unit ready to start

• Breaker position (no alarm if manual operation only)

• Intrusion alarm

• Fire alarm

• Emergency status alarm (requires immediate attention0

• General status alarm (response can be differed)• Trash rack differential alarm

• Unit stopped (when not required)

• Unit turning (when not required)

• High bearing temperatures

• Loss of lubrication or cooling or both

• Low hydraulic system pressure

• Incomplete start or stop sequence

• Loss of power

1.4.3 UNIT CONTROL

The control logic system for small hydro start stop sequencing can be provided by

hardwired relay logic, programmable controllers microprocessor based systems or a

combination of these.

The unit control system should be designed to perform following functions:

• Data gathering and monitoring

• Start stop control sequence

• Annunciation & alarm conditions

• Temperature monitoring• Metering & instrumentation



8

• Event recording

• Synchronizing and connecting the unit to grid

• Control of real & reactive power

The unit control system must be able to provide startup and shutdown sequencing

under both normal and abnormal conditions. Under normal conditions, the unit is started andstopped in manner that produces minimal disturbance to the system. For instance of normal

stop sequence entails a controlled unloading of machine and when completely unloaded, the

generator breakers or contactor is tripped. On the other hand protective relay operation will

initiate immediate tripping of the unit and complete shutdown as quickly as possible.

For certain mechanical troubles the unit is unloaded as quickly as possible before

tripping, in order that the potential damage from over speed is avoided.

The unit control system, in order to control and monitor various control sequences,

must interface with number of plant systems, including the following:

• Auxiliary system – pumps & valves

• Governor load control rollers – setters, solenoids & brake control

• Excitation – setters, contactors and circuit breakers

Typical startup and shutdown sequence are shown in fig. 1-3 for a Francis turbine

unit, which, for the sake of illustration, are shown as including synchronous generator and

governing system.



9

Fig. 1: Typical Start Sequence of Synchronous Generator



10

Fig. 2: Typical Normal Shut Down and Mechanical Trouble Stop Sequence of

Synchronous Generator



11

Fig. 3: Typical Electrical Trouble Stop Sequence for Synchronous Generator

1.4.4 CONTROL FUNCTIONS

There are many functions to be controlled in a small hydropower system. For example

turbine governor controls the speed of turbine, plant automation covers operations as auto

start, auto synchronization, remote control startup or water level control and data acquisition

and retrieval covers such operation as relaying plant operating status, instantaneous system

efficiency or monthly plant factor.

1.4.4.1 Turbine Control

This is the speed / load control of turbine in which governor adjusts the flow of water

through turbine to balance the input power with load.



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In case small plants in the category of micro hydel (100 kW unit size), load

controllers are used, where excess load is diverted to dummy load to maintain constant speed.

With an isolated system, the governor controls the frequency of the system.

In interconnected system, the governor may be used to regulate unit load and maycontribute to the system frequency control. Figure 4 shows the different types of control

applicable to turbines.

Fig. 4: Turbine Control

1.4.4.2 Generator Control

This is the excitation control of synchronous generator. The excitation is an integral

part of synchronous generator which is used to regulate operation of generator. The main

functions of excitation system of a synchronous generator are:

• Voltage control in case of isolated operation and synchronizing• Reactive power or power factor controls in case of inter connected operation.

The different generator controls are shown in fig. 5.

Fig. 5: Generator Controls

1.4.4.3 Plant Control

Plant control deals with the operation of plant. It includes sequential operation like

startup, excitation control, synchronization, loading unit under specified conditions, normal

shutdown, emergency shutdown etc. The mode of control may be manual or automatic and



13

may be controlled locally or from remote location. Plant control usually include monitoring

and display of plant conditions. Different plant controls are given in fig 6.

Fig. 6: Overview of Plant Automatic Control

1.4.5 CONTROL OF HYDROELECTRIC POWER PLANTS

1.4.5.1 Vertical Array of Control System

For hydroelectric power plants the components of the control system can be shown in

vertical array as shown in fig 7.

Fig. 7: Hierarchy of Controls of Hydropower Plants



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• At lowest level (process level) process which includes, generator exciter, turbines,

switchgears, motors, pumps, valve etc is being controlled.

• At middle level there is control interface equipment which sends signals to the

apparatus from controlling equipment and for apparatus to transmit data back to

controlling equipment. Auxiliary contacts of motor starter, relays instrument

transformer signal conditioner, transducers or other interface devices.• At top level there is controlling system which initiates control signals and receives the

data transmitted from apparatus control interface equipment. At this level itself

human-machine interface is included.

1.4.5.2 Categorization of Control System

The control system can further be defined by identifying following three categories of

control:

• Location:

a. Local - control is local at the controlled equipment within the sight of

the equipment

b. Centralised - control is at other place, but within the plant

c. Off site - control is at remote place which may be quite far from the

plant (Remote)

• Control mode:

a. Manual - Each operation requires a separate and distinct initiation.

However it may be applicable for any of the three locations

b. Automatic - With single initiation several operations in appropriate

(PLC/ computer/ sequence are done. This system can also be applicable to any

Microprocessor of the above three locationsControlled)

• Operation (supervision)

a. Attended - Operators are all the time available at the plant to perform

control action either locally or centralized control

b. Unattended - Operating staff is not available at the plant. There may be

occasional visits by operation & maintenance people to ensure

security of plant.

1.4.5.3 Information and Control Signals

Following four types of signals are provided between control board and particularequipment

• Analog inputs for variable signals from CTs, VTs, RTDs, pressure, flow, level,

vibration etc.

• Digital inputs provides digitalized values of variable quantities from the equipment

• Digital outputs – command signals from control boards to equipment

• Analog outputs – transmit variable signals from control to equipment e.g. governor,

voltage regulator etc.



15

1.4.5.4 Communication Links

a. Communication links with remote control

Following methods are available for implementing control from a remote location:

• Hardwired communication circuits (telephone type line, optical cables etc.)• Leased telephone lines

• Power line carries communication system

• Point to point radio

• Microwave radio

• Satellite

Metallic circuit in hardwire communication circuits and leased telephone lines,

requires special protection for equipments and personals against ground potential rise (GPR)

due to electric system fault, since the hydro-generator is source of fault current. GPR is also

caused by lightening transmitted through power lines entering the power plant. As suchsuitable mitigation has to be provided.

Power line carrier including insulated ground wire system can be used for

communications purposes. This method couples a high frequency signal on the power line or

insulated ground wire and is decoupled at an offsite point.

Space radio can be used, utilizing power frequencies and micro wave radio can be

practical if hydro plant owner has an existing microwave system.

b. Communication with control boards

Data and control signals of following equipments will be required to be transmitted

between control board & equipments.

• Generator neutral and terminal equipment

• Head water and tail water level equipment

• Water passage shut off or bye pass valves gates etc.

• Turbine

• Unit transformer

• Circuits breaker and switches

• Generator

• Intake gates or main inlet valve and draft tube gates

• Turbine governing system

• Generator excitation system

The communication link between control board and equipment should be reliable.

c. Communications with Auxiliaries

Data and control signals of following auxiliaries/ equipments will be required to be

transmitted between control board and equipments.



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• Fire protection

• AC Power supply

• DC Power supply

• Service water

• Service air

• Water level monitoring

• Turbine flow monitoring

1.4.6 MODERN PRACTICE REGARDING GOVERNOR AND PLANT CONTROL

1.4.6.1 Previous Practice

Control of a hydro plant generating unit was typically performed from central control

board located in centralize control room. The control board contained.

• Iron vane meters

• Hardwired control switches• A large number of auxiliary relays to perform unit start / stop operations

• All the sensors and controls required to operate unit or units were hardwired to control

panels allowing control of power station from cotnralised control room

1.4.6.2 Modern Practice

Modern digital integrated control and protection system including programmable

logistic controller (PLCs), distributed computer control system or personal computer control

system not only provide supervisory control and data acquisition (SCADA) but also

flexibility in control, alarm, sequencing, remote communication in a cost effective manner

and has been specifically recommended for SHPs in India, under UNDP – GEF projects.

Control functions of small hydro plants are standardized in following US standards

a. IEEE guide for control of small hydro electric plants, “ANSI/IEEE standard 1011,

1990’.

b. IEEE guide for control of hydroelectric power plants “ANSI/IEEE standard 1010,

1991.

Specific hardware or software to be utilized for implementation is not however

addressed in these standards.

Architecture and communication are two potential problem area for computerized

control system.

In 1990, the International Organisation for standardistion developed a model for open

architecture and protocol, know as SI (open system interconnection) – ISO mode.

Programmable Logic Controllers (PLC) type plant controllers combine with PC based

SCADA systems are used as Governors and for plant control & data acquisition. This makes

the system less costly and reliable and therefore, can be used for small hydropower

generation control.



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Personal computer based dedicated digital control system can perform all functions of

governing, unit control, protection and also data acquisition & storage and are more

economical and reliable. These dedicated systems with back up manual control facility of

turbine control in emergency by dedicated semi automatic digital controllers can be a low

cost option for small hydropower station.

1.5 PROTECTION OF SHP GENERATING UNITS

1.5.1 GENERAL

Small hydro turbine-generators should be protected against mechanical, electrical,

hydraulic and thermal damage that may occur as a result of abnormal conditions in the plant

or in the utility system to which the plant is electrically connected.

The abnormal operating conditions that may arise should be detected automatically

and corrective action taken in a timely fashion to minimize the impact. Relays (utilizing

electrical quantities), temperature sensors, pressure or liquid level sensors, and mechanical

contacts operated by centrifugal force, etc., may be utilized in the detection of abnormalconditions. These devices in turn operate other electrical and mechanical devices to isolate

the equipment from the system.

Where programmable controllers are provided for unit control, they can also perform

some of the desired protective functions.

Operating problems with the turbine, generator, or associated auxiliary equipment

require an orderly shutdown of the affected unit while the remaining generating units (if more

than one is in the plant) continue to operate. Alarm indicators could be used to advise

operating personnel of the changed operating conditions.

Loss of individual items of auxiliary equipment may or may not be critical to the

overall operation of the small plant, depending upon the extent of redundancy provided in the

auxiliary systems. Many auxiliary equipment problems may necessitate loss of generation

until the abnormal conditions has been determined and corrected by operating or maintenance

staff.

The type and extent of the protection provided will depend upon many considerations,

some of which are: (1) the capacity, number, and type of units in the plant; (2) the type of

power system; (3) interconnecting utility requirements; (4) the owner’s dependence on the

plant for power; (5) manufacturer’s recommendations; (6) equipment capabilities; and (7)control location and extent of monitoring. Overall, though, the design of the protective

systems and equipment is intended to detect abnormal conditions quickly and isolate the

affected equipment as rapidly as possible, so as to minimize the extent of damage and yet

retain the maximum amount of equipment in service.

Small hydroelectric power plants generally contain less complex systems than large

stations, and therefore tend to require less protective equipment. On the other hand, the very

small stations should be typically unattended and under automatic control, and frequently

have little control and data monitoring at an off-site location. This greater isolation tends to

increase the protection demands of the smaller plants.



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An inherent part of the power plant protection is the design of the automatic controls

to recognize and act on abnormal conditions or control failures during startup. Close

coordination of the unit controls and other protection is essential.

1.5.2 EQUIPMENT TROUBLE

1.5.2.1 Plant Mechanical Equipment Troubles1.52.1.1 Turbines

(a) Excessive vibration

(b) Bearing problems

(c) Over speed

(d) Insufficient water flow

(e) Shear pin failure

(f) Grease system failure

1.5.2.1.2 Hydraulic Control System

(a) Low accumulator oil level

(b) Low accumulator pressure

(c) Electrical, electronic or hydraulic malfunctions within the governing or gate

positioning system

1.5.2.1.3 Water Passage Equipment

(a) Failure of head gate or inlet valve

(b) Head gate inoperative

(c) Trash rack blockage

(d) Water level control malfunction

1.5.2.2 Plant Electrical Equipment Troubles

1.5.2.2.1 Generator

(a) Abnormal electrical conditions

(b) Stator winding high temperature

(c) Low frequency

(d) Bearing problems

(e) Motoring

(f) Fire(g) Excessive vibration

(h) Cooling failure

(i) Over speed

1.5.2.2.2 Main Transformer

(a) Insulation failure

(b) High temperature

(c) Abnormal oil level

(d) Fire



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1.5.2.2.3 Generator Switchgear and Bus

(a) Electrical fault

(b) Mechanical failure

(c) Loss of control power

1.5.2.3 General Plant Troubles

1.5.2.3.1 Station Service

(a) Transformer failure

(b) Unbalanced current

(c) DC System Trouble

(d) Station Air System Trouble

(e) Service Water System Trouble

(f) Flooding

(g) Fire

(h) Unauthorized Entry(i) Protection or Control Logic System Malfunction

(j) Water level Monitoring System Malfunction

1.5.2.4 Utility System Troubles

Utility line faults and other abnormal utility system conditions should be detected and

the plant be disconnected from the utility system. Abnormal utility system conditions include

the following situations:

a. Ground or phase faults

b. Single phasing

c. Abnormal voltage

d. System separation (islanding)

Coordination with the utility is needed in selecting specific protective equipment,

particularly for line fault detection.

1.5.3 DEVICES USED IN A TYPICAL PROTECTION SYSTEM

There are numerous ways of providing the functional protective requirements of the

plant. While standard devices are generally available that can provide the protective functionsrequired, however each station should have specific design suitable for protection

requirements of the power plant equipment as well as the interconnection.

The following section describes components of a typical protection system that might

be applied to a small hydro plant. Discussions and diagrams are included to illustrate location

and arrangement of relays.

1.5.3.1 Protective Devices

1.5.3.1.1 Temperature

A temperature device, possibly incorporating display and contacts for alarmannunciation and tripping to monitor bearing stator and transformer winding temperatures.



20

Resistance temperature devices operating relays can also be used to detect generator stator

overheating.

1.5.3.1.2 Pressure and Level

Pressure and level switches installed in the turbine air and oil systems, to alarm, block startup, or trip, as necessary.

1.5.3.1.3 Over and under speed

Direct-connected or electrically driven speed switches for alarm, control, and tripping.

1.5.3.1.4 Vibration

Vibration detectors monitoring turbine or generator shaft sections, with alarm and trip

contacts.

1.5.3.1.5 Water level

A measuring system incorporating level sensors and monitoring equipment, to alarm,

trip, or control turbine output on limiting values of headwater or tail water level, or head.

1.5.3.1.6 Fire

Sensors located in areas where fire can occur and connected to a central fire monitor

for alarm. Small generators usually do not have fire sensors or suppression equipment, since

they are not usually enclosed.

1.5.3.1.7 Miscellaneous mechanical

Sensing devices are integral to the protected systems, such as automatic greasing

system, wicket gate shear pins, transformer, cooling and station sump drainage system.

1.5.3.2 Protective Relay and Protection System

1.5.3.2.1 Features of relays

The protective relays stand watch and in the event of failures short circuits orabnormal operating conditions help de-energize the unhealthy section of power system and

restrain interference with rest of it and limit damage to equipment and ensure safety of

personals. The protective relays should possess following features:

• Reliability – To ensure correct action even after long period of inactivity and also to

offer repeated operation under sever condition.

• Selectivity – To ensure that only the unhealthy part of system is disconnected

• Sensitivity – Detection of short circuit or abnormal operating condition.

• Speed – To prevent and minimize damage and risk to instability of rotating plant.



21

• Stability – The ability to operate only under those conditions that calls for its

operation and to remain either passive or biased against operation under all other

conditions.

1.5.3.2.2 Type of relays

There are several types of relays being used for protection systems

- Electromagnetic relays

- Static relays

- Numerical relays

The old conventional electromagnetic relays are now being replaced with static relays

with are much faster and maintenance free. These relays are more reliable and sensitive.

These microprocessor based relays have different protections elements and therefore a

separate relay for each protection is not required. A list of protections generally available in

these microprocessor based relays is enclosed as Annexure-II. The numerical relays arehaving LED indications for power ON, trip status for different protection elements, time /

current characteristics selected and contacts for trip signals. However, some individual

electromagnetic conventional / static relays for few important protections are recommended

to be provided as standby relays.

• Advantages of numerical relays

It has been a practice to use electro-mechanical / solid state relays for all above

protections. The present trend is to use numerical relays which offer many advantages as

follows, over the earlier technology.

PARAMETER NUMERIC CONVENTIONAL

Accuracy 1% 5%/7.5%

Burden <0.5 VA >5 VA

Setting Ranges Wide Limited

Multi Functionality Yes No

Size Small Large

Field Programmability Yes No

Parameter Display Yes No

System Flexibility Yes No

Co-ordination Tools Many TwoCommunication Yes No

Remote Control Yes No

Special Algorithms Many Limited

Special Protections Yes No

Self Diagnostics Yes No

The user’s worry that numerical relays are very expensive is now removed due to

continuous production, improvement in techniques which have made numerical relays above

all, with features listed as above. Numerical relays are more user friendly and are gaining

popularity everywhere.

Following annexure are enclosed for ready reference



22

• Annexure-I - List of SHP Generator panel indications & relays

• Annexure-II - List of protection elements in Microprocessor based relays

1.5.3.2.3 Criteria of selection of protection system

The designer must balance the expense of applying a particular relay against the

consequences of losing a generator. The total loss of generator may not be catastrophic if it

represents a small percentage of the investment in an installation. However, the impact on

service reliability and upset to loads supplied must be considered. Damage to equipment and

loss of product in continuous processes can be dominating concern rather than generating

unit. Accordingly there is no standard solution based on MW-rating. However, it is rather

expected that a 500 kW, 415 V hydro machine will have less protection as compared to 25

MW base load hydro electric machine.

With increasing complications in power system, utility regulation, stress on cost

reduction and trends towards automation, generating unit protection has become a high focus

area. State of the art, micro controller based protection schemes offer a range of economical,

efficient and reliable solution to address the basic protection and control requirements

depending upon the size and specific requirement of the plant.

1.5.3.3 Requirements of Protection of Turbine

Two level protection is recommended as per IEC 1116. Elements to be considered

are:

(a) Speed rotation(b) Oil levels in bearing

(c) Circulation of lubricants

(d) Oil level of the governing system

(e) Oil level of speed increaser (if provided)

(f) Bearing temperatures

(g) Oil temperature of governing system

(h) Oil temperatures of speed increasers

(i) Oil pressure of governing system

(j) Pressure of cooling water

Immediate tripping is required for a, c, i, and j. While for item b, d, e, f, g and h onlyalarm and annunciation is required to alert the operator and take corrective action, but in case

corrective action is not taken, tripping will eventually follow. Applying brakes at a particular

speed (30% of full speed) is done to reduce time to achieve stand still position of machine.

It is recommended two independent devices must be provided for over speed shut

down on larger machines. One for alarm mostly at 110% and other for tripping at 140%,

specially for machines which are not designed for continuous run away speed.

1.5.3.4 Requirements of Protection of Generator

Elements to be considered normally are



23

a. Stator temperature

b. Over current (stator and rotor)

c. Earth fault with current limits (stators & rotor)

d. Maximum and minimum voltage

e. Power reversal

f. Over/ under frequencyg. Oil level in bearing sumps

h. Pad & oil temperature of bearings

i. Cooling air temperature

Immediate tripping is required for items b, c, d, e & f while for items a, g, h and i first

alarm and annunciation is required for taking correcting measure and then tripping if

correcting measure is not taken within permissible time.

It is advisable to provide heating arrangement to prevent condensation in generator.

1.5.3.5 Generator Protection System and Relay Selection1.5.3.5.1 Categorisation

In view of the economy and plant requirements generator protection for small

hydropower stations is categorized a follows:

• Generator size less than 300 kVA

• Generator size 300 to 1000 kVA

• Generator size 1 MVA to 10 MVA

• Generator size above 10 MVA

1.5.3.5.2 Transient overvoltage and surge protection

Transient over-voltages and lightning surges are controlled by lightning arrestors.

Surge capacitors are provided to restrict rate of rise of surge voltages and their magnitudes.

Every generator is provided with a set of lightening arrestors / surge diverter of appropriate

rating and generated voltage.

1.5.3.5.3 Minimum protection for a small machine with low resistance grounding are

proposed as follows:

Device No. DescriptionBasic Package

51V Voltage-restrained time over current relay

51GN Neutral ground over current relay

Options

27 Under voltage relay

32 Reverse power relay

40 Loss of excitation relay

46 Negative phase sequence relay

49R Stator over temperature relay

50GS Ground sensor over current relay51VC Voltage controlled over current relay



24

64B Generator ground over voltage relay (in place of 51GN

where generator is ungrounded)

81 L/H Under / over frequency relay

86G Lockout auxiliary relay

87G Self-balancing current differential relay

12 Over speed relay

7.3.5.4 Minimum protection for a large machine with high resistance grounding

Basic Package

21 Distance

24 Over excitation

27 Under voltage

27TN Third harmonic under voltage

32 Reverse power

40 Loss-of-excitation

46 Current unbalance (negative sequence)

51GN Ground over current (backup to 64G)

51V Voltage-restrained over current

59 Over voltage

60V VT fuse failure detection

64G Stator ground

64F Ground (field)-I81L/H Under/ Over frequency



25

87G Percentage differential

50/27 Accidental energisation protection

95 Trip circuit monitoring

86G Lockout auxiliary relay

12 Over speed relay

Options

21G System backup distance relay (in place of 51V)

49R Stator over temperature relay (RTD)

60V2 Voltage ground relay-II

78 Out-off step relay

1.5.3.5.5 Typical schemes

With increasing complications in the power system, utility regulations, stress on cost

reduction and trend towards automation, generator protection has become a high focus area.

State of the art, microcontroller based protection schemes from various manufactures offer a

range of solutions to customers to address the basic protection and control requirements

depending upon the size and plant requirements.



26

1.5.3.5.6 Generators-size less than 300 kVA

Normally these generators are controlled by MCCBs, which offer O/C and short

circuit protections. It is advisable to have following protections in addition to MCCB.

E/F protection (51 N): This will protect the generator from hazardous leakages and

ensure operator safety. Many organizations have already made E/F protection as mandatory.

Since these units are very remotely located and less manpower is available for operation and

maintenance, the system needs more automation and fool proof protections. Therefore,recently several optional protections are also being used for micro/mini units including over

speed (12) protections.

1.5.3.5.7 Generators – size 300 to 1000 kVA

There are two major differences when compared with the small machines considered

above.

• IDMT over current + E/F relay will be required in addition to normal MCCB or ACB

releases – since the generator may need shorter trip time for faults in the range 100%

to 400% level.



27

• By virtue or larger power level, any faults inside the stator or fault between the neutral

of the machine and the breaker terminals can reach very high intensity.

Such internal faults must be cleared instantaneously. Normal IDMT over current E/F

relays are not adequate to monitor this internal fault status-otherwise the machine can

circulate very high fault currents resulting in severe damage.

A high impedance differential relay scheme, is the best suited for this purpose. If theneutral is formed inside the machine, the differential relay scheme will not be

possible. In this case a restricted E/F scheme is the solution. Care should be taken to

provide adequate number of CTs.

• Machine of this size are likely to have external controls for frequency and excitation –

so that they can be run in parallel with other power sources (other generators on the

same bus or the local grid). This necessitates voltage and frequency related

protections as well.

1.5.3.5.8 Generators – size 1 MVA to 10 MVA

• Stator side protections

o Voltage restrained over current protection (50V/51V)

Normal IDMT O/C will not work here-when an over current fault occurs, due

to higher current levels, there would be a drop in terminal voltage. For the

same fault impedance, the fault current will reduce (with respect to terminal

voltage) to a level below the pickup setting. Consequently normal IDMT may

not pick up. It is necessary to have a relay whose pick up setting will

automatically reduce in proportion to terminal voltage. Hence the over current

protection must be voltage restrained. Two levels of over current protection

are required – low set and high set (for short circuit protection).

o Thermal overload (49)

This protection is a must – it monitors the thermal status of machine for

currents between 105% to the low set O/C level (Normally 150%)

o Current unbalance (46)

Generators are expected to feed unbalanced loads-whose level has to be

monitored. If the unbalance exceeds 20%, it may cause over heating of the

windings. This heating will not be detected by the thermal overload relay-

since the phase currents will be well within limits. A two level monitoring for

unbalance is preferred-first level for alarm and the second level for trip.

o Loss of excitation (40)

When excitation is lost in a running generator, it will draw reactive power

from the bus and get over heated. This condition is detected from the stator

side CT inputs – by monitoring the internal impedance level & position of the

generator.

o Reverse Power (32)

Generators for this size may operate in parallel with other sources, which may

cause reverse power flow at certain times.

- During synchronization

- PF change due to load/ grid fluctuations- Prime mover failure



28

When reverse power happens, the generator along with prime mover will

undergo violent mechanical shock – hence reverse power protection is

necessary.

o Under Power (37)

It may not be economical to run generators below a certain load level. Thisprotection will monitor the forward power delivered by the machine and give

alarm when the level goes below a set point. This may however be optional.

o Under/ over voltage (27/59)

This will protect the machine from abnormal voltage levels, particularly

during synchronization and load throw off conditions.

o Under/ over frequency (81)

This will protect the machine from abnormal frequency levels, particularly

during synchronization and load throw off conditions. This will also help in

load shedding schemes for the generator.

o Breaker failure protection

This protection detects the failure of breaker to open after receipt of trip

signal. Another trip contact is generated under breaker fail conditions, with

which more drastic measures can be taken, like opening of bus coupler or

feeder breaker etc.

o Stator earth fault (64F)

This element tuned to the fundamental frequency can be used for the

protection of stator winding from earth fault.

o PT Fuse failure protection

This relay will detect any blowing of PT secondary fuse and give a contact

which can be used to lock the under voltage trip.

This protection is very impartment since the machines of this size have to be

protected for severe damages that may occur due to internal faults.

Considering the large power levels, it is necessary to have a percentage biased,

low impedance differential relay. These relays generally have following

advantages.

- Percentage biased differential protection with dual slope characteristics

- REF protection element (87 N), which will monitor the generator for

internal earth faults

- Over current protection, as a back up



29

• Rotor side protections

Generators of this size will need rotor side protections listed below:

o Diode failure relay

Brushless excitation systems will have rotor mounted diodes, which can

become short or open during operation. Diode failure relay will monitor the

condition of these diodes, for both open circuit and short, and give alarm

o Rotor excitation currentThis is a DC current relay which will monitor the excitation current.

o Rotor excitation voltage

This is a DC voltage relay which will monitor rotor voltage

The above three protections are normally part of the excitation system of the

generator.

o Rotor earth fault

Relay for this protection will monitor the rotor winding status for the earth

fault, it will detect the first earth fault occurred in the winding and provide an

alarm. The relay employs proven DC rejection method for the detection of

E/F. there are other two methods as shown in the diagram for field ground

detection.



30

EXCITER

FIELDBREAKER

AC

RR

64F

BRUSH

FIELD

C1 C2

Fig. 13 Field ground detection using pilot brushes

1.5.3.5.9 Generator above 10 MVA

For large generators above 10 MVA size, the philosophy of main protection and back

up protection has to be followed. In addition to the protections listed above following extra

protections are to be considered.



31

o 100% earth fault protection

This will help in sensing earth faults close to neutral. Third harmonic content

in the zero sequence voltage will be detected by the replay for the above

protection.

o Inadvertent breaker closureThis will avoid closing of generator to bus during process to stop, or when

stand still or before synchronism.

o Under impedance

This will be required as a backup protection for the whole system including

the generator transformer and the associated transmission line. If the distance

relay fails to pick for some reason, this under impedance function will pick up

and save the generator.

o Over excitation

This will protection the generator from over fluxing conditions

1.6 GENERATOR CONNECTED IN PARALLEL TO GRID

Whenever generators are running parallel to grid, a comprehensive auto

synchronizing & Grid islanding scheme will be required. This scheme will help in

synchronizing the generator to the bus and opening the incomer breaker of the plant

whenever there is a severe grid disturbance, thus protecting the generator from ill effects of

disturbed grid.

• Grid disturbances

Under-voltage / Over-voltages

Under-frequency/Over-frequency

Rapid fall/ rise of frequency (df / dt),

Grid failure or other faults

Generator may not be able to operate below a certain power-factor. At low power-

factor, reverse reactive power flow may damage the generator.

• Grid fault detection

Over current and directional earth fault,

Rapid fall/ rise of frequency (df/dt), Vector surge relay,

1.7 GENERATORS CONNECTED IN PARALLEL ON A COMMON BUS

Whenever more than one generator is operating in parallel, it is necessary to see that

the plant load is equally shared by the generators in parallel. If there is unequal sharing, there

would be sever hunting amongst the generators and eventually this will lead to cascaded

tripping of all generators, causing a total black out. Specific load sharing relays are available

in the market which provide the most effective, online load sharing system for generators in

parallel.



32

1.8 PROTECTION GROUPS

The protective relays and devices of generator and turbine are proposed to be grouped

into following four categories for an orderly shutdown of the affected unit with the remaining

generating units and auxiliaries continue to operate.

1.8.1 CONTROLLED ACTION SHUT DOWN

Controlled action shutdown will be initiated by any of the following conditions

• Generator thrust bearing pads temperature very high

• Generator guide bearing pads temperature very high

• Turbine guide bearing pads temperature very high

• Governor OPU oil level low stage-II

• Governor OPU oil pressure low stage-II

1.8.2 EMERGENCY SHUT DOWN

Emergency shutdown will be initiated by any of the following conditions.

• Sped 115% and deflector/ guide vanes/ runner blades apparatus not moved to closing

• Deflector etc. fails to close in preset time

• Unit over speed (electrical) > 140%

• Unit over speed (mechanical)>150%

• Stop push button on control panel in control room is pressed

Emergency shutdown system will perform following functions:

• Trip generator breaker

• Stop turbine by governor action

• Trip generator field circuit breaker

• Operate trip alarm in control room

• Energizes emergency solenoid valve in governor cubicle to stop the turbine by

bypassing governor

• Close main inlet valve

1.8.3 IMMEDIATE ACTION SHUT DOWN

Immediate action shut down will be initiated by any of the following conditions

• Generator differential protection operates

• Generator stator earth fault protection operates

• Generator field failure protection operates

• Generator transformer stand by earth fault protection operates

• Over current in stator

• Over current instantaneous protection in the excitation circuit

The immediate action shut down perform following function



33

Trip generator breaker

Trip field breaker

Initiates controlled action shut down stop turbine by governor action

Trip annunciation in control room

1.8.4 ELECTRICAL SHUT DOWN

Electrical shutdown system will be initiated by any of the following conditions

• Over current in the excitation circuit

• Generator back up protection operates

• Generator over voltage protection operates

• Excitation failure protection operates

• Reverse power protection operates

• Generator T/F IDMT over current, over current instantaneous & earth fault protection

operates

Electrical shut down system will perform following functions

• Trip generator breaker

• Trip field breaker

• Governor brings the unit to spin at no load

1.9 PROTECTION OF POWER TRANSFORMERS

Following protections are generally provided on transformers

I. Fuses

II. Sudden pressure protection (Buchholtz Relay)

III. Oil temperature high

IV. Winding temperature high

V. Over current/ earth fault

VI. Over frequency

VII. Differential protection

VIII. Restricted earth fault protection

IX. Over flux protection (in large grid)

X. Over all differential protection (Gen. Trans. Both in large machines)

XI. Fire protection system Fire extinguishers

Mulsyfire protection

Fire buckets-sand filled

1.10 FIRE PROTECTION SYSTEM

For large generators, fire protections system will use CO2 as the quenching medium

which will operate automatically. Hot spot/ smoke detectors are provided all around the

periphery of generator winding. Bank of CO2 cylinders with control panel etc. are provided

common for all the generators. The individual pipes let the CO2 enter in the faulty generator

and quench the fire. Generator is isolator from the bus bar and machine stopped. The system

is more effective in closed cycle cooling systems of generators.



34

ANNEXURE-I

LIST OF GENERATOR PANEL INDICATION AND RELAYS

Sl.No.

Designation Inscription Colours

1 L1 DC Supply on Yellow

2 L2 AC Supply on Red

3 L3 Generator Circuit Breaker Close Red

4 L4 Generator Circuit Breaker Open Green

5 L5 Generator Circuit Breaker Trip Amber

6 L6 Generator Circuit Spring Charge Blue

7 L7 Trip Coil Healthy Yellow

8 L8 DC Supply Failed Red

9 L9 Spare Red

10 R R Phase Bus Healthy Red11 Y Y Phase Bus Healthy Yellow

12 B B Phase Bus Healthy Blue

13 IPB Immediate Action Trip Push Button Red

14 PB1 Controlled Action Shut Down Push Button Green

15 PB2 Spare Push Button Red

16 TS Temperature Scanner

17 DMF Digital Multi Function Meter

18 H Hooter Black

19 ANN Annunciator Black

20 T Test Push Button Black

21 A Accept Push Button Yellow

22 R Reset Push Button

23 BAPB Bell Accepted Push Button

24 27 Under Voltage Relay

25 32P Reverse Power Relay

26 51V Voltage Controlled Over Current Relay

27 59 Over Voltage Relay

28 60 PT Fuse Failure Relay

29 64S Stator Earth Fault Relay

30 46 Negative Phase Sequence Relay

31 40 Loss of Field Relay32 95 Trip coil Supervision relay

33 87G Generator Differential Relay

34 52G Generator Circuit Breaker

35 KWTR Kilowatt Transducer

36 BL Electrical Bell

37 86G1 Master Trip Relay




41 Aux Relays As Required



35

ANNEXURE-II

LIST OF PROTECTION ELEMENTS IN MICRO PROCESSOR BASED RELAYS

Symbol Description

21 Under Impedance24 Over Fluxing

26 Field Winding Temp

27 Under Voltage

27NT 100% Stator E/F

32 Reverse Power

38 Bearing Temp

40 Loss of Field

46 Negative Phase Sequence

49 Stator Winding Temp

50BF Breaker Failure

50P Instantaneous Phase Over Current50N Instantaneous Neutral Over Current

50/27 Unintentional Energisation at Stand Still

51P Time Delayed Phase Over Current

51N Time Delayed Neutral Over Current

51N Voltage Controlled Over Current

59 Over Voltage

59N Residual Over Voltage

64R Restricted E/F

78 Pole Slipping Protection

81 Over/ Under Frequency

87G Generator Differential

CTS Current Transformer Supervision

VTS Voltage Transformer Supervision



36

SECTION II

TECHNICAL SPECIFICATIONS FOR

CONTROL, PROTECTION & METERING

( MICRO HYDEL UPTO 100 KW)

2.1. Scope

The scope includes design, manufacture, shop testing, delivery erection, testing,

commissioning and training of purchaser personnel for PLC/ computer based

automation system with manual control facility for the operation of power plant from

power house. The scope also includes protection, annunciation, synchronization,

metering and other components for making the system complete and to ensure a

trouble free and safe operation on turnkey basis.

Manual control and manual synchronization shall be provided in addition to

PLC/computer based auto control and auto synchronization

.

For Turbine –Generator unit one Panel shall be provided. The Panel shall incorporate

components for generator protection, indication & alarm devises and meters for

metering various parameters. The requisite functions for ELC can also be

incorporated in this control panel. The Air Circuit Breaker for generator may also be

incorporated in this panel.

2.2.Applicable Standards

(i ) ANSI / IEEE 1010-1987- IEEE Guide for Control of Hydroelectric Power

Plants

(ii) IS/IEC/ISO Standards mentioned in the text

2.3. Design Criteria

The control will have provision for start, stop, manual and auto synchronizing,

protection, metering and emergency stop as per enclosed drawing (to be enclosed by

Purchaser).

Standard control scheme of turbine suitable for micro hydro plants will be adopted.

PLC/computer based controller system will have a dual power unit. The main power

unit will work on 24 V DC and the hot standby power unit will take power from a

UPS at 240 V AC.

Automation system shall have capability to provided diagnostic information in the

event something fails to operation during the start sequence/running.

All the protective equipment will be housed in the Power Plant main control room.

The details of C.T.’s for all the units protection and metering shall be subject to

approval by purchaser.



37

2.4. PROTECTION AND METERING

Electrical control, protection and metering system will be based on state of arttechnologies. PLC based automation systems for the operation of power plant will be

adopted. The complete metering and protection scheme is shown in Drawing (to be

enclosed by Purchaser0. This protection scheme is tentative and is for the general

guidance of the tenderer and does not restrict the tender to give offer for better

scheme.

A. Generator Protections

• Voltage restraint over current (51V)

• Stator earth fault relay (64 S)

• Over speed electrical/Mech. (12)

• Over Voltage Protection (59)

• Under voltage protection (27)

Following Mechanical Protections will be provided on Generator

• RTD (PT-100) in stator core and bearing for indication, alarm,

recording and shutdown of the unit for stator & bearing temp control

• Over speed for normal and emergency shutdown.

B. Metering System

The power generated shall be metered at generator terminal through metering CT and PT.

Following metering instruments shall be provided on relevant panels.

1. kW Meter

2. kWH Meter

3. kV Meter

4. Ampere Meter

5. PF Meter

6. Frequency/Speed Meter7. Temperature Meter for (To be provided only on generator panel)

a. Stator

b. Turbine bearing

c. Generator bearing

C. Annunciation System



38

A multipoint microprocessor based annunciator with suitable number of ways for projecting

visual signals and audible alarm in case of fault shall be provided on the control panels

suitably. The annunciator shall be back connected flush mounting, dust tight and tropicalised

and shall be complete with audible warning device, and apparatus as required to complete the

annunciator system. It shall be suitable for operation on 24 V.D.C. supply.

D. Indication System

The control panel shall incorporate the visual indication such as Breaker on, Breaker off,

Breaker Trip, B/F Valve open, B/F Valve close, D.C on, D.C. off etc. The indication lamps

should be 24 V D.C. operated, interchangeable and replaceable from the front of the panel.

E. Potential Transformers

The potential transformers to be used for metering & protection circuits shall be epoxy cast

resin, class ‘F’ insulation dry type units. The potential transformers shall be protected onprimary and secondary side by current limiting fuses. The potential transformers shall

confirm to the latest Indian standard. IS-3156 (1992)

F. Current Transformers

The current transformers should be suitable for metering & protection circuits shall be epoxy

cast resin, class ‘F’ insulation dry type units. The current transformer will be wound primary

or bar primary as the case may be. The current transformers shall confirm to the latest Indian

standard. IS–2705 (1992)

G. Surge Arrestors

The L.T surge arrestors shall be provided in the control panel. The L.T. surge arrestors shall

confirm to the latest Indian standard.

H. Unit control Board

Following components shall be provided on UCB (the list is tentative). Bidder shall have to

provide additional component, if required for proper operation of unit.

i 415 V --- A Circuit Breaker for generator (MCCB with shunt trip may

be used.)

1 No.

ii Voltmeter 0 – 500V & Voltmeter S/S 1 No.

iii Relays

Voltage restraint over current (51V)

Stator earth fault relay (64 S)

Over speed electrical/Mech. (12)

Over Voltage Protection (59)

Under voltage protection (27)

iv Other meters, switches and alarms

1 No. Each



39

Ammeter (0-50 A) & Ammeter Selector Switch 1 No.

Kilo-Wattmeter ( 0-30 kW) 1 No.

Energy Meter (kWH meter), 1 No.

Indication Lamps Generator Breaker OFF/ON/TRIP 3 No.

Indication Lamps D.C.ON / OFF ( if provided) 2 Nos.

Indication Lamps for B/F Valve open/close 2 Nos.Potential Transformer for protection, metering and AVR 3 Nos.

Current Transformers for Protection & Metering 7 Nos.

Frequency meter 45-50-45 HZ 1 No.

Auto manual change over switch

Power Factor meter 1 No.

Emergency Push Button 1 No.

Annunciation Window for faults & Buzzer/alarm 1 No.

Electronic load controller. 1No.

2.5 Tests

Routine and type test certificate of CTs, PTs, LAs, Relays, Metering instruments as per

IS shall be submitted for approval of the purchaser.



40

SECTION - III

TECHNICAL SPECIFICATIONS

CONTROL, PROTECTION AND METERING(FOR SHP ABOVE 100KW TO 1000KW)

3.1 SCOPE

The scope includes design, manufacture, shop testing, delivery, erection, testing,

commissioning and training of purchasers’ personnel for computer based automation systems

for the operation of power plant from powerhouse. The scope also includes protection,

annunciation and synchronization, metering and other components for making the system

complete and to ensure a trouble free and safe operation on turn key basis. The power

station will comprise the following major components:

i. –x--- kW Synchronous Generating units, Francis Turbine being the

prime mover and synchronized at 415 V, Static excitation and governing

systems being digital.

ii. -- Nos. --- kVA 0.415/11 kV Ynd11 50 Hz 3 phase transformers.

iii. -- Nos. 11 kV feeders controlled by 11 kV vacuum circuit breakers.

iv. 1 No. --- kVA 11KV/0.415 kV Station Transformer and --- kW Diesel

set for station supplies

Following drawings show tentatively the main scheme (to be supplied by the

Purchaser) :

Single Line Diagram

Metering and Protection System

3.2 CONTROL EQUIPMENT

The control equipment shall comprise of the following:

Generating Units Control i. Local/Manual control of generating units from hard wired control panels.

ii. Automatic control of generating units from unit control boards by PLC based

unit controllers.

3.3 SYNCHRONIZATION

Manual synchronization shall be provided in addition to computer based auto-

synchronization with an appropriate change-over switch on the control panel. A check

synchronizing relay will be provided.



41

3.4 ALARM AND ANNUNCIATION

Window annunciation shall be provided on the unit control board and the same shall

be complete with audio and video alarm system. The system shall be designed to have low

DC power consumption.

3.5 METERING

i. All panel meters shall be digital with at least 2 cm digit size, at least three-and-

a-half digit LED display and accuracy class of 1.0 or better.

ii. Energy metering shall be provided on the 11 kV feeders and generators with

electronic energy meter of an accuracy class of 1.0 or better.

iii. Digital Multi-functions Meter alongwith analogue type three ammeter andvoltmeter with selector switch shall be required for each generator circuit.

3.6 PROTECTION RELAYS

i. Each generator shall be provided with static digital numeric type of relays for

the protection system.

ii. Digital relays shall be provided for the protection of 11 kV feeders and ---

kVA 415 V/11 kV Generator Transformers.

3.7 UNIT CONTROL BOARD

The Unit control board for each unit fitted with necessary devices and appropriately

wired using standard accessories shall be provided. Instruments required for turbine control,

monitoring and protections shall be provided by turbine manufacturer for which close liason

shall be required between different manufactures.

3.8 COMPLETENESS

All such systems/equipment/components/works which are necessary for the

completeness of the system but not mentioned explicitly shall also be a part of the scope of

the contractor.

3.9 SPARE PARTS & TOOLS

The contractor shall ensure supply of the spares for all the offered

equipment/components (at least one module of every type) for use for 5 years and any special

tools & plants, spanners etc. required for site assembly, erection, testing, commissioning,

operation & maintenance of the equipment.



42

3.10 DOCUMENTATION

The contractor shall provide all necessary drawings, diagrams and documentation of

equipment and software. The documentation in original shall also include six hard copies and

one soft copy of the following:

a. Hardware:

The necessary user, reference and service manuals along with the technical

specifications for all the hardware systems/sub-systems shall be supplied by the contractor.

The extent of documentation to be furnished shall be to the satisfaction of the Purchaser.

b. Software:

User and reference manuals related to complete software shall be supplied by the

contractor. The extent of the documentation to be furnished shall be to the satisfaction of the

Purchaser.

3.11 STANDARDS

Standard and codes to which the equipment must conform are given below.

IEEE Std 1249 – 1996 Guide for computer based control of

hydroelectric plant automation

IEEE Std 1020 – 1988 Guide for control of small hydro plant

IEEE Std1010 – 1987 Guide for Control of Hydro Electric

Power Plant

IEEE 2519 Power Quality

IEC 687 Alternating current static watt-hour

meters for active energy

IEC 225 Electric relays



43

IEC 68 Environmental testing

IEC 60255-21-1 Vibration

IEC 60255-21-2 National Electrical Code

IEC 60255-1-3 Earthquake

IEC 801-2/4 Static discharge test

IEC 801-3/3 Electromagnetic fields

IEC 801-4/4 Transient fast burst test

IEC 801-5 Surge withstand test

IEC 801-3 Dielectric tests

EN 5501/COSPR11 Emission, terminal disturbance

EN 55011/CISPR11 Emission, radiation disturbance

IEC 62000-4-6 Electromagnetic fields

IEC 61000-4-3

IEC 61000-4-4 Fast transients/Bursts

IEC 61000-4-5 Surge voltage

IEC 61000-4-11 Voltage dips

IEC 60255-22-1 1MHz Burst disturbance

IEC 68-2-1 & 68-2-2 Temperature

IEC 68-2-30 Humidity

IEC 68-2-6 Vibration of Unpackaged Products

IEC 68-2-27 Shock of Unpackaged Products

ASTM D999-75 Vibration of Packaged products

ASTM D775-80 Shock of Packaged products

IEC 1000-4-2 Electrostatic Discharge Immunity

IEC 1000-4-3 Radiated Electromagnetic Immunity

IEC 1000-4-5 Surge Transient ImmunityIEC 1000-4-4 Electrical Fast Transient/Burst Immunity

IEC 1000-4-6 Conducted Electromagnetic Immunity

CISPR 11 (EN55011) Radiated Emissions

UL94V Flammability and Resistance to

Electrical Ignition



44

3.12 FUNCTIONAL REQUIREMENTS

3.12.1 Automation System and Control Options

Computer-based automation systems shall permit operation of the power plant from

local (Machine hall). Local manual control shall also be provided in the equipment as a

backup.

3.13 UNIT CONTROLLERS

For each generating unit, there will be an independent PLC based unit controller.

Back up manual control shall also be provided for each unit.

Each PLC/computer based controller system will have a dual power unit. The main

power unit will work on 24 V d.c. and the hot-standby power unit will take power from a

UPS at 240 V a.c.

3.13.1 Unit Control

3.13.1.1 Control Functions

The unit controllers will control the generating units individually and shall perform

following functions:

i. Automatic start and synchronization

ii. Automatic stop

iii. Control action shut down

iv. Emergency shut down

v. Governor control

vi. Excitation control (AVR and APFC)

vii. Sequence control

viii. Alarm and annunciation

ix. Input from transducers & sensors

x. Active power control



45

3.13.1.2 Auto Start/Stop

The equipment controlled and monitored during the start/stop sequence will generally

include the following:

a. Main inlet valve;

b. Governor hydraulic oil system; (If provided)

c. Guide Vane limit positions;

d. Guide Vane positions;

e. Cooling water system; (If provided)

f. Excitation equipment;

g. Unit speed;

h. Protective relaying status;

i. Unit alarms;

j. Unit breaker status;

3.13.1.3 Diagnostic Information

Automation system shall have capability to provide diagnostic information in the

event something fails to operate during the start sequence/running.

3.13.1.4 Control Scheme Of Turbine

Standard control scheme of turbine suitable for mini hydro plants will be adopted.

3.13.1.5 Back up Control

Back up control including black start should be provided as per IEEE-1249. The black

start shall be accomplished by providing manual pumping of the oil pressure system.

3.13.1.7 Auxiliary Power

The auxiliary power at 415 V shall be taken from the 415 V generator bus and

15 KW 3φ diesel generating set as shown in drawing No. -----.

3.13.1.7 D.C. Supply

The D.C. power at 24 V for all controls, circuit breakers, relays and meters etc. shall

be obtained from one set of station battery. The battery bank shall have 200 AH capacitytentatively and shall be float and boost charged from rectifier units. Calculations for the

capacity of batteries shall be submitted by the bidder for the consideration of the purchaser.

3.14 PROTECTION AND METERING DETAILS

3.14.1 Protection and Metering Scheme

Requirements of metering and protection/scheme and the function performed by

various relays is indicated in tentative drawing for Protection and Metering System:

All the protective relays will be housed on the unit control board.



46

The final drawings for the protection & metering shall be submitted by the contractor

and will be subject to the approval by the Purchaser.

3.14.2 CTs/VTs

All current and voltage transformers required for protection system of the unit shallhave adequate VA burdens, knee point voltage, saturation factor and characteristics suitable

for the application, and shall be subject to approval of the Owner.

3.14.3 Special Features of Proposed Protection System

i. The protection system shall be built on latest technology and the bidder has to

guarantee for supply of spares for at least 5 years. Moreover, the bidder should

have full range of manufacture of the system offered.

ii. Wide setting ranges with fine setting steps for each protection shall be

available.

iii. The offered system shall have proven record of satisfactory performance for

at least 2 years and in two power stations. Necessary certificates to this effect

shall be a part of the offer.

iv. The protective relays shall preferably be housed in draw out type of cases with

tropical finish.

v. Common tripping relays (each for similar functions) will be provided with

lock-out facilities. All these relays shall have potential free contacts for trip and

alarm purposes and externally hand reset type of flag indicators.vi. The relays shall be static/digital/numeric type.

3.14.4 Generator Protection(electrical)

3.14.4.1 Following generator protection relays shall be provided for each generator:

i. Differential Relays (87)

ii. IDMT over current and instanteous over current in stator (50/51)

iii. Stator earth fault protection (64G)

iv. Phase unbalance Relay (46)

v. Field Failure Relay (40)vi. Reverse Power Relay (32)

vii. Over voltage protection (59)

viii. Under voltage (27)

ix. Over Speed (12)



47

3.14.5 Generator Protection(mechanical)

3.14.5.1 Following mechanical protections shall be provided for each unit.

a. Resistance temperature detectors (Pt-100) in stator core and in the

bearings for indication, alarm and recording. RTD’s are to be provided

by Generator Suppliers (optional, if available in standard generator).b. Turbine and generator bearing, metal and oil temperatures –

alarm/shutdown (optional, if available in standard generator).

c. Governor oil pressure low to block starting and very low for emergency

tripping (If Governor oil pressure unit is provided for governing system)

d. Over speed for normal and emergency shutdown depending upon its

extent.

3.14.6 Generator Transformer

Following static relays shall be provided for Generator Transformer Protection.

i. Over current protection with high set instantaneous on 11 kV side

(50/51).

ii. Stand by earth fault protection (64S) on 11 kV side.

iii. Oil temperature high – alarm/trip (OT).

iv. Winding temperature high- alarm/trip (WT)

v. Bucholz relay – alarm/trip (B).

3.14.7 11 kV Feeder Protection

Static over current and earth fault relay with high set unit shall be provided (50/51,64)

alongwith over/under frequency relay (81) for feeders protection.

3.14.7 Station Transformer

Over current/earth fault protection for this transformer shall be provided on generator

bus side. It is presumed that diesel generator protection shall be provided on control panel of

the set.

3.15 METERING SYSTEM

The power generated shall be metered at generator terminal through metering CTs and

PT. The power transferred to 11 kV feeder shall also be metered through CTs and PT.

Following metering instruments shall be provided on generator control panel and 11

kV vacuum circuit breaker panel for feeders. Digital Multi-functions Meters alongwith

analogue type ammeters and voltmeter shall be provided.

3.15.1 Generator Control Panels

1. kW meter

2. kWh meter

3. Voltmeter with selector switch

4. Ampere meters separate for each phase

5. Power factor meter

6. Frequency meter7. Temperature meter with selector switch



48

3.15.2 11 kV Feeder Panels

1. kW meter

2. kWh meter

3. Voltmeter with selector switch4. Ampere meters with selector switch

5. Power factor meter

6. Frequency meter

3.15.3 Generator Transformer Panel


2. Ampere meters with selector switch

3.15.4 Station Transformer Panel

1. kWh meter


3. Ampere meters with selector switch

3.16 UNIT CONTROL BOARD/CONTROL PANEL

3.16.1 Constructional Features

i. All panels shall be of standard construction, dimensions, materials and sheet

thickness of not less than 2.50 mm.

ii. Panels shall be of simplex types (devices mounted on the front panel and

double door on the back side).

iii. Panels shall be painted by dry electro-static powder coating process.

iv. All accessories mounted on the front panel shall be flush mounting type.

v. Each panel will have mimic diagram painted or embossed on its front.

vi. Each panel will have arrangements for internal lighting and heating.

vii. The wires and wiring accessories, terminations etc. shall be as per relevant

Indian Standards.

The unit control board for each generating unit shall accommodate necessary relays,

measuring instruments, indicators, control unit, control switches, annunciator, temperature

scanner etc. for the operation of the generating units. The generating units shall be controlled

from this control panel during starting, stopping and normal running in manual and auto

modes.

3.17 SYNCHRONIZING PANEL

Synchronizing equipment with check feature shall be provided for synchronization of

the generating units at the 415 V bus bars and shall comprise of a centrally positioned panel.

All the indicating meters with associated switches and fuses should be mounted on the upperhalf of Central panel so that it is easily visible to the operator.



49

Synchronising switch shall be mounted near each generator circuit breaker control

switch on the respective unit control panel. Contacts provided in each switch shall be

connected in the closing circuit of the respective breaker so that the breaker can not be closed

until the switch is turned to the “Synchronising” position. Switches shall be arranged so that

the handle will be locked only in the ‘OFF’ position and check synchronizing relay shall beprovided, so that the breaker could be closed only when voltage, frequency and phases are

properly matched.

Provision for closing the breaker without synchronising check should also be made

with the check synchronising switch in OFF position.

All necessary interlocks, auxiliary potential transformers, auxiliary relays, wiring of

the synchronizing bus inside the control panel, fuses, clamps and other accessories for

satisfactory synchronizing operation shall be provided by the contractor. The synchronizing

scheme is subject to purchaser’s approval.

Computer based auto synchronization shall also be provided in addition to manual

synchronization with an appropriate change over switch on the control panel.

3.18 ANNUNCIATION SYSTEM

A multipoint microprocessor based annunciator with suitable number of ways for

projecting visual signals and audible alarm in case of fault shall be provided on the control

panels suitably. The annunciator shall be back connected flush mounting, dust tight and

tropicalised and shall be complete with audible warning device, and apparatus as required to

complete the annunciator system. It shall be suitable for operation on 24 V.D.C. supply.

The operation of the annunciator system shall be as follows: -

(i) When an external initiating contact is closed, the audible warning shall sound

continuously and the appropriate facia shall be illuminated by flashing light.

(ii) An “acknowledge” push button shall be provided on the annunciator unit

which when pressed shall stop the audible signal and cause the facia to remain

illuminated steadily.

(iii) The annunciator facia illumination shall normally be designed to retain the

indication after the re-opening of the initiating contact. A “reset” push buttom

shall restore the annunciator to the normal condition.(iv) A “test” button shall be provided close to the “acknowledge” and “reset”

buttons to illuminate all the facias on the associated display unit for as long as

the test button is held in pressed condition.

(v) In case there is a second fault on a system when the first is already being

shown by the facia, the annunicator shall show the second fault also even

when the first is existing on facia.

The following facility shall be provided with each of the annunciator points: -

It shall be possible to use “Normally open” type contacts as initiating contacts for the

annunciator. It shall also be possible to use a few “Normally closed” type of initiatingcontacts, if required.



50

It will be the responsibility of the contractor to provide all the alarms and

annunciations required for the safe and efficient operation of the power station.

An A.C. operated relay with A.C. buzzer and A.C. indicating lamp with reset push

button shall be supplied for annunication of D.C. supply failure.Alarm horns, flicker light relays, necessary hardware and any other auxiliary

equipment required to complete the annunciation system shall be provided.

3.19 FACTORY TESTING

3.19.1 Equipment Tests

Each individual equipment shall be routine tested as per IEC/IS at the work’s of

supplier in presence of Owner.

3.19.2 System Tests

The contractor shall organize and execute a complete factory test of the system. The

system shall be erected in his workshop in the engineered configuration and shall be tested

for the following:

i. Operation requirements

ii. Operating characteristics

iii. Response times

iv. Software functions used in PLC based unit controller.

v. Deficiencies

Various process signals shall be simulated for carrying out above system tests. The

Supplier shall submit routine test reports of each equipment and the total system.

3.20 SITE TESTING

The contractor shall carryout tests at site as per relevant IEC/IS standards as follows

in the presence of and to the entire satisfaction of the owner:

i. Calibration checks (on sample basis) on all factory calibrated meters and

transducers.

ii. Acceptance tests on all other devices fitted on the unit control boards and earliertested in factory.

iii. IR tests on panels.

iv. Continuing and IR tests on external cablings.

v. Calibration checks/acceptance tests on all devices and equipment connected to the

unit control boards.

vi. Functional checks on each equipment/object controlled from unit controllers with

control circuits de-energised.

vii. Functional checks on unit controllers with power circuits de-energised.

viii. Verification of all manual control functions from unit control board.

ix. Verification of all control sequences from unit controllers with power and control

circuits energised.x. Watch up each generating unit and perform all start/stop sequences on it.



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3.21 DRAWINGS

(i) The tenderer shall submit three sets of drawings of the equipment offered

along with illustrated and descriptive literature for scrutiny and record.

(ii) Certified copies of type test certificates.(iii) Detailed dimensions drawings along with mounting details.

3.22 SPARE PARTS & TOOLS

The tenderer shall supply spares required for maintenance for a period of five years

and special tools required for site assembly, erection, testing and commissioning,

operation and maintenance.



52

SECTION -IV

TECHNICAL SPECIFICATION FOR

CONTROL PROTECTION, METERING, SUPERVISORY CONTROL AND DATAAQUISITION SYSTEM (SCADA)

(FOR SHP ABOVE 1 MW TO 5 MW CAPACITY)

4.0 SCOPE

The Contractor shall design, fabricate, assemble, test at manufacturers works, supply,

deliver, erect, test at site, Commission and train owner’s operating personnel for the

Control, Protection and Metering Equipment and System for power generation,

transformation and transmission and comprising of following.

A Manual (conventional) Control and Protection System.

(i) Unit control, metering and protection relay panels (For units 1 & 2).

(ii) 33 kV Feeders and bus sectionaliser C.B. control, metering and protective

relay panels.

B Supervisory Control and Data Acquisition System

4.1 APPLICABLE STANDARD

1. ANS/IEEE 1020 – 1987 – IEEE Guide for Control of Small Hydroelectric

Power Plants

2. IS/IEC/ISO Standard Mentioned in Text

4.2 CONTROL AND MONITORING SYSTEM

General Considerations

Considerations involved in providing control and monitoring systems for the power plant

and the switchyard are as follows:

a) Main Single Line Diagram is shown in drawing (to be supplied by Purchaser);

Metering and Relaying as proposed is shown in drawings(to be supplied by

Purchaser).

b) The power house is proposed to be controlled supervisory control from

centralised control room Accordingly provision is to be made for manual and

automatic control for unit starting, unit stopping and running control and data

acquisition at the power house in centralized control room.

c) Control of unit operation is detailed in para 1.2.1.

d) Dependable digital controls for system control with conventional manualcontrol as backup are proposed.



53

e) The turbines, generators, transformer and other equipment proposed for the

unit will be provided with necessary sensors and actuators. Control shall meet

the operational requirement of Butterfly valve which is closed by weight under

emergency.

f) The generators are proposed to be provided with static excitation system.

g) Two number 3.3/33 kV unit transformers of -- MVA capacity each areproposed to step up the generated power to 33 kV.

j) A single 33 kV bus is proposed.

The scheme will be designed in accordance with ANS/IEEE – 1020 and will be

subject to approval by owner.

4.2.1 CONTROL OF UNIT OPERATION

The generation units of power plant are proposed to be controlled by push button

from the main centralized control Board in the power Station with provision of

control from SCADA system in the control room. Suitable interlocks shall beprovided to safe guard the machine against inadvertant faulty operations and to ensure

correct operation of all sequences when starting the machine from the power stations

or from remote station.

Normal Starting

The normal starting and stopping of each unit is proposed effected through local

remote switches to energize a sequence controller installed on the control panel of

each unit.

The master controller switch in the first step of its sequence, shall open-turbine inlet

valve and start unit auxiliaries.

In the second step of the sequence the turbine shall be started and field breaker is

closed.

Synchronization shall be by auto-synchronization as part of SCADA after second

step. Provision of standby manual synchronization in the third step is also required.

Loading of generating unit shall be in the fourth by remote control of the limiter

motor and speed level motor.

Normal stopping of the unit is similarly achieved in steps.

Unit Stopping on Emergency



54

Automatic protective devices shall be provided to detect failures in normal operating

conditions of the various equipments and secure an emergency stop of the unit

whenever necessary and actuate alarms.

It is tentatively proposed that emergency stopping of the units should occur in thefollowing cases:-

a). Electrical protection operation

b). Mechanical protection operation.

c). Turbine speed 115%

d). Turbine over speed 130% (tentative figure)

Emergency closing of turbine inlet valves is proposed in the following case:

a). Turbine speed 140% (tentative figure)

Hydraulic Control

It is proposed to provide a system of water level controls based the for transmission of

storage reservoir laves to the power plant and actuate alarms/shutdown whenever the

levels goes beyond abnormal values and trail-race level by means of sensor installed

in tailrace well for actuating runner blade angle.

4.3 CONTROL AND MONITORING OF PLANT EQUIPMENT

4.3.1 General

The control system shall receive input signals from main equipment such as the

turbine or the generator, and from various other equipment, such as the governor,

exciter, etc. Status inputs shall be obtained from control switches, level and functionswitches indicative of pressure, position etc, throughout the plant. The proper

combination of these inputs to the control system logic will provide outputs to the

governor, the exciter, and other equipment to start or shutdown the unit. Any

abnormalities in the inputs must prevent the unit’s startup, or if already on-line,

provide an alarm or initiate its shutdown, depending upon the magnitude of

abnormality.

The unit control boards should be designed to perform the following functions:

(i) Information receipt and monitoring

(ii) Start/stop sequencing control (iii) Annunciation of alarm conditions



55

(iv) Temperature information monitoring

(v) Metering and instrumentation signals display

(vi) Event recording, when required

(vii) Synchronizing and connecting the unit to the system

The unit control board is the central control means and communicates with the mainand associated equipment through hard wire or multiplexing.

4.3.1.1 33 kV line Control

Manual remote control of the 33 kV Vaccum/ SF6 breaker is proposed in the powerhouse

in the centralized control room.

4.3.1.2 Station Service System

The unit auxiliaries are proposed to be provided automatic control to suit the unit control

as proposed for manual/supervisory control room centralized control room.

4.3.1.3 Annunciation

Annunciation system is proposed to be designed for control of the unit from the

powerhouse in centralized control. The normal annunciators consisting of indicating

lamp and relay assembly is proposed to be provided on the unit control boards in the

powerhouse.

Data logging – Data will be stored in hard disc and printed every half an hour for which

printer will be provide at centralized control room.

4.3.1.4 Auxiliaries Control

Centralized controls of the power distribution and control boards is proposed for attended

automatic operation. Automatic switching of selected standby and emergency auxiliaries

on failure of running auxiliaries is proposed. Automatic change over of entire unit

auxiliaries to alternate source of supply is also proposed.

4.3.1.5 Switchgear and Motors

Air break switchgear is proposed to reduce fire hazard. The opening/closing time of

switchgear may not exceed 8 cycles so that stalling of motors on change over does not

take place. All motors will be direct on line starting and are therefore high starting

torque.



56

4.3.2 Control and Status Data

Control and status data to be transmitted from various equipment to Unit Control

Board and from Unit Control Board to the equipment etc is detailed below. This is

tentative and may be increased or decreased as required with owner’s approval.

Information and control signals will be needed between the control board and each of the

following:

1 Turbine Table – 1.1 to 1.3

2 Turbine speed governor Table – 2.1 to 2.3

3 Generator Table – 3.1 to 3.44 Generator excitation system Table – 4.1 to 4.3

5 Unit transformer Table – 5.1 to 5.2

6 Circuit breaker and switches Table – 6.1 to 6.2

7 Intake valve and draft tube gate Table - 6.3

8 U/S and D/S water level

Additionally, control signal shall also be from Auxiliary equipment, Fire Protection,

Auxiliary AC Power Supply, DC Power supply, Service Water, Service Air shall be

provided as per IEEE – 1020.

These equipment blocks represent auxiliary service equipment needed for the proper

operation of the generating plant. Abnormal conditions of this equipment will be alarmed.

Table- 1.1 - Control and Status Data Transmitted form Turbine toUnit Control Switchboard

SIGNAL DESCRIPTION TYPE NOTES

38TG Turbine guide bearing

temperature

T,A,P,I Temperature detectors, Provision

for mounting two sensors in

bearing shell.

38QTG Turbine guide bearing oil

temperature

T,A,P,I Temperature detector in bearing oil

reservoir.

71QTGH Turbine guide bearing oil

level high

A Sensor in bearing oil reservoir,

with direct reading visual indicator

71QTGL Turbine guide bearing oil

level low





57

33SP Wicked gate shear pin

failure

A Shear pin failure while closing

wicket gates due to obstruction

80WB Bearing cooling water low

flow

A Pump failure, obstructed piping or

pipe rupture.

71WTH Turbine pit water high level A, C Senses excessive water level in

turbine pit due to plugged drains or

major seal failure. One contact

operates submersible pump.

SCWP Water pressure in Intake P, I Direct reading on transducer

operated gauge.

Unit startup interlock, shutdown if

loss of pressure in running unit

DTWP Draft tube water pressure-

vaccum

I Direct reading on transducer

operated gauge

48TG Turbine greasing system

failure ( if greasing system

provided )

A Alarm if lubrication cycle not

completed

74TG Turbine greasing system low

voltage( if greasing system

provided )

A Detects failure of power supply to

solenoid valve used to control

greasing cycle.

Wicket Gate ServomotorPosition

C Feedback to the governor controlsystem.

Runner Blade Servomotor

Position

C Feedback to the governor control

system.

TYPE C = Control

P = Protection Trip

A = Annunciation/Event Recording

T = Temperature Monitoring

I = Indication (analog, digital, status lamps)



58

Table- 1.2 - Control and Status Data Transmitted from UnitControl Switchboard to Turbine


1GS Turbine grease system

Start/Stop (if greasing

system provided)

C Enables grease systemwhen unit is running.

1TL Turbine lube oi lsystem start /stop

C Enable turbinelubricat ion pr ior to unit

run.

Type

C = Control

P = Protection Trip

A = Annunciat ion/Event RecordingT = Temperature Monitoring




59

Table‐1.3 ‐ Operating Power, Air and Water from Service Equipment to Turbine

DESCRIPTION TYPE NOTES

Power supply for control and protection

devices

DC

Power supply for turbine pit water pump AC

Air supply for shaft maintenance seal. A

Water supply for bearing oil coolers and

turbines seals

W

Power supply for Lubricating oil system

for bearing

AC May be alternately fed from

DC.

Type

AC = AC Power

DC = DC Power

A = Air

W = Water

Table 2.1 – Control and Status Data Transmitted from Governor to Unit Control

Switchboard

Signal Description Type Notes

N Speed indication I Methods of developing the speed signal include

the following :

- Hall-effect, eddy current, magnetic

sensors operated in conjunction with

toothed wheels or other devices directly

connected to the generator shaft (speed

signal generator – SSG)

- Voltage transformers connected to the

generator output leads must be capable of

operating at very low residual voltages in

absence of field excitation



60

12-X Over-speed C, P Over-Speed Switch should be actuated

mechanically by means of a centrifugal device

mounted on the turbine shaft.

12-X1

13-X

14-X

Over-speed,

Synchronous

speed and underspeed switches

C, P Electrically actuated speed relays by comparing

the speed signal to a reference signal

65SF Speed signal

failure

A,C,P Loss of speed signal may initiate control action

i.e. shutdown of the unit and annunciation.

39C Creep detector

operation

A,C Control action upon detection of shaft movement

after shutdown may include any or all of the

following :

- Start thrust/guide bearing HP oil pump

- Release brakes- Drop intake gates

- Alarm

- Start turbine guide bearing oil pump

65Ss Start/stop solenoid

auxiliary contacts

or gate limiter

limit switches

C,I Provides information of starting /stopping

process.

65SNL Speed-no-load

solenoid aux.contacts or gate

position

C,I Provides confirmation of 65SNL operation. Used

to seal in remote controls and provide remoteindication.

WG Wicket gate

position indication

C, I Typically derived from potentiometer or LVDT

coupled to restoring connection from wicket gate

servomotor.

33WG Wicket gate

position switches

C,P,I Typical uses of gate position switches for control

and indication:

- Generator brake application (that is, apply

brakes at low speed if gates at 0%)- Turbine gate lock (apply at 0% gate

position)

- Trip generator breaker as gates pass

through speed-no-load position (auto-stop,

protective shutdowns without overspeed)

- Incomplete stop detection

- Unit running detection

- Initiate time delay for stopping auxiliaries

- Reenergize starting relays to provide

restart after momentary loss of power



61

71 QP Governor Oil

Pressure Unit – oil

level switches in

Pressure Vessel

A, P Alarms for high, low and extreme low levels.

Shutdown for extreme low level, air admission

for high level.

63Q Governor OilPressure Unit -

pressure switches

on Pressure Vessel

A, P Pump control, alarms for low and extreme lowpressures, shutdown for extreme low pressure.

71 QS Governor Oil

Pressure Unit –

level switches for

oil level in sump

tank

A Alarms for high and low oil levels.

26QS Governor Oil

Pressure Unit –

sump tank oil

temperature high

A Indicative of excessive governor action.

6Q Governor Oil

Pressure Unit –

standby pump

operation

A Indicative of excessive governor action or pump

failure

27PS Governor powersupply failure A,C,P Indicates failure of input AC or DC power orfailure of regulated DC power supplies. May

result in unit shutdown depending upon level of

power supply redundancy.

63AB Generator air

brakes applied

C,I Indication and auto-start interlock.

63ABS Generator air

brake supply

pressure low

A

33WGL Wicket gate

automatic lock

applied/released

C, I Indicates status of the gate lock (applied on

shutdown when gates at 0%)

65WGLF Wicket gate

automatic lock

failure

A Indicates that the gate lock has not been fully

applied on shutdown

65M/LS Manual control

indication

I Provides remote indication that the governor is in

manual control at the governor cubicle



62

C = Control

P = Protection trip




Table 2.2 – Control and Status Data Transmitted from Unit Control Switchboard to Governor


39 Creep detector

enable

C Enables rotor creep detector after a fixed time

following application of brakes on shutdown

15FR,

15FL

Speed reference

raise /lower

commands

C Typically relay or switch contact closures. If power

reference also provided, speed raise/lower operable

only off-line. Some installations may utilize input

reference analog or digital signal rather than raise /

lower commands

65PR,

65PL

Power

reference raise

/lower

commands

C Typically relay contact closures when unit on –line.

Some installations may utilize input reference

analog or digital signal rather than raise/ lower

commands

65GLR, Gate limit

raise/lower

commands

C Typically relay contact closures, route to reversing

drive motor. Primary function of the gate limit (GL)

is to limit the maximum opening of the wicket gatesunder operator control to prevent overloading the

unit at the prevailing head. Other control and

protection applications include:

- Pre- positioning GL to 0%prior to starting to

permit controlled opening of the gates upon

energization of the start / stop solenoid

65SS

- Raising GL to turbine breakaway gate

position after energization of 65SS

- Rapid unloading of the machine during

certain stop and protection shutdown

sequences



63

3SS On-off

command to

start/stop

solenoid 65SS

or gate limiter

motor

C,P The start/stop solenoid 65SS typically operates as

follows :

- Energized to allow wicket gates to open and

close under control of the electric governor,

gate limit or manual gate control, that is,

“energized to start and run”- De-energized to initiate complete closure of

the wicket gates at maximum rate and block

subsequent opening of the gates, i.e. “de-

energized to stop”

Typical functions that will block start and/or initiate

stop are

- Unit protection operation (includes all

electrical and mechanical fault detectors that

initiate shutdown of the unit)

- Operator-initiated stop- Generator thrust bearing high pressure oil

pump failed to achieve full pressure

- Turbine shaft maintenance seal on or low

gland water flow

- Generator brake shoes not cleared or brake

air pressure not off, or both

- Intake gate not fully open

- Generator and turbine bearing cooling water

not available

- Wicket gate lock not released

3SNL On/off

command to

partial

shutdown

(speed-no-load)

solenoid

C,P The partial shutdown solenoid 65SNL (if used) is

typically de-energized to limit the opening of the

wicket gates, or return them, to a position slightly

above the speed-no-load position and is controlled

as follows :

- Energized when unit circuit breaker closes to

allow generator to be loaded

- De-energized whenever unit circuit breaker

trips to restore unit to near rated speed;

provides backup to the electric governor

- De-energized to unload the unit for certain

protection operations (that is over speed to

112% during opening of unit circuit breaker)

V, I Generator

voltage and

current

C Inputs to power transducer (for governors utilizing

power feedback rather than gate feedback)

52 Unit on-line C Generator circuit breaker auxiliary contact. Used to

switch between on-line and off-line gains incompensation circuits (PID) and to switch between



64

speed and power references

3AB Generator air

brakes on/off

command

C Air brakes automatically applied on shutdown if

wicket gates close and speed below a predetermined

level

71NH Level

difference

between

headwater and

tailwater

C Used for optimum turbine blade positioning and

optimum gate position/ power generation.

Type

C = Control

P = Protection Trip



I = Indication analog, digital, status lamps)

Table 2.3 – Operating Power, Air and Water from Service Equipment to Governor

Description TypeNotes

Power supply for DC control DC One or more separate supplies depending on

power distribution arrangement

Power supply for Oil Pressure

Unit pumps

AC One or more separate supplies depending on

number of pumps and required redundancy.

Alternate supply for governor

power supplies

AC

Air supply for generator air

brakes

A

Air supply for Oil Pressure Unit A

Cooling water for Oil Pressure

Unit oil sump

W (Optional)

Type

AC = AC Power

DC = DC Power

A = AirW = Water



65

Table 3 .1 – Control and status data Transmitted f rom Generator to

unit control

Switchboard


26GS

38THT

38GT

38QB

26GF

71QBH

71QBL

Stator winding

temperature

Thrust bearing

temperature

Guide bearing

temperature.

Bearing oil

temperature

Generator field

temperature.

Bearing oil level high

Bearing oil level low

T, A, P

T, A, P

T, A, P

T, A, P

T, A, P

A

A

Temperature detectors (typically 12)

embedded in stator winding accordance

with ANSI C50. 10-1977 (1). Two hottest

RTDs connected to thermal overload relay

49G.

Temperature detectors embedded in wells inthe shoes or segments with provision for

interchanging sensors between segments.

Temperature detectors. Provision for

mounting sensors in all segments.

Temperature detectors in bearing oil

reservoir.

Temperature monitoring system for

continuously monitoring field temperature.

One sensor for oil reservoir, equipped with

direct reading visual indicator

One sensor for each separate oil reservoir,

equipped with direct reading visual

indicator.

33AB

CT-G

Air brake positionindication

Neutral end and

terminal end current

transformers

C, I

P, I

Start interlock indicating all brake shoeshave cleared runner plate.

Furnished in quantities and ratings

compatible with the metering and

primary/standby protection requirements.

TYPE

C = Control

P = Protection tripA = Annunciation/Event Recording



66



Table 3.2 – Control and status data Transmitted from Generatorto unit control

Switchboard

SIGNALDESCRIPTION TYPE NOTES

2THS

1GL

Thrust bearing high

pressure oil pump start/

stop command.

Generator lube oil system

start/stop command.

C

C

Start pump prior to starting unit.

Confirmation of pump starting via63QTH

(Table 3A-1)

Enables generator lubrication prior to unit

run.

When forced air cooling is used for the

generator.

Turned off when unit is on-line.

TYPE

C = Control

P = Protection trip


T = Temperature MonitoringI = Indication (analog, digital, status lamps)

Table 3 .3 – Operating Power, Air and Water from Service Equipment

to Generator


Air supply for brakes and rotor jacking

system

Water supply for fire extinguishing

system

Power supply for generator housing

space heaters.

Power supply for generator lube oil

system.

A

W

AC

AC

Control valve may be located in governor

cubicle/ generator brake panel.

May also be atomized.

Thermostatically controlled, for reducing

condensation on windings when generator is

shut down.

May be fed alternatively from DC source.

TYPEC = Control



67

P = Protection trip




Table 3.4 – Control and Status Data Transmitted from Generator Terminal

Equipment to Unit Control Switchboard

SignalDescription Type Notes

CT Current signal for relaying and

metering

VT Voltage signal for relaying and

metering

A Current indication I

F Frequency indication I

V Voltage indication I

W/VAR Metering I,A Analog signals for

indication and/or recording.

AVR Voltage signal for automatic voltage

regulator (AVR)

C Analog signal from a VT.

N Governor speed sensing C

XDCR Power transducer C Unit power input to electric

governor.

TYPE

C = Control

P = Protection Trip


T = Temperature MonitoringI = Indication, analog, digital, status

lamps)



68


51ET Exciter transformer o/c

protection

P

49 GF Field overload 1 Set to coordinate with field winding thermal

characteristic

I f Field voltage indication 1 Transuded from DCCT ( satiable reactor )

V f Field voltage indication 1

64 F Field ground detection P or

A

27 FF Failure of preferred field

flashing source

A Provision of this alarm assumes 2 sources

provided AC and DC. AC should be

preferred source to minimize chance of back

feeding field voltage onto battery if blocking

diode fails. Automatic transfer to alternate

source on failure of preferred source

41/a,41/

b

Field breaker position C,I

31/1,31/

b

Field flashing contactor position I

48E Exciter start sequence

incomplete

P,A Set to operate after normal time required for

field flash source to build terminal voltage to

level sufficient for exciter gating to

commence.

63F-1 Cooling fan failure A/P Failure of redundant fan (s).

27PS DC power supply failure P or

A

Trip or alarm depending on level of power

supply redundancy.

26ET-I Exciter transformer over

temperature –Stage I

A Indicating unit with dial contacts typical.

26ET-2 Exciter transformer temperature

–Stage 2

P

Table 4.1 – Control and Status Data Transmitted from excitation system

to unit control switchboard



69

58-1 Rectier transformer temperature A Thyristor fuse, conduction, or gating failure.

-

58-2 Rectifer failure –Stage 2 P

49 HE Heat exchanger failure A Various heat exchanger arrangements arepossible Once-through, closed system, etc

26RTD Exciter transformer temperature

indication

I Temperature detectors . Quantity variable

depending on number of secondary winding

and whether transformer is 3 phase or 3 x 1

phase.

70V Manual voltage adjuster with I Signal generated by potentiometer coupled to

70V motor drive.

70V/LSI,

2

70V End-of travel indication I Signal generated by limit switches coupled to

70V motor drive

90V Auto voltage adujster with

position

I Same as 70V.

90V/LSI,

2

90 V End-of –travel indication I Same as 70V/LSI,2.

70V/LS3 70V preset position C Interlock in start sequence

90V/LS3 90V preset position C Interlock in start sequence.

89LS Station service A.C test supply

switch position

I Optional

MAN Indication mismatch between

auto & manual

I To ensure bumpless transfer from AUTO to

Manual

AUTO Voltage regulator output and

manual

I MAN and MAN to AUTO

Balance Voltage setpoint


TYPE

C = Control

P = Protect ion Trip

A = Annunciation /Event recordingT= temperature Monitoring



70

I = indication (analog, digital, status lamps)

Table 4.2 – Control and Status Data transmitted from unit control Switchboard

to excitation


41

protective

trips

Field tripping from generator P

41 control Field breaker tripping from

manual control and unit

shutdown sequence logic

C

41 close Field breaker closing from

manual control and unit start

sequence logic

C

IE Exciter de-excite C Close contact to initiate field

flashing at 95% speed during

auto start or under manual

control

IE Exciter de-excite C Open contact to initiate phase

back below 95% speed, unit

separated form system

83VT Voltage transformer potential C Transfer exciter from autovoltage control to manual

control

43AM Close contact transfer exciter

to manual voltage regulator

control

C

43VA Close contact to transfer

exciter to auto voltage

regulator control

C

70V Rum.Back logic

Run 70V to preset positionpreparation for unit starting C

90V Rum.

Back logic

Run 90V to preset position

preparation for unit starting

C

70 V raise Raise manual voltage

adjuster

C

70 V lower Lower manual voltage

adjuster

C

90 V raise Raise auto voltage adjuster C



71

90 V lower Lower auto voltage adjuster C

52G/a Generator CB Auxiliary

switch

C De- excite control, disable

power system stabilizer of-line.

Wicket

gateposition

Analog signal representing

wicket

C Used to develop accelerating

power input to PSS if required

TYPE

C = Control

P = Protection Trip

A = Annunciation /Event recording

T = temperature Monitoring


Table 4.3– Operating Power, Air and Water from Service Equipment to

Excitation system


Battery-fed field flashing DC

Station service field flashing

source

AC AC preferred source. Auto transfer to dc if ac

not available

TYPE

C = Control

P = Protection Trip

A = Annunciation /Event recording



Table 5 .1 – Control and Status Data Transmitted from Step up

Transformer to Unit Control Switchboard

Signal Description TypeNotes


metering

A, P, I



72

71G Gas accumulation detection A Event recording (optional).

63G Gas pressure device A, P Event recording

63Q Main tank sudden pressure relief

device

A, P Hand reset contact (local). Event

recording

63T Main tank over pressure switch A, P Trip generator breaker

49-1W

49-2W

Transformer winding temperature

thermal device in each separate

winding

A, T, P Temperature detectors embedded

in each separate winding for first

stage temperature control. RTD

are in each winding because of

the possibility of unbalanced

loading.

26Q Top oil temperature indicator A, T Dial type oil temperature

indicator at the transformer. First

stage annunciation, trippingoptional. Second stage tripping

71QC Conservator tank oil level indicator A Dial type indicator with

maximum and minimum

indicating levels. Tripping

optional.

Table 5 .2 – Operating Power, Air and Water f rom Service

Equipment to transformer Description Type

Notes

Power supply for DC control

circuits

DC For uninterruptible systems.

Power supply for fans, pumps,

ac control circuits

AC For FA, FOA transformers. If an FOW

transformer is used, additional

information and control signals may be

needed, such as monitoring of the

pressure difference between the oil and

water systems.

Water supply for fire

extinguishing system

W

Type

AC =AC Power

DC =DC PowerA =Air

Table 6 .1 – Signals Transmitted from Plant Equipment t o Generator

Breaker


4 Unit control C Normal shutdown



73

1XJ Breaker control switch, trip/close C

12G Generator overspeed P

25 Synchronizing equipment C

33 Wicket gate position switch C Permissive switch38GB Generator bearing temperature P

38TB Turbine bearing temperature P

43XJ Breaker test switch C

49T Step-up transformer over temperature P

63T Step-up transformer sudden pressure P

71K Kaplan low oil P

80TBQ Turbine bearing oil P38G Generator winding temperature P

43S Unit synchronizing selector switch C Permissive switch

Table 6 .2 – Signals Transmitted from generator Breaker to Unit

Control Switchboard


52a, b Breaker open-close C, I

27CB Generator breaker loss of dc control

power

A

61 Generator breaker pole failure P, A Trip is isolate breaker.

63a Breaker air pressure switch C Permissive switch.

63A Generator breaker low air pressure P, A

Type

C =Control

P =Protection TripA =Annunciation/Event Recording

T =Temperature Monitoring

I =Indication (analog, digital, status lamps)



74

Table 6.3 – Inlet Valve and Draft Gate Controls for automatic operation of the Inlet Valve shall as follows:

1 Unit Control Board • Indicating lights for fully open/fully

• Position indication showing actual positionof the gate

2 Local • Open/Close control switch

3 Annunciation • Failure of valve to open or close in response

to an automatic signal

• Hydraulic system trouble



75

4.4 MANUAL CONTROL, METERING AND PROTECTION SYSTEM

4.4.1 Scope of Supply and Design Criteria

Design, manufacture, testing, commissioning of manual control, metering and protection

system which includes Electrical protection by conventional relay; manual control andmetering of the Power House.

4.4.2 Standards

All materials and equipments shall comply in every respect with the requirements of the

latest edition of the relevant Indian, British equivalent N.E. M.A. I.E.C. Standards or any

other recognized International standards, except in so far as modified by this

specification. Where standards offered are other than the Indian or British standards,copies of the relevant standard specification in English language must be attached.

4.4.3 Design Criteria

The control will have provision for start, stop,, manual synchronizing and emergency

stop. Sequencing will be as per control of unit operation as given below: -



various relays are explained in following drawings(to be enclosed by Purchaser).

i. Main Single Line Diagram

ii. Interconnection with Grid

iii. Protection & Metering Single Line Diagram

iv. Auxiliary Power Single Diagram

v. Unit Metering and Relaying Single Line Diagram

Common tripping relays for similar functions have been provided with lockout

facilities. All these relays shall have potential free contacts for trip and alarm purposesand externally hand reset type of flag indicators. They should preferable be housed in

drawout type of cases with tropical finish.

All the protective equipment will be housed in the Power Plant main control room.

The details of C.T.’s for all the unit protection and metering are given in Drawings

No-----. The secondary current of C.T.’s located in switchyard is proposed as 1 amp.

because of long leads so as to ensure efficient and accurate operation of their

protective scheme.

3.3 kV C.T.s and P.T. may be mounted on 3.3 kV switchgear panels’ alongwith

relays.



76

4.4.5 Protective Relays

A brief description of protective relay proposed is given below:

4.4.5.1 Generator Protection

i) Generator Differential Protection (87G)

The generator primary protection is proposed by high impedance type of

circulating current relays having proper setting range. The relays will be of

high speed type and shall be immune to A.C. transients. Necessary provision

shall be made in the relay to ensure that the relays do not operate for faults

external to the protected zone. The relays shall not maloperate due to

harmonics in spill current produced by through faults or due to saturation on

one set of current transformers during an external fault. Provision shall also bemade for alarm /indication in case of current transformt fault.

The relay operation actuates lockout relay for complete shutdown of the unit

Drawing No. -----.

ii) Generator ground fault protection (64G)

The generator neutral will be earthed through the primary winding of a

distribution transformer of proper capacity and ratio. The secondary will be

loaded by a suitable resistor rated for 60 seconds. A suitable voltage relay with

continuous coil rating with proper setting is proposed to be provided. The

relay shall be insensitive to voltage at third harmonic frequencies.

The relay operation actuates lockout relay for complete shutdown of the unit.

iii) Neutral Grounding Transformer and Loading Resistor

Neutral Grounding Transformer

a. Type Dry type, Natural air cooled,single phase.

b. Connection Between generator neutral

and ground

Loading Resistor

a. Construction Non-ageing, corrosion

resistant, punched stainless

steel grid elements provided

with necessary installations,

and temperature rise not

exceeding 300 deg. C.

b. Housing Enclosure with IP:22 degreeof protection. However,



77

transformer and resistor can

be housed in same container

with metallic partition.

iv) Generator over-voltage protection (59)

A set of single phase relays is proposed with suitable time delay setting so that

operation of relay under transient conditions is avoided. The relay setting

range is proposed from 110% to 150%. The relays shall be immune to

frequency variation. Provision of instantaneous tripping element at some

suitable setting is also proposed.

The relay is set to operate lockout relay for partial shutdown to speed no load

position.

v) Negative phase sequence current protection (46)

Protection will detect unbalance in the outgoing lines which will be detected

and operate the relay. The current transformer for this protection is proposed

to be located on the generator neutral side.

The relay is set to operate the lockout relay for partial shutdown to speed no

load position.

vi) Voltage restraint over current protection (51V)

This backup protection for the generator operates for over current which are

accompanied by dip in voltage so that false tripping due to through faults are

avoided. The relay is set to trip lockout relay for partial shutdown to speed no

load position.

vii) Reverse power relay (32)

This relay is proposed because of grid connection. The relay is proposed to be

set to trip lockout relay to speed no load position.

viii) Check Synchronising relay (25)

Check synchronising relay is provided to ensure the closing of the circuit

breakers on synchronising at a phase angle not greater than about 7 degrees so

as to prevent damage to circuit breaker especially in case of auto

synchronising.

ix) Potential transformer fuse failure protection (60)

Suitable voltage balance relays are proposed to monitor the fuse failure of 3

sets of potential transformers and to block the relays (50/51 V or 40) or other

devices that may operate incorrectly on the voltage due to fuse failure of potential transformers. The relay is set to give an alarm only.



78

x) Mechanical Protections

Following mechanical protections are proposed for the generator:

e. Resistance temperature detectors in stator core (12 no.) and in thebearings for indication, alarm and recording. RTD’s are to be provided

by Generator Suppliers.

f. Turbine and generator bearing, metal and oil temperatures –

alarm/shutdown.

g. Governor oil pressure low to block starting and low-low for emergency

tripping.

h. Over speed for normal and emergency shutdown depending upon its

extent.

i. Contractor will co-ordinate with Generator and Turbine supplier for

mechanical protection.

4.4.5.2 Exciter Protection

i) Generator field failure protection (40)

The tripping of the relay is set to open the excitation breaker main generator

C.B., 33 kV trans. C.B. & UAT breaker and shut down the turbine on

immediate shut down mode.

ii) Generator rotor earth-fault protection (64F)

The protection shall consist of two stages. The first stage with a lower range

shall be arranged to give alarm and annunciation. The second stage with a

higher range shall carry out tripping of the gen. C.B., UAT breaker, field

breaker and shut down the turbine on immediate shut down mode.

iii) Over current relay (51 EX)

This over current instantaneous relay in the excitation circuit before the

excitation transformer will cater to rectifier transformer faults and other

excitation system faults. This relay is set to trip excitation circuit breaker and

bring the unit to rated speed at no load.

iv) Over excitation relay (OER) in the DC circuit and excitation relay (31) in the

field flashing circuit are other relays proposed in the excitation system.


i)

Over Current Protection (51)



79

Suitable relays are proposed to be provided for unit auxiliary transformers

over load protections. The relay will operate from the three current

transformers on the Low Voltage side of the transformer and will be arranged

to trip the Low Voltage breaker.

An instantaneous time over current relay is proposed from the CT’s on the 3.3

kV side of the auxiliary transformer. This relay at a higher setting will cater to

transformer faults and the tripping of the relay is set to bring the unit to rated

speed at no load.

ii) Phase sequence relay (47)

This relay on the station service system trips the LV circuit breaker so as to

prevent operation of the three phase motors in the reverse direction

. iii) Under voltage relay (27)

These relays have been provided to trip the LV circuit breaker

4.4.5.4 Step up 3.3/33 kV Transformer Protection

i) Generator Transformer Differential Protection (87 GT)

A sensitive percentage biased differential relay is proposed to be provided foreach step up transformer protection with proper operating and bias setting. It

shall have harmonic restraint feature to prevent its mal-operation due to

magnetising in-rush surges encountered in normal power system operation.

Provision shall also be made for alarm/indication in case of current

transformer secondary circuits faults.

The C.T.’s on 3.3 kV side are proposed be located in the Generator neutral

side and on 33 kV side in the switchyard. The auxiliary/interposing current

transformers as required for the protection shall also be provided.

The relay is set to operate lockout relay for shutdown.

ii) Standby earth fault protection (64T)

For this protection Inverse Definite Minimum Time Lag type relay having

suitable setting range and operating time is proposed. This relay is proposed to

trip the unit circuit breaker and bring the unit to speed no load. The relay will

be co-ordinated with line earth fault protection.

iii) Bucholz gas pressure relay for first stage alarm and second stage trip.

iv) Transformer oil level and temperature for alarm & trip

v) Winding temperature for alarm & trip



80

4.4.5.4 Bus Bar Protection

Bus Zone Differential Protection (87 B1, and 87 B2)

A high speed, high impedance type bus-bar differential protections proposed to be

provided for each 33 kV bus zone. The scheme shall have separate and independentcheck and supervision features incorporated in it.

Necessary separate C.T. cores shall be provided at the incoming and outgoing circuits

for check features. The main zonal relay and check relay scheme will have their

contacts connected in series in the trip circuit.

The protection will be capable of detecting all type of faults on the bus-bar. The

sensitivity of protection shall be such that it does not operate for faults on the C.T.

secondary wiring of the most heavily loaded circuit. C.T.’s on one side of the bus

coupler/section breaker are proposed and inter-locked overcurrent relay will be

provided.

The supervision relay will be capable of detecting open: Cross or broken C.T.

secondary and pilots by employing sensitive alarm relay, which shall be connected

across the bus wires of each protected zone. It shall be capable of taking the

protection of the effected zone out of service by shorting the appropriate bus-wires.

`No volt’ relays to indicate failure of D.C. alarm and trip supply to the bus-bar

protection scheme is also proposed to be provided.

High speed tripping relays shall be provided to trip the connected circuit breakers

connected to the faulty bus bar.

4.4.5.5 33 kV Line Protection

Protective relay design for the 33 kV line is important because of high fault power

from 33 kV grid sub-stations. Main features of fast acting protection system is

tentatively proposed as follows:

Directional overcurrent and ground fault (51 D)

4.4.5.6 Over under voltage relay/Over under frequency relay

This relay shall be provided on the line and the bus to indicate grid failure conditions. The protection requirement with respect to characteristics operating principle, tripping

schedule and type of relays shall be discussed during detailed engineering stage, and

Bidder shall provide the same to the satisfaction and approval of the Owner.

4.4.6 Metering

Meters as shown in Schematic drawing(to be enclosed by Purchaser shall be provided

on unit control boards. These are summarised below:

4.4.6.1 Generator (Unit Control Board)



81

i. 3 ammeters (each phase)

ii. Power factor and kW meter

iii. kVAR

iv. Voltmeter with voltmeter switch

v. kWH meter

vi. Frequency Meter

4.4.6.2 Auxiliary Transformer

i. kWh meter

ii. Ammeters (3 No.)

4.4.6.2 33 kV Feeder Panel

i. Voltmeter with voltmeter switch

ii. Ammeters (each phase).

iii. Recording kVARiv. k.W.

v. Power Factor metervi. kWh import / export meter.

4.4.7 Annunciation

Conventional 16 window annunciator for each generator turbine faults; 12 window each for feeder faults and Bus Coupler is proposed for important faults. Schedule for these windows may be proposed for approval by purchaser. All other annunciation will be on SCADA system.

4.4.8 Recorder

All recording will be done on SCADA disk.

4.4.9 CTs/PTs and General Surge Protection Equipment

4.4.9.1 All current and voltage transformers required for protection system of the unit are

detailed in generator specifications shall have adequate VA burdens, knee point

voltage, instrument safety factor and characteristics suitable for the application, and

shall be subject to approval of the Owner. 33 kV CTs are detailed in separatesection.9.1.1.

CTs/PTs used for different applications shall have following accuracy class:

a) Differential protection CTs Class PS

b) Protection CTs other than differential protection Class 5P10

c) Generator AVR/metering CTS for generator circuit Class 0.5

d) Metering CTs for 33 kV; 3.3 kV and 415 V switchgear Class 0.5

e) CTs for performance testing and low forward power Relay Class 0.2

f) Core balance CTs Class PS

g) Protection PTs Class 3Ph) PTs for generator metering, AVR synchronisation Class 0.5



82

i) PTs for performance testing and low forward power relays Class 0.2

CTs and PTs details proposed will be submitted for approval by purchaser.

4.4.9.2 Generator Line Terminal and Neutral Grounding Cubicles

These shall be provided as per detailed given in generator specifications.

4.4.9.3 33 kV Current Transformers and Potential Transformers

The technical requirement and location of the CTs are given in the unit metering

and relaying drawing (enclosed). The generator suppliers shall supply suitable

current transformers for the protection scheme and these shall be in the neutral

grounding cubicles.

The potential transformers should be suitable for metering and protection scheme

enclosed.

4.4.10 Control and Relay Panels

Floor mounted, sheet steel simplex type control and relay panels with the following

equipment mounted on them shall be as follows. The details of the panel and

equipment will be supplied for approval by purchaser.

1) Generator transformer control and relay panel - -- Sets.

2) 33 kV feeder control and relay panel - -- Sets.

3) Synchronising panel - 1 no.

4.4.11 Test Blocks

Test blocks shall be provided on switchboards where test facilities are required but are

not provided by use of drawout type meters or relays. The test blocks shall be of the

back connected semi-flush mounted switchboard type with removable covers. All test

blocks shall be provided with suitable circuit identification. The cases shall be dust

tight. Test blocks shall be rated not less than 250V at 10 amps and shall be capable of

withstanding a di-electric test of 1500 V, 50c/s for one minute. All test blocks shall be

arranged to isolate completely the instruments or relays from the instrument

transformers and other external circuits so that no other device will be affected andprovide means for testing either from an external source of energy or from the

instrument transformers by means of multiple test plugs. The test blocks and plugs

shall be arranged so that the C.T. secondary circuits cannot be open circuited in any

position, while the test plugs are being inserted removed.

4.4.12 Factory Tests for Unit Control Switchboards

1. Review front and rear elevations versus the final approved drawings. Check each

item of equipment for proper location and verify the instrument/catalog number iscorrect per the specification.



83

2. Review the interior of the UCS in the same manner as the elevations. In addition,

verify the lighting is adequate and grounding connections are provided.

3. Check anchor channels and cable entrances. Confirm they are in accordance with

the drawings.

4. Review test certificate or witness the insulation resistance test of all wiring,

current transformers, and potential transformers.5. Check approximately 5 to 10 percent of the internal cabling. Verify that the

following items conform to the drawings :

• Cable numbers;

• Terminal block designations;

• Terminal designations on individual components such as control switches

and lockout relay;

• Raceway layouts; and

• Equipment identification nameplates.

6. Activate all protective relays. Confirm that the appropriate lockout relay is

energized and the correct annunciation and/or printout occur.

7. Confirm that settings of all protective relays are in accordance with approved

documents.

8. Check all annunciation points.

9. Check factory calibration of all devices possible, including electronic speed

relays, current and potential transformers, and vibration monitors.

10. PLC checks:

• Check the I/O racks for type and number of analog and digital I/O cards;

• Check for future expansion capabilities on the I/O racks;

• Check for surge protection provided on the I/O rack and I/O cards;• Identify grounding connections for the PLC and the I/O rack; determine

whether chassis and logic grounds are the same or separate (this will affect

the type and quantity of external surge protection required);

• Review the PLC ladder diagram viewed on the video display terminal

versus the final approved PLC software coding documentation; and

• Verify that modem connections are provided and functional.

11. Perform the function checks listed below with the final approved schematics, PLC

software coding, and control block logic diagrams in front of you. All premissives

and interlocks should be provided by using the “dummy” toggle switchboard to

provide these inputs.

• Manual start/stop sequence (does not apply to redundant PLC control

schemes);

• Auto start/stop sequence;

• Manual emergency stop sequence;

• Automatic emergency stop sequence (usually performed by activating one

of the lockout relays while in the “normal running” mode );

• Change position of all control switches as follows (typically done while in

the normal running mode);

- Local control to remote control- Remote control to local control



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- Manual control to automatic control

- Headwater level control “OFF” to “ON”

- Headwater level control “ON” to “OFF”

- Excitation manual control to excitation automatic control

- Excitation automatic control to excitation manual control; and

• Verify the performance of the automatic synchronizing circuit and themanual sync-check relay (if provided).

4.4.13 Field Tests for Unit Control Switchboards

1. Verify tags on all factory-calibrated instrumentation devices.

2. Check all external interconnection wiring against the approved power

house/equipment drawings, verifying the following items :

• Cable numbers and type;

• Terminal block designations; and

• Raceway layouts

3. Perform point-to-point continuity and megger tests on all external cabling.

4. Calibrate all remaining instrumentation devices.

5. “Bench test” all protective relays to ensure proper settings.

6. Perform functional checks tests on all unit and station auxiliary equipment

controlled from the UCS to verify proper operation.

7. Perform functional checks on unit start/stop sequences, duplicating the factory

sequences. These check should be performed first with the associated power

circuits de-energized, and then with both power and control circuits energized.

8. Methodically document steps 1 through 7 to ensure that no cables, instrumentationdevices, protective relays, or control systems have been overlooked.

9. Water-up the unit and perform all start/stop sequences.

4.5 SUPERVISORY CONTROL AND DATA ACQUISITION (SCADA) SYSTEM


Design, manufacture, testing, commissioning of the Supervisory Control and Data

Acquisition (SCADA) system which includes all equipments required for

measurement, control, metering protection data logging data recording, annunciationand sequence of event recorder, main computer, display unit with keyboard.

The SCADA system required should provide monitoring of parameters listed in

section 7.0 and control in grid mode and isolated mode operation of the Hydel Power

station centralized control room.

♦ Reliable safe control of the unit with very high availability



85

♦ Automatic startup, on-load control and shutdown of the units by the control

system

♦ Control of auxiliary equipment

♦ Remote monitoring of all plant status and alarm information

♦ Remote normal startup, on-load control and shutdown of units by operators.

SCADA system should have following controllers

♦ Unit Controller.

♦ Common Plant Controller/Supervisory Controller at Power House control

room

The SCADA system where it is proposed to be set up in this specifications shall be

designed for safe, reliable, efficient and easy operation of Hydro Turbine Generator

and its associated auxiliaries and transmission lines.

The SCADA system shall consist of a microprocessor based computer system, a

dedicated sequence of events recording system, a health/condition monitoring and

analysis system, system cabinets, local panels, sensors, local instruments, erection

hardwares, interposing relays etc.

The SCADA to be supplied shall be of proven design; operation in at least four power

house for more than 3 years and will be subject to approval by purchaser and will

consist of following.

(a) Main microprocessor based computer system.

(b) Data logger/sequence of events recorder.(c) 19” Colour graphic monitors with key boards

(d) System console

(e) Hard copy plotter/printer

(f) Complete field instruments like transmitter/transducers, sensors, interposing

relays, erection hardwares all interconnecting cables etc.

(g) Bidder shall supply all necessary software required for the SCADA system

including operating system, compiler, application software etc.

(h) The transducers required for the measurement of electrical parameters. The

output of transducers will be 4-20 mA.

The SCADA system shall be capable of performing the following functions in realtime.

a) Acquire data from primary sensors.

b) Process and retain data for each primary sensor.

c) Perform detailed thermal and vibration analysis.

d) Report machine performance in tabular and graphical format.

e) Sequence of event logging.

f) Supervisory control of auxiliaries, governing system, excitation system, circuit

breakers, including synchronising.

g) Display software including system monitoring alarm processing and display of

data, fault, and status of devices.



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h) Application software including state estimation, bad data detection, and on

line power flow.

i) Data logging and report generation.

j) Report alarms.

k) Predict need for shut down and maintenance of equipment.

l) Software shall be such that the monitoring system will take care of thetransient parameters during system run-up and shut down.

m) Software shall be modular and upgradable.

n) The SCADA software shall run in co-ordination with SCADA software for

gate control operation. It can receive data of Gate positions etc. from it and

send generation etc. data to it.

4.5.2 Response Time

Fast response time of computer system is required. Bidder will intimate following:

(a) Time duration required to update a graphical display from the instant a fieldcontact changes state.

(b) Time duration from the instant a control is activated at the operator station

until the command is implemented at the field device.

(c) Overall time duration to process and lag an alarm once it is received at the

computer.

Methodology by which these “times” were verified must be given.

Acceptable time shall be verified at the factory acceptance test.

4.5.3 Equipment Architecture and Protocol

Open architecture system shall be followed. Interface or operating standards for the

following shall be intimated and should comply with ISO/IEC 12119.

• Communications

• Operating system

• User Interface

• Data base

Each of these elements should be capable of being replaced by or communicate withsystem elements provided by other vendors.

4.5.4 Plant Operation Philosophy

The normal, start-up, shut down and emergency operations of the hydro turbine

generator, auxiliaries and feeders shall be performed in three different ways as

follows:

(i) PLC based governor control panel for unit and plant control

(ii) Control from Power House control room

(iii) Manual control panel



87

The Control Engineer shall be able to perform the following operations from the CRT

through keyboards.

a) Call up mimic, alarm, data display.

b) Call up control display to carry out control operations for hydro turbine

generators and its associated auxiliaries and main & electrical power supplysystems controlled from CRT/key board.

c) Demand, logs, report including performance calculation reports, sumaries,

trends and plots for hydro-turbine generator and its auxiliaries and main &

auxiliary electrical power supply system.

d) The control engineer shall be able to set up all pre-start check of devices from

the CRT/keyboard for unit starting such as :

1) The wicket gate control

2) The control of generator brakes

3) Power supply to the governor

4) Load/frequency device selection on speed setting mode.5) The selection of speed droop equal zero.

6) The blades at fully open position etc.

e) The control engineer shall be able to set the interlocks to start the unit from the

CRT/key board and once the start command is given following sequence shall

take place through the SCADA system.

1) The governor pump shall start.

2) When the oil pressure is established in the governor circuit, blades shall set at

the starting position.

3) Release generator brakes.

4) After having ensured that the bakes are released and blades are in starting

position command shall be given to open the wicket gates.

5) With opening of wicket gate unit speed shall rise.

6) At 90% unit speed, generator shall be excited, wicket gate shall be stopped

and its position maintained by energizing governor relays speed adjustment,

blades/movements shall be achieved.

7) When unit frequency and phase voltage is matched to that of existing power

system, unit circuit breaker shall be closed.

8) After unit breaker is connected to the system, governor parameters shall be

set to automatic mode.

f) The control engineer shall be able to shut down the unit during normal condition in

the following sequence.

1) Level control on governor shall put off

2) Blades shall close

3) When blades are closed, wicket gate shall be allowed to close.

4) When no output power is sensed unit breaker shall be tripped.

5) After unit breaker is open, blades shall open again.

6) When downstream gate is closed and unit speed is 30%, brakes, shall be

applied.



88

g) The control engineer shall also be able to trip the unit during emergency condition

with the following sequence.

1) Unit breaker shall be tripped.

2) Wicket gate shall be closed.

3) Other sequence of operation as per the normal shut down.

4.5.5 Parameter to be monitored from SCADA

The SCADA system shall be complete with all primary sensors, cables, analyzers/

transmitters, monitors, system hardware/ software and peripherals etc. to monitor/ control

the parameters for control, protection, annunciation, event recording etc different equipments

including.

• Generator stator and rotor winding temperatures.

• Lube oil temperature• Radio frequency interference

• Generator air gap monitoring.

• Acoustic levels

• Level measurement

• Turbine blade tip clearance

• Governor control monitoring of turbine speed.

• Generator terminal voltage, current, KW, KVAR, KVA, KWH,

Frequency, power factor, field voltage and field current.

• Annunciation for violation of permissible limits of the above

parameters.

• Turbine bearing temperature.

• Guide bearing temperature.

• Guide bearing oil level.

• Guide vane bearing oil temperature.

• Generator bearing temperature.

• Generator winding temperature.

• Turbine speed.

• Generator speed.

• Governor oil pumps, oil pressure indicator and low pressure switch.

• Inlet pressure gauge at inlet of turbine.

• Vacuum gauge for draft tube pressure.• Level indicator for level in the fore bay/Tailrace.

• Annunciation

Bidder shall provide suggestions relating to measurement points and sensors. If in his

opinion, an enhancement in condition monitoring capability can be attained by use of

additional sensors these should be provided and details to be indicated in the bid.

4.5.6 Hardware Requirement

The key hardware features of the controller should be as follows:



89

♦ Standardized hardware technology

♦ Highly modular design

♦ Expandable

♦ Operation over a wide voltage range

♦ Intelligent I/O modules

♦ Central and distributed I/O

♦ Communication with other controllers and computers

♦ Remote fault diagnostics

It should include all transient suppression, filtering and optical isolation necessary to

operate in a power plant environment. The type of controllers to be used in the

SCADA system should be selected to meet specific plant requirements described

below including availability, number of plant I/O, cycle time and type of

communications link. The modular design of the controllers should be such that they

are easily integrated into the control system requiring the minimum of engineering.

4.5.6.1 Unit Controller

Redundant microprocessor based/PLC based governor system control should be

interfaced with SCADA powerful enough to perform all the required functions

mentioned above. It should have capability to implement closed loop PID function for

governing. The scan time of the complete sequence for each process should be less

than 100 msec. It should have lock to prevent unauthorized modification and be

capable of detecting hardware and software failures. It may also have digital relays for

over current, over-voltage and differential generator protection. It should have

following hardware features. It should have a console and keyboard to program the

controller as well as communicate with Supervisory controller. Unit controller shouldsupport remote management and remote programming for supervisory controller.

4.5.6.2 Shut down Hardware

The controller should have a conventional relay logic shutdown circuit. This circuit

should include start and stop relays for controlling the turbine. The start relay

circuitry should provide for auto and manual control capability. A controller fail relay

should drop out the start relay when the auto relay is on. All shutdown hardware

should be powered by the station battery. The stop relay should drop the start relay

whenever a contact input which is strapped for shutdown on a digital input module is

closed.

4.5.6.3 Digital Status And Alarm Inputs

The controller should be capable of connecting to at least 60 contact type inputs

representing digital status and alarms. All contact inputs should be sensed through

optical couplers with an isolation voltage of at least 1500 Volts. The controller

should accept station battery voltage level inputs. Controller input modules should be

strappable for 24 Volt station batteries. Controller digital input modules should also

have straps to allow any contact input to cause a hardware shutdown directly to thestop relay.



90

4.5.6.4 DC Analog Inputs The controller should accept 0-1ma, 0-5V, 4-20ma or 1-5V DC analog signals. The

controller should be able to measure DC analog signals with as much as 5 volts

common mode signal with differential inputs. The controller should provide groundstraps that can be inserted on the negative lead of any input signal that should be

grounded at the controller. The controller should also provide selective terminating

resistors for 1ma and 20ma signals. The DC analog signals should be converted to

digital signals using at minimum 12 bit analog to digital converter in the controller

with all conversion errors considered the controller should maintain an accuracy of

0.1% or better of full scale and a resolution of 1 part or less in 2000. All DC analog

inputs should be protected from transient spikes and voltages with circuitry that meets

the IEEE surge withstand test.

4.5.6.5 AC current inputs

The controller should connect directly to current transformers. The controller should

accurately measure all current inputs from 0-6.25 amps. It should withstand 10 amps

continuously and 50 amps for 1 second. The controller should be able to measure

magnitude of the current with a true RMS to DC converter and its phase shift with

respect voltage. The current measuring accuracy should be to .1% and the phase shift

accuracy should be to .1 degree. The controller should induce a burden of less than

.5VA on each current transformer it connects to.

4.5.6.6 AC voltage inputs

The controller should connect directly to the potential transformers. The controller

should accurately measure voltage inputs from 80 to 150V AC. It should withstand

up to 200V AC continuously. The controller should be able to measure the magnitude

of the voltage with a true RMS to DC converter and measure the phase shift of the

voltage with respect to current. The voltage measuring accuracy should be to .1% and

the phase shift accuracy should be to .1 degree. The controller should induce a

burden of less than 1 VA in each potential transformer that it connects to.

4.5.6.7 Control outputs

The controller should provide control relays to operate the circuit breaker, voltage

regulator, and other equipment. The contacts should be DPDT rated 125 VDC at

0.5 A. Two contacts should be available from the DPDT relay and either should be

strappable as normally closed or normally open. An optional high-powered relay

should be available that provides one normally open contact rate 150 VDC at 10A.

Each relay should have an LED indicator mounted on a manual control panel to

indicate the status of the relay, on or off. Next to the indicating LED should be a

switch to operate the relay manually. Each switch/LED should be clearly marked as

to its function.



91

4.5.6.8 RTD inputs

The controller should have provisions to connect directly to RTDs. RTD readings

should be corrected for nonlinearly and readings should be accurate to + 0.25oC. The

temperature range should be 0-160oC. The controller must have a 10, 100 and 120

ohms 8 input RTD module. The correct linearizing curve should be selected byconfiguring. The controller should be capable of reading temperatures from eight

RTDs. If eight RTDs are not required, any of the RTD inputs should be able to be

used as a 4-20 mA analog input. Each of the eight inputs should be assigned three

alarm set points; two high alarm set points and one low alarm set point.

4.5.6.9 Analog outputs

The controller should output 4-20ma signals for calculated signals such as kW,

kVARS, power factor, frequency, voltage, and current. The signals should be isolated

outputs with 1000 common mode voltage capability. The accuracy of these outputsshould be better than .25%.

4.5.6.10 Alarm outputs (option)

The controller should be capable of outputting contacts for alarms that it generates

internally. The contact rating for these alarms should be 1 Amp. at 24 VDC.

All digital inputs should be capable of meeting the surge withstand capability in

accordance with ANSI/IEEE C37.90.

4.5.6.11 Electrical transducers

The controller should connect directly to current transformers (CTs) and potential

transformers (PTs). The controller should be capable of deriving the generator voltage

(line to line and line to neutral), generator amps, generator WATTS, generator VARS,

generator Power factor, generator kVA, generator frequency and bus frequency from

the CTs and PTs: The controller should be configurable for open delta (line to line)

or star (line to neutral) connected CTs and PTs.

4.5.7 Supervisory Controller

Standard Desktop Personal Computer having fast speed should be used as

Supervisory Controller and should at minimum have following configuration:

4.5.8 Speed Sensor

A speed sensor to be mounted on generator unit shaft giving output as 4 to 20 mA / 0-

5 V DC is to be provided.

4.5.9 Wicket gate position transducer



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It should comprise of LVDT mounted on hydraulic cylinder for actuating wicket gate.

It should convert linear movement of cylinder into 4-20 mA signal. 4 mA should

correspond to 0% and 20 mA to 100% stroke of the servomotor.

4.5.10 Head water/Tail water level transducer

Two level sensors, one for Headwater and one for Tail water should be provided.

4.5.11 Speed switches

Speed switches should be provided for application of brake, overspeed tripping andcreep at 30%, 112% and 5% of the rated speed respectively.4.5.12 Printers

Printer/Hard copy units must be provided with supervisory and unit controllers.

4.5.13 Recorders

The plant control system should include video recording system of selected parameters i.e.

Generator temperature etc.



item of equipment for proper location and verify the instrument/catalog number is

correct per the specification.




the drawings.


current transformers, and potential transformers.

5. Check approximately 5 to 10 percent of the internal cabling. Verify that the


• Cable numbers;



and lockout relay;




energized and the correct annunciation and/or printout occur.



93


documents.




10. PLC checks:



• Check for surge protection provided on the I/O rack and I/O cards;

• Identify grounding connections for the PLC and the I/O rack; determine





•

Verify that modem connections are provided and functional.






schemes);



• Automatic emergency stop sequence (usually performed by activating oneof the lockout relays while in the “normal running” mode );



- Local control to remote control

- Remote control to local control






• Verify the performance of the automatic synchronizing circuit and the

manual sync-check relay (if provided).






• Terminal block designations; and• Raceway layouts



94





controlled from the UCS to verify proper operation.7. Perform functional checks on unit start/stop sequences, duplicating the factory

sequences. These checks should be performed first with the associated power


8. Methodically document steps 1 through 7 to ensure that no cables, instrumentation

devices, protective relays, or control systems have been overlooked.


4.5.16 Additional Factory and Field Tests for Distributed Control Systems

1. Point-by-point database check.

2. Database linkage to graphical displays.3. Response times during normal loading and high activity loading scenarios for:

• Graphical display updates;

• Control sequence implementation;

• Alarm processing and logging; and

• Sequence of events recording

4. Communications connectivity/protocols.

5. Man-machine interface (MMI) user capabilities.

6. Application software functionality.

4.5.17 Data/ Document to be furnished by the Bidder

Bidder shall furnish the following data/documents with the Bid.

♦ All technical parameters such as baud rate, frequency, memory capacity

input/output capacity of modules expansion capacity of the SCADA system,

etc.

♦ Input/ Output list.

♦ List of parameters to be monitored from CRT/key board and the details of the

same.

♦ Redundancy provided for any of the equipment.♦ List of application software.

♦ Bill of material

♦ Price schedule as per the enclosed schedule.

♦ Type of Cables.

♦ List of essential spares.

♦ Experience list.

♦ Manual/ catalogues of every equipment supplied by him.

♦ Plant operation philosophy.



95

SECTION -V

TECHNICAL SPECIFICATION FOR

CONTROL PROTECTION, METERING AND

SUPERVISORY CONTROL AND DATA ACQUISITION SYSTEM

(SCADA)

(FOR SHP OF ABOVE 5 MW TO 25 MW CAPACITY)

5.0 SCOPE

The Contractor shall design, fabricate, assemble, test at manufacturers’ works, supply,

deliver, erect, test at site, Commission and train owner’s operating personnel for the

Control, Protection and Monitoring Equipment and System for power generation,

transformation and transmission and comprising of following.

A Manual (conventional) Control and Protection System.

(iii) Unit control, metering and protection relay panels (For each unit).

(iv) --- kV Feeders control, metering and Protective relay panels.(v) --- kV Bus coupler control and relay panel.

B Supervisory Control and Data Acquisition Equipment

(i) Redundant Personal Computer/Mini computer based SCADA for supervisory

control

(ii) Offsite supervisory control and data acquisition. The SCADA equipment will

be provided in the centralized control room of offsite station.

(iii) A programming and training console at centralized control room

.

C. Communication Link

(i) Dedicated communication system between control room to off-site control

centre alongwith terminal equipment for control and local area network for

distributed control and for voice communication.

(ii) Voice communication between control room, interlinking grid substation and

offsite centralized control room.

5.1 APPLICABLE STANDARD

1. ANS/IEEE 1010 – 1987 – IEEE Guide for Control of Hydroelectric

Power Plants2. IS/IEC/ISO Standard Mentioned in Text



96

5.2 CONTROL AND MONITORING SYSTEM

General Considerations

Considerations involved in providing control and monitoring systems for the power plant and the switchyard are as follows:

h) Main Single Line Diagram is shown in drawing (to be enclosed by Purchaser);

Metering and Relaying as proposed is shown in drawings(to be enclosed by

Purchaser);

i) The power house is proposed to be controlled by supervisory control from

control room of powerhouse as well as from offsite control centre.

Accordingly provision is to be made for manual and automatic control for unit

starting, unit stopping and running control at the power house with provisionfor supervisory control and data acquisition at power house as well as in

centralized offsite control room.

j) Dependable digital controls for system control with conventional manual

control as backup are proposed.

k) Power house units operation and loading is proposed to be Canal/HRC water

level controlled

l) The turbines, generators, transformer and other equipment proposed for the

unit will be provided with necessary sensors and actuators. Intake gates/MIV

with capability of gravity closing under emergency shall also be provided on

upstream side.

m) Emergency conditions (power house unit tripping etc.) will be taken care of byoperating regulating Bypass Gates. For this purpose suitable provisions will be

made in the control.

n) The generators are proposed to be provided with static excitation system.

o) ---- number 11/--- kV unit transformers of --- MVA capacity each are

proposed to step up the generated power to --- kV.

p) A single sectionalised --- kV bus is proposed for reliability.

k) Entire power is to be fed into --- kV grid as shown in enclosed drawing.

The scheme will be designed in accordance with ANS/IEEE – 1010 and will be

subject to approval by owner.

5.3CONTROL AND MONITORING OF PLANT EQUIPMENT

5.3.1General

The control system shall receive input signals from main equipment such as the

turbine or the generator, and from various other equipment, such as the governor,

exciter, etc. Status inputs shall be obtained from control switches, level and function

switches indicative of pressure, position etc, throughout the plant. The proper

combination of these inputs to the control system logic will provide outputs to the

governor, the exciter, and other equipment to start or shutdown the unit. Anyabnormalities in the inputs must prevent the unit’s startup, or if already on-line,



97

provide an alarm or initiate its shutdown, depending upon the magnitude of

abnormality.

The unit control boards should be designed to perform the following functions:

(ii) Information receipt and monitoring(viii) Start/stop sequencing control

(ix) Annunciation of alarm conditions

(x) Temperature information monitoring

(xi) Metering and instrumentation signals display

(xii) Event recording, when required

(xiii) Synchronizing and connecting the unit to the system

The unit control board is the central control means and communicates with the main

and associated equipment through hard wire or multiplexing.

5.3.1.1 Level Controlled Operation of Power Units :

The power units operation is proposed to be level controlled so that in case of variation in

canal/HRC water level due to discharge variation, loading on the power units is

automatically adjusted to available water and energy output is optimised, unnecessary

gate operation avoided and canal water level maintained between permissible limits.

Redundant level monitoring system – one float operated and the other non float operated

shall be provided.

5.3.1.2 --- kV line Control

Manual control of the --- kV SF6 breaker is proposed in the power house and supervisory

control in the centralized control room as well as at offsite control centre.


The unit auxiliaries are proposed to be provided automatic control to suit the unit control

as proposed for manual/supervisory control centralized control room and offsite control.

5.3.1.4 Annunciation

Annunciation system is proposed to be designed for control of the unit from the

powerhouse as well as supervisory control in centralized control and offsite control. The

normal annunciators consisting of indicating lamp and relay assembly is proposed to be

provided on the unit control boards in the power house. The remote annunciation for

supervisory control will be part of digital control system.

Data logging – Data will be stored in hard disc and printed every half an hour for which

printer will be provide at centralized control room as well as off-site.



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5.3.1.5 Auxiliaries Control

Centralized controls of the power distribution and control boards is proposed for

unattended automatic operation and for remote control from power house no. 4.

Automatic switching of selected standby and emergency auxiliaries on failure of running

auxiliaries is proposed. Automatic change over of entire unit auxiliaries to alternate

source of supply is also proposed.

5.3.1.6 Switchgear and Motors

Air break switchgear is proposed to reduce fire hazard. The opening/closing time of

switchgear may not exceed 8 cycles so that stalling of motors on change over does not

take place. All motors are direct on line starting and are therefore high starting torque.

5.3.2 Control and Status Data

Control and status data to be transmitted from various equipment to Unit Control

Board and from Unit Control Board to the equipment etc is detailed below. This is

tentative and may be increased or decreased as required with owner’s approval.

Information and control signals will be needed between the control board and each of the

following:

Canal/HRC water levelTurbine Table – 5.1.1 to 5.1.3

Turbine speed governor Table – 5.2.1 to 5.2.3

Generator Table – 5.3.1 to 5.3.7

Generator excitation system Table – 5.4.1 to 5.4.3

Unit transformer Table – 5.5.1 to 5.5.3

Circuit breaker and switches Table – 5.6.1 to 5.6.2

Intake gate/MIV and draft gate Table - 5.7

Additionally, control signal shall also be from Auxiliary equipment, Fire Protection,

Auxiliary AC Power Supply, DC Power supply, Service Water, Service Air shall be

provided as per IEEE – 1010.

These equipment blocks represent auxiliary service equipment needed for the proper

operation of the generating plant. Abnormal conditions of this equipment will be alarmed.



99

Table- 5 .1 .1 - Control and Status Data Transmitted form Turbine to

Unit Control Switchboard


38TG Turbine guide bearing

temperature

T,A,P,I Temperature detectors, Provision

for mounting two sensors in

bearing shell.

38QTG Turbine guide bearing oil

temperature

T,A,P,I Temperature detector in bearing oil

reservoir.

71QTGH Turbine guide bearing oil

level high



.

71QTGL Turbine guide bearing oil

level low



39 TV Bearing / shaft vibration

detector

A,P Vibration probes installed on guide

bearing housing at 90º. to each

other, for detection of excessive

bearing and shaft vibrations. Used

in conjunction with probes on

generator guide bearing.

33SP Wicked gate shear pin

failure

A Shear pin failure while closing

wicket gates due to obstruction

80WB Bearing cooling water low

flow

A Pump failure, obstructed piping or

pipe rupture.

71WTH Turbine pit water high level A, C Senses excessive water level in

turbine pit due to plugged drains or

major seal failure. One contact

operates submersible pump.

63AMS Turbine shaft air

maintenance seal applied

A, P Contact blocks unit startup and

initiates shutdown if seal appliedduring running

SCWP Water pressure in Intake P, I Direct reading on transducer

operated gauge.

Unit startup interlock, shutdown if

loss of pressure in running unit

DTWP Draft tube water pressure-

vaccum

I Direct reading on transducer

operated gauge

48TG Turbine greasing system

failure ( if greasing systemprovided )

A Alarm if lubrication cycle not

completed



100

74TG Turbine greasing system low

voltage( if greasing system

provided )

A Detects failure of power supply to

solenoid valve used to control

greasing cycle.

Wicket Gate Servomotor

Position


system.

Runner Blade Servomotor

Position


system.

TYPE C = Control

P = Protection Trip


T = Temperature MonitoringI = Indication (analog, digital, status lamps)

NOTE – Wicket gate automatic lock functions are described in section 3H

Table- 5 .1 .2 - Control and Status Data Transmitted fr om Unit Control

Switchboard to Turbine


1GS Turbine grease system

Start/Stop (if greasing

system provided)

C Enables grease system

when unit is running.

1TL Turbine lube oil sys tem

start /s top

C Enable turbine

lubrication prior to unit

run.

Type

C = Control

P = Protection Trip

A = Annunciat ion/Event Recording





101

Table-5.1.3 - Operating Power, Air and Water from Service Equipment to Turbine


Power supply for control and protection

devices

DC

Power supply for turbine pit water pump AC

Air supply for shaft maintenance seal. A

Water supply for bearing oil coolers and

turbines seals

W

Power supply for Lubricating oil system

for bearing

AC May be alternately fed from

DC.

Type

AC = AC Power

DC = DC Power

A = Air

W = Water

Table 5.2.1 – Control and Status Data Transmitted from Governor to Unit ControlSwitchboard


N Speed indication I Methods of developing the speed signal include

the following :

- Hall-effect, eddy current, magneticsensors operated in conjunction with

toothed wheels or other devices directly

connected to the generator shaft (speed

signal generator – SSG)

- Voltage transformers connected to the

generator output leads must be capable of

operating at very low residual voltages in

absence of field excitation

12-X Over-speed C, P Over-Speed Switch should be actuated

mechanically by means of a centrifugal device

mounted on the turbine shaft.12-X1 Over-speed, C, P Electrically actuated speed relays by comparing



102

13-X

14-X

Synchronous

speed and under

speed switches

the speed signal to a reference signal

65SF Speed signal

failure

A,C,P Loss of speed signal may initiate control action

i.e. shutdown of the unit and annunciation.

39C Creep detector

operation

A,C Control action upon detection of shaft movement

after shutdown may include any or all of the

following :

- Start thrust/guide bearing HP oil pump

- Release brakes

- Drop intake gates

- Alarm

- Start turbine guide bearing oil pump

65Ss Start/stop solenoid

auxiliary contacts

or gate limiter

limit switches

C,I Provides information of starting /stopping

process.

65SNL Speed-no-load

solenoid aux.

contacts or gate

position

C,I Provides confirmation of 65SNL operation. Used

to seal in remote controls and provide remote

indication.

WG Wicket gateposition indication C, I Typically derived from potentiometer or LVDTcoupled to restoring connection from wicket gate

servomotor.

33WG Wicket gate

position switches

C,P,I Typical uses of gate position switches for control

and indication:

- Generator brake application (that is, apply

brakes at low speed if gates at 0%)

- Turbine gate lock (apply at 0% gate

position)

- Trip generator breaker as gates pass

through speed-no-load position (auto-stop,protective shutdowns without overspeed)

- Incomplete stop detection

- Unit running detection

- Initiate time delay for stopping auxiliaries

- Reenergize starting relays to provide

restart after momentary loss of power

71 QP Governor Oil

Pressure Unit – oil

level switches in

Pressure Vessel

A, P Alarms for high, low and extreme low levels.

Shutdown for extreme low level, air admission

for high level.



103

63Q Governor Oil

Pressure Unit -

pressure switches

on Pressure Vessel

A, P Pump control, alarms for low, and extreme low

pressures, shutdown for extreme low pressure.

71 QS Governor OilPressure Unit –

level switches for

oil level in sump

tank

A Alarms for high and low oil levels.

26QS Governor Oil

Pressure Unit –

sump tank oil

temperature high

A Indicative of excessive governor action.

6Q Governor Oil

Pressure Unit –

standby pump

operation

A Indicative of excessive governor action or pump

failure

27PS Governor power

supply failure

A,C,P Indicates failure of input AC or DC power or

failure of regulated DC power supplies. May

result in unit shutdown depending upon level of

power supply redundancy.

63AB Generator airbrakes applied C,I Indication and auto-start interlock.

63AB

S

Generator air

brake supply

pressure low

A

33WG

L

Wicket gate

automatic lock

applied/released

C, I Indicates status of the gate lock (applied on

shutdown when gates at 0%).

65WGLF

Wicket gateautomatic lock

failure

A Indicates that the gate lock has not been fullyapplied on shutdown.

65M/L

S

Manual control

indication

I Provides remote indication that the governor is in

manual control at the governor cubicle.

63QP

V

Pilot valve strainer

obstruction

A Alarm for attending strainer

49F Fire detection

system

operation/trouble

A,P Operation or failure of detection/ extinguishing

system.



104

BAL Governor balance

indication

I For electric governors, indication of electric-

hydraulic transducer input voltage.

Type

C = Control

P = Protection trip




Table 5.2.2 – Control and Status Data Transmitted from Unit Control Switchboard

to Governor


39 Creep detector

enable

C Enables rotor creep detector after a fixed time

following application of brakes on shutdown.

15FR,

15FL

Speed reference

raise /lower

commands

C Typically relay or switch contact closures. If power

reference also provided, speed raise/lower operable

only off-line. Some installations may utilize input

reference analog or digital signal rather than raise /

lower commands.

65PR,65PL

Powerreference raise

/lower

commands

C Typically relay contact closures when unit on –line.Some installations may utilize input reference

analog or digital signal rather than raise/ lower

commands.

65GLR, Gate limit

raise/lower

commands

C Typically relay contact closures, route to reversing

drive motor. Primary function of the gate limit (GL)

is to limit the maximum opening of the wicket gates

under operator control to prevent overloading the

unit at the prevailing head. Other control and

protection applications include:

- Pre- positioning GL to 0%prior to starting to

permit controlled opening of the gates upon

energization of the start / stop solenoid

65SS

- Raising GL to turbine breakaway gate

position after energization of 65SS

- Rapid unloading of the machine during

certain stop and protection shutdown

sequences



105

3SS On-off

command to

start/stop

solenoid 65SS

or gate limiter

motor

C,P The start/stop solenoid 65SS typically operates as

follows :

- Energized to allow wicket gates to open and

close under control of the electric governor,

gate limit or manual gate control, that is,

“energized to start and run”- De-energized to initiate complete closure of

the wicket gates at maximum rate and block

subsequent opening of the gates, i.e. “de-

energized to stop”

Typical functions that will block start and/or initiate

stop are

- Unit protection operation (includes all

electrical and mechanical fault detectors that

initiate shutdown of the unit)

- Operator-initiated stop- Generator thrust bearing high pressure oil

pump failed to achieve full pressure

- Turbine shaft maintenance seal on or low

gland water flow.

- Generator brake shoes not cleared or brake

air pressure not off, or both.

- Intake gate not fully open

- Generator and turbine bearing cooling water

not available.

- Wicket gate lock not released

3SNL On/off

command to

partial

shutdown

(speed-no-load)

solenoid

C,P The partial shutdown solenoid 65SNL (if used) is

typically de-energized to limit the opening of the

wicket gates, or return them, to a position slightly

above the speed-no-load position and is controlled

as follows :

- Energized when unit circuit breaker closes

to allow generator to be loaded.

- De-energized whenever unit circuit breaker

trips to restore unit to near rated speed;

provides backup to the electric governor

- De-energized to unload the unit for certain

protection operations (that is over speed to

112% during opening of unit circuit breaker)

V, I Generator

voltage and

current

C Inputs to power transducer (for governors utilizing

power feedback rather than gate feedback).

52 Unit on-line C Generator circuit breaker auxiliary contact. Used to

switch between on-line and off-line gains incompensation circuits (PID) and to switch between



106

speed and power references.

3AB Generator air

brakes on/off

command

C Air brakes automatically applied on shutdown if

wicket gates close and speed below a predetermined

level.

71NH Level

difference

between

headwater and

tail water

C Used for optimum turbine blade positioning and

optimum gate position/ power generation.

Type

C = Control

P = Protection Trip




Table 5.2.3 – Operating Power, Air and Water from Service Equipment to

Governor


Power supply for DC control DC One or more separate supplies depending on

power distribution arrangement

Power supply for Oil Pressure

Unit pumps

AC One or more separate supplies depending on

number of pumps and required redundancy.

Alternate supply for governor

power supplies

AC

Air supply for generator air

brakes

A -

Air supply for Oil Pressure Unit A

Cooling water for Oil Pressure

Unit oil sump

W (Optional)



107

Type

AC = AC Power

DC = DC PowerA = Air

W = Water



108

Table 5 .3 .1 – Control and status data Transmitted from Generator to

unit control board


26GS

38THT

38GT

38QB

26AO

26AI

26GF

71QBH

71QBL

Stator winding

temperature

Thrust bearing

temperature

Guide bearing

temperature.

Bearing oil

temperature

Air cooler outlet air

temperature.

Air cooler inlet air

temperature.

Generator field

temperature.

Bearing oil level high

Bearing oil level low

T,A,P

T, A, P

T, A, P

T, A, P

T, A

T, A

T, A, P

A

A

Temperature detectors (typically 12)

embedded in stator winding accordance

with ANSI C50. 10-1977 (1). Two hottest

RTDs connected to thermal overload relay

49G.

Temperature detectors embedded in wells in

the shoes or segments with provision for

interchanging sensors between segments.

Temperature detectors. Provision for

mounting sensors in all segments.

Temperature detectors in bearing oil

reservoir.

Temperature detectors. (Quantity dependent

on number of coolers and desired level of

coverage.)

Temperature detectors. (Quantity dependent

on number of coolers and desired level of

coverage.)

Temperature monitoring system for

continuously monitoring field temperature.

One sensor for oil reservoir, equipped with

direct reading visual indicator.

One sensor for each separate oil reservoir,equipped with direct reading visual

indicator.

38QW

39V

Bearing water

contamination

detector

Bearing/shaft

vibration detector

A

A. P.

One sensor for each separate oil reservoir,

for detection of water buildup or emulsified.

Eddy current probes installed in guide-

bearing segments at 90 degrees to each

other, for detection of equipment defectsand rough zone operation. Used in



109

63QTH Thrust bearing high

pressure oil system

start interlock/failure

alarm.

C, A, I

conjunction with probes on turbine guide

bearing.

Pressure switch provides confirmation that

the oil pump motor has established

sufficient pressure to allow the start

sequence to proceed. Used also to generatealarm if pressure fail to establish after pump

is commanded to start.

26G

63FG

33AB

CT-G

33CW or

80CW

Temperature

detectors for fire

protection system

Fire extinguishingsystem operation

Air brake position

indication

Neutral end and

terminal end current

transformers

Cooling water valve

position

Cooling water flow

low

P, C, A

P, A

C, I

P, I

C, I

A, P

Fixed temperature or rate-of-rise of

temperature or both; detectors mounted in

stator end turn area. Used to initiate fire

extinguishing system in conjunction with

fault detecting equipment.

Pressure switches installed downstream of actuating valve. Back trip generator

protection. May also be used to generate an

extinguishing system failure alarm if system

is initiated but pressure fails to establish

within a fixed time.

Start interlock indicating all brake shoes

have cleared runner plate.

Furnished in quantities and ratings

compatible with the metering and

primary/standby protection requirements.

Start interlock and status indication.

Pump Failure, supply valve closed, pipe

obstruction, pipe rupture

TYPEC = Control

P = Protection trip






110

Table 5 .3 .2 – Control and status data Transmitted from Generator to

unit controlbord


2THS

20CWS

20FGS

20AL

1GL

Thrust bearing high

pressure oil pump start/

stop command.

Generator cooling water

system start/ stop

command.

Fire extinguishing systemoperate command.

Air louver operate

command

Generator lube oil system

start/stop command.

C

C

C, P

C, P

C

Start pump prior to starting unit.

Confirmation of pump starting via 63QTH

(Table 3A-1)

Open valve or start pump prior to starting

unit. Confirmation of water flow via 33CW

or 80CW (Table 3A-1).

Open valve upon detection of fault +excessive heat. Confirmation of valve

operation via 63Fg (Table 3A-1).

Close discharge and inlet air louvers in

generator housing in event of a fire.

Enables generator lubrication prior to unit

run.

When forced air cooling is used for the

generator.

Turned off when unit is on-line.

TYPE

C = Control

P = Protection trip






111

Table 5 .3 .3 – Operating Power, Air and Water from Service Equipment

to Generator


Power supply for thrust bearing high-

pressure oil pump.

Power supply for DC control circuits.

Air supply for brakes and rotor jackingsystem


system

Power supply for generator housing

space heaters.

Water supply for generator air coolers

and bearing oil coolers.

Air supply for operating discharge and

inlet air louvers

Power supply for CO2 fire extinguishing

system.

Power supply for generator lube oil

system.

AC

DC

A

W

AC

W

A

DC

AC

415 volts 3 phase AC.

For uninterruptible systems such as air

cooler temperature control system, fire

protection.

Control valve may be located in governorcubicle/ generator brake panel.

May also be atomized.

Thermostatically controlled, for reducing

condensation on windings when generator is

shut down.

May be fed alternatively from DC source.

TYPE

C = Control

P = Protection trip






112

Table 5.3.4 – Control and Status Data Transmitted from Generator Terminal

Equipment to Unit Control Switchboard

SignalDescription Type Notes


metering

VT Voltage signal for relaying and

metering

A Current indication I

F Frequency indication I

V Voltage indication I

W/VAR Metering I,A Analog signals forindication and/or recording.

AVR Voltage signal for automatic voltage

regulator (AVR)

C Analog signal from a VT.

N Governor speed sensing C

XDCR Power transducer C Unit power input to electric

governor.

TYPE

C = Control

P = Protection Trip



I = Indication analog, digital, status

lamps)



113

Table 5.3.5 – Control and Status Data Transmitted from Unit Control Switchboard

to Generator Terminal Equipment


20 Fire extinguishing system

command

C,P Deluge valve upon differential

operation and high temperature

detection.

TYPE

C = Control

P = Protection Trip




Table 5.3.6 – Operating Power, Air and Water from Service Equipment to

Generator Terminal Equipment

Description Type Notes

Power supply from DC control circuits DC For uninterruptible systems such as

fire protection.

Power supply for forced air bus duct

circulation system

AC


system and forced air cooling

W

TYPE

AC = AC Power

DC = DC PowerA = AirW = Water



114

Table 5.3.7- Control and Status Data Transmitted to and from the Cooling System

and Unit Control System

Description Type Notes

Conventional

Fan failure A.P. Trip occurs on multiple fan failures

resulting in insufficient air flow

Raw water low flow A Trip is accomplished by winding

temperature

Strainer differential pressure A

Type

A = Annunciation

C = Control

P = protective trip

T = temperature monitoring



115


51ET Exciter transformer o/c

protection

P

49 GF Field overload 1 Set to coordinate with field winding thermal

characteristic

I f Field voltage indication 1 Transuded from DCCT ( satiable reactor )

Vf Field voltage indication 1

64 F Field ground detection P or

A

27 FF Failure of preferred field

flashing source

A Provision of this alarm assumes 2 sources

provided AC and DC. AC should be

preferred source to minimize chance of back

feeding field voltage onto battery if blocking

diode fails. Automatic transfer to alternate

source on failure of preferred source

41/a,

41/b

Field breaker position C,I

31/1,

31/b

Field flashing contactor position I

48E Exciter start sequence

incomplete

P,A Set to operate after normal time required for

field flash source to build terminal voltage to

level sufficient for exciter getting to

commence.

78 E Pole slip protection P

63F-1 Cooling fan failure –Stage I A Failure of redundant fan (s).

63F-2 Cooling fan failure –Stage 2 P

27PS DC power supply failure P or

A

Trip or alarm depending on level of power

supply redundancy.

26ET-I Exciter transformer over

temperature –Stage I

A Indicating unit with dial contacts typical.

Table 5 .4 .1 – Control and Status Data Transmitted from excitation system

to unit control switchboard



116

26ET-2 Exciter transformer temperature

–Stage 2

P

58-1 Rectifier transformer

temperature

A Thyristor fuse, conduction, or gating failure.

-58-2 Rectifier failure –Stage 2 P

49 HE Heat exchanger failure A Various heat exchanger arrangements are

possible Once-through, closed system, etc

26RTD Exciter transformer temperature

indication

I Temperature detectors. Quantity variable

depending on number of secondary winding

and whether transformer is 3 phase or 3 x 1

phase.

70V Manual voltage adjuster with I Signal generated by potentiometer coupled to

70V motor drive.

70V/LSI,

2

70V End-of travel indication I Signal generated by limit switches coupled to

70V motor drive

90V Auto voltage adjuster with

position

I Same as 70V.

90V/LSI,

2

90 V End-of –travel indication I Same as 70V/LSI,2.

70V/LS3 70V preset position C Interlock in start sequence

90V/LS3 90V preset position C Interlock in start sequence.

89LS Station service A.C test supply

switch position

I Optional

MAN Indication mismatch between

auto

I To ensure bumpless transfer from AUTO to

AUTO Voltage regulator output and

manual

I MAN and MAN to AUTO





117

TYPE

C = Control

P = Protect ion TripA = Annunciation /Event recording

T= temperature Monitoring


Table 5.4.2 – Control and Status Data transmitted from unit control Switchboard

to excitation


41

protective

trips

Field tripping from generator P

41 control Field breaker tripping from

manual control and unit

shutdown sequence logic

C

41 close Field breaker closing from

manual control and unit start

sequence logic

C

IE Exciter de-excite C Close contact to initate field

flashing at 95% speed during

auto start or under manual

control

IE Exciter de-excite C Open contact to initiate

phaseback below 95% speed,

unit separated form system

83VT Voltage transformer potentil C Transfer exciter from auto

voltage control to manual

control

43AM Close contact transfer exciter

to manual voltage regulator

control

C

43VA Close contact to transfer

exciter to auto voltage

regulator control

C

70V Rum.

Back logic



C

90V Rum.

Back logic



C

70 V raise Raise manual voltageadjuster

C



118

70 V lower Lower manual voltage

adjuster

C

90 V raise Raise auto voltage adjuster C

90 V lower Lower auto voltage adjuster C

52G/a Generator CB Auxiliary

switch

C De- excite control, disable

power system stabilizer of-line.

Wicket

gate

position

Analog signal representing

wicket

C Used to develop accelerating

power input to PSS if required

TYPE

C = Control

P = Protect ion Trip

A = Annunciation /Event recordingT = temperature Monitoring




119

Table 5.4.3– Operating Power, Air and Water from Service Equipment to

Excitation system


Station service as test supply AC Used for exciter testing and emergency

operation if exciter transformer out of service

(optional)

Battery-fed field flashing DC

Station service field flashing

source

AC AC preferred source. Auto transfer to dc if ac

not available

Cooling water supply for

heat exchanger

W

TYPE

C = Control

P = Protect ion TripA = Annunciation /Event recording





120

Table 5 .5 .1 – Control and Status Data Transmitted from

Transformer to Unit Control Switchboard



metering

A, P, I

71G Gas accumulation detection A Event recording (optional).

63G Gas pressure device A, P Event recording

63Q Main tank sudden pressure relief

device

A, P Hand reset contact (local). Event

recording

63T Main tank over pressure switch A, P Trip generator breaker

49-1W

49-2W

Transformer winding temperature

thermal device in each separate

winding

A, T, P Temperature detectors embedded

in each separate winding for first

stage temperature control. RTD

are in each winding because of

the possibility of unbalanced

loading.

26Q Top oil temperature indicator A, T Dial type oil temperature

indicator at the transformer. First

stage annunciation, tripping

optional. Second stage tripping

71QC Conservator tank oil level indicator A Dial type indicator withmaximum and minimum

indicating levels. Tripping

optional.

Table 5.5.2 – Control and Status Data transmitted from UnitControl Switchboard to Transformer


20 Fire extinguishing systemcommand

C, P Actuated upon differential relayoperation or sudden pressure relief

device. Fire detection sensors shut off

the transformer fan and pumps

Type

C =Control






121

Table 5 .5 .3 – Operating Power, Air and Water from Service Equipment

to transformer


Power supply for DC control

circuits

DC For uninterruptible systems such as fire

protection.

Power supply for fans, pumps,

ac control circuits

AC For FA, FOA transformers. If an FOW

transformer is used, additional

information and control signals may be

needed, such as monitoring of the

pressure difference between the oil and

water systems.

Water supply for fire

extinguishing system

W

Water supply for cooling W

TypeAC =AC Power

DC =DC PowerA =Air

W =Water

Table 5 .6 .1 – Signals Transmitted from Plant Equipment to Generator

Breaker

Signal Description Type

Notes

4 Unit control C Normal shutdown

1XJ Breaker control switch, trip/close C

12G Generator overspeed P

25 Synchronizing equipment C

33 Wicket gate position switch C Permissive switch

38GB Generator bearing temperature P

38TB Turbine bearing temperature P

43XJ Breaker test switch C

49T Step-up transformer over temperature P

63T Step-up transformer sudden pressure P

71K Kaplan low oil P

80TBQ Turbine bearing oil P

38G Generator winding temperature P

43S Unit synchronizing selector switch C Permissive switch



122

Table 5 .6 .2 – Signals Transmitted from generator Br eaker to Unit

Control Switchboard


52a, b Breaker open-close C, I

27CB Generator breaker loss of dc control

power

A

61 Generator breaker pole failure P, A Trip is isolate breaker.

63a Breaker air pressure switch C Permissive switch.

63A Generator breaker low air pressure P, A

TypeC =Control




Table 5.7 – Intake Gate/MIV and Draft Gate Controls for automatic operation of the Intake gate shall as follows:

1 Unit Control Board • Raise/lower control switch

• Indicating lights for fully open/fully

• Position indication showing actual position

of the gate

2 Local • Raise/lower control switch

• Mechanical device showing gate position

3 Annunciation • Failure of gate to open or close in response to

an automatic signal

• Failure of gate to maintain partial closure

position during sluice operation

• Hydraulic system trouble

Table 5 .8 – Canal/HRC Water Level Signal f or Governor Control

S. No. Description TypeNotes

1 Breaker open-close C, I,P

2 Generator breaker loss of dc control

power

C,I



123

5.4 MANUAL CONTROL, METERING AND PROTECTION SYSTEM


Design, manufacture, testing, commissioning of manual control, metering and protection system which includes Electrical protection by conventional relay; manual control and metering of the Power House.

5.4.2 Standards

All materials and equipments shall comply in every respect with the requirements of the

latest edition of the relevant Indian, British equivalent N.E. M.A. I.E.C. Standards or any

other recognized International standards, except in so far as modified by this

specification. Where standards offered are other than the Indian or British standards,copies of the relevant standard specification in English language must be attached.

5.4.3 Design Criteria

The control will have provision for start, stop, manual synchronizing and emergency stop.

Sequencing will be as following tentative Drawings (to be enclosed by Purchaser).

• Start Sequence for synchronous generator

•

Normal Stop and Mechanical Trouble Stop Sequence forSynchronous Generator

• Electrical Trouble Stop Sequence for Synchronous Generator

Final drawings will be submitted for approval by the Purchaser



various relays are explained in following tentative drawings (to be enclosed by

Purchaser).

i. Single Line Diagram Main

ii. Metering and Relaying Single Line Diagram (sheet 1 of 2)

iii. Metering and Relaying Single Line Diagram (sheet 2 of 2)

iv Unit tripping and annunciation block diagram

Common tripping relays for similar functions have been provided with lock-out

facilities. All these relays shall have potential free contacts for trip and alarm purposes

and externally hand reset type of flag indicators. They should preferable be housed in

drawout type of cases with tropical finish.

All the protective equipment will be housed in the Power Plant main control room.The details of C.T.’s for all the unit protection and metering are given in Drawings



124

No. ----. The secondary current of C.T.’s located in switchyard is proposed as 1 amp.

because of long leads so as to ensure efficient and accurate operation of their

protective scheme.

11 kV C.T.s and P.T. may be mounted on 11 kV switchgear panels alongwith relays.

The drawings for the proposed system will be subject to approval by the Purchaser.

5.4.5 Protective Relays

A brief description of protective relay proposed is given below:

5.4.5.1 Generator Protection

Generator Differential Protection (87G)

The generator primary protection is proposed by high impedance type of

circulating current relays having proper setting range. The relays will be of

high speed type and shall be immune to A.C. transients. Necessary provision

shall be made in the relay to ensure that the relays do not operate for faults

external to the protected zone. The relays shall not maloperate due to

harmonics in spill current produced by through faults or due to saturation on

one set of current transformers during an external fault. Provision shall also be

made for alarm /indication in case of current transformer secondary circuit

fault.

The relay operation actuates lockout relay for complete shutdown of the unit

including release of CO2 as shown in Drawing No. ----.

Generator ground fault protection (64G)

The generator neutral will be earthed through the primary winding of a

distribution transformer of proper capacity and ratio. The secondary will be

loaded by a suitable resistor rated for 60 seconds. A suitable voltage relay with

continuous coil rating with proper setting is proposed to be provided. Therelay shall be insensitive to voltage at third harmonic frequencies.

The relay operation actuates lockout relay for complete shutdown of the unit.

Neutral Grounding Transformer and Loading Resistor

Neutral Grounding Transformera. Type Dry type, Natural air cooled,



125

single phase.

b. Connection Between generator neutral

and ground

Loading Resistor

a. Construction Non-ageing, corrosion

resistant, punched stainlesssteel grid elements provided

with necessary installations,

and temperature rise not

exceeding 300 deg. C.

b. Housing Enclosure with IP:22 degree

of protection. However,

transformer and resistor can

be housed in same container

with metallic partition.

Generator over-voltage protection (59)

A set of single phase relays is proposed with suitable time delay setting so that

operation of relay under transient conditions is avoided. The relay setting

range is proposed from 110% to 150%. The relays shall be immune to

frequency variation. Provision of instantaneous tripping element at some

suitable setting is also proposed.

The relay is set to operate lockout relay for partial shutdown to speed no load

position.

Negative phase sequence current protection (46)

A two stage protection complete with filter network is proposed for this

purpose. The first stage with a lower suitable range shall be instantaneous and

shall be arranged to give alarm and annunciation and the second stage with

higher range will energise a timer which shall perform the various tripping

functions in two stages at different time settings, as shown in the drawing E-

230-3. The current transformer for this protection is proposed to be located on

the generator line side.

The relay is set to operate the lockout relay for partial shutdown to speed noload position.

Voltage restraint over current protection (51V)

This backup protection for the generator operates for over current which are

accompanied by dip in voltage so that false tripping due to through faults are

avoided. The relay is set to trip lockout relay for partial shutdown to speed no

load position.



126

Reverse power relay (32)

This relay is proposed because of grid connection. The relay is proposed to be

set to trip lockout relay to speed no load position.

Check Synchronising relay (25)

Check synchronising relay is provided to ensure the closing of the circuit

breakers on synchronising at a phase angle not greater than about 7 degrees so

as to prevent damage to circuit breaker especially in case of auto

synchronising.

Potential transformer fuse failure protection (60)

Suitable voltage balance relays are proposed to monitor the fuse failure of 3

sets of potential transformers and to block the relays (50/51 V or 40) or otherdevices that may operate incorrectly on the voltage due to fuse failure of

potential transformers. The relay is set to give an alarm only.

Mechanical Protections

Following mechanical protections are proposed for the generator:

j. Resistance temperature detectors in stator core (12 no.) and in the

bearings for indication, alarm and recording. RTD’s are to be provided

by Generator Suppliers.

k. Turbine and generator bearing, metal and oil temperatures –

alarm/shutdown.

l. Governor oil pressure low to block starting and low-low for emergency

tripping.

m. Over speed for normal and emergency shutdown depending upon its

extent.

n. Signal to canal regulating gates to avoid channel overtopping due to

emergency shut down of unit.

o. Contractor will co-ordinate with Generator and Turbine supplier for

mechanical protection.

5.4.5.2 Exciter Protection

Generator field failure protection (40)

An offset mho type of relay having its circular characteristics adjustable both

in offset and diameter, along the X-axis of the R-X plane, is proposed for this

purpose.



127

The protection shall consist of two stages. The first stage with a lower range

shall be arranged to give alarm and annunication. The second stage with a

higher range shall carry out the tripping functions as shown in the Drawing --.

Generator rotor earth-fault protection (64F)

Direct current injection type of protection is proposed for this purpose. The

relay will be suitable for the field system voltage and be capable of detecting

deterioration of insulation level below about 0.2 Mega-ohms. 110 Alternating

current potential transformer auxiliary supply will be available but the relay

will have its own internal rectifiers etc. to drive the D.C. injection supply.

Failure of A.C. auxiliary supply will not totally incapacitate the protection.

The tripping of the relay is set to open the excitation breaker and bring the unit

to speed no load.

Over current relay (51 EX)

This over current instantaneous relay in the excitation circuit before the

excitation transformer will cater to rectifier transformer faults and other

excitation system faults. This relay is set to trip excitation circuit breaker and

bring the unit to speed no load.

Over excitation relay (OER) in the DC circuit and excitation relay (31) in the

field flashing circuit are other relays proposed in the excitation system.


Over Current Protection (51)

Suitable relays are proposed to be provided for unit auxiliary transformers

over load protections. The relay will operate from the three current

transformers on the Low Voltage side of the transformer and will be arranged

to trip the Low Voltage breaker as shown in the Drawing E-230-3.

An instantaneous time over current relay is proposed from the CT’s on the 11

kV side of the auxiliary transformer. This relay at a higher setting will cater to

transformer faults and the tripping of the relay is set to bring the unit to speed

no load as shown in Drawing E-230-5.

Phase sequence relay (47)

This relay on the station service system trips the LV circuit breaker so as to

prevent operation of the three phase motors in the reverse direction (Refer

Drg. -----).



128

Under voltage relay (27)

These relays have been provided to trip the LV circuit breaker (Refer Drg. ----

---).

5.4.5.4 Step up 11/---- kV Transformer Protection

Generator Transformer Differential Protection (87 GT)

A sensitive percentage biased differential relay is proposed to be provided for

each step up transformer protection with proper operating and bias setting. It

shall have harmonic restraint feature to prevent its mal-operation due to

magnetising in-rush surges encountered in normal power system operation.

Provision shall also be made for alarm/indication in case of current

transformer secondary circuits faults.

The C.T.’s on 11 kV side are proposed be located in the Generator neutral side

and on ----- kV side in the switchyard. The auxiliary/interposing current

transformers as required for the protection shall also be provided.

The relay is set to operate lockout relay for shutdown as shown in Drawing

No.-----.

Standby earth fault protection (64T)

For this protection Inverse Definite Minimum Time Lag type relay having

suitable setting range and operating time is proposed. The relay shall be

energized by zero sequence current supplied to it through current transformer

in the power transformer neutral. This relay is proposed to trip the unit circuit

breaker and bring the unit to speed no load. The relay will be co-ordinated

with line earth fault protection.

Bucholz gas pressure relay for first stage alarm and second stage trip.

Transformer oil level and temperature

Winding temperature

5.4.5.5 ----- kV – Bus Bar Protection

Bus zone Differential Protection (87 B1, and 87 B2)

A high speed, high impedance type bus-bar differential protections proposed to be

provided for each ---- kV bus zone. The scheme shall have separate and independent

check and supervision features incorporated in it.

Necessary separate C.T. cores shall be provided at the incoming and outgoing



129

circuits for check features. The main zonal relay and check relay scheme will have

their contacts connected in series in the trip circuit.

The protection will be capable of detecting all type of faults on the bus-bar. The

sensitivity of protection shall be such that it does not operate for faults on the C.T.

secondary wiring of the most heavily loaded circuit. C.T.’s on one side of the bus

coupler/section breaker are proposed and inter-locked overcurrent relay will be

provided.

The supervision relay will be capable of detecting open: Cross or broken C.T.

secondaries and pilots by employing sensitive alarm relay, which shall be connected

across the bus wires of each protected zone. It shall be capable of taking the

protection of the effected zone out of service by shorting the appropriate bus-wires.

`No volt’ relays to indicate failure of D.C. alarm and trip supply to the bus-bar

protection scheme is also proposed to be provided.

High speed tripping relays shall be provided to trip the connected circuit breakers

connected to the faulty bus bar.

5.4.5.6 --- kV Line Protection

Protective relay design for the --- kV line is important because of high fault power

from 66 kV grid sub-stations. Main features of fast acting protection system are

tentatively proposed as follows:

i) Main- Phase comparison static carrier relay (185)

ii) Backup- Directional overcurrent and ground fault (51 D)

iii) Local backup- Backup protection (FPR)

iv) Separate current transformers for two main protections.

v) One potential device per phase has each line with separate secondary winding

(independently fused) for primary and back up relay.

vi) Separately fuse D.C. tripping with separate auxiliary tripping relay.

vii) Provision of local back up protection for failure of Main and back up relay and

on breaker failure. Following Relays are provided.

5.4.5.7 Under voltage relay (27)

Under voltage relay shall be provided on the line and the bus to indicate live line

conditions. Relays with separate flush/semi-flush drawout cases and having individual

in-built testing facilities shall be preferred. But modular drawout construction and

equivalent facilities would also be accepted. The panels shall be complete and all

necessary name plates, device identification, terminals blocks, fuses etc. shall be

provided.



130

The protection requirement with respect to characteristics operating principle, tripping

schedule and type of relays shall be discussed during detailed engineering stage, and

Bidder shall provide the same to the satisfaction of the Owner.

5.4.6 Metering

Meters as shown in Schematic drawing (to be enclosed by Purchaser) shall be

provided on unit control boards. These are summarised below:

5.4.6.1 Generator (Unit Control Board)

vii. 3 ammeters (each phase)

viii. Power factor and kW meter

ix. KVAR

x. Voltmeter with voltmeter switch

xi. KWH meter

5.4.6.2 Auxiliary Transformer

iii. kWH meter

iv. Ammeters (3 No.)

5.4.6.3 Bus Coupler Panel

No Metering is required on this panel .

5.4.6.4 ---- kV Feeder Panel

v. Voltmeter with voltmeter switch

vi. 3 Ammeters (each phase).

vii. Recording kVAR (MVAR)

viii. K.W.

v. Power Factor metervi. kWH import / export meter.

5.4.7 Annunciation

Conventional 16 window annunciator for each generator turbine faults; 12 window each for feeder

faults and Bus Coupler is proposed for important faults. Schedule for these windows may be

proposed for approval by purchaser. All other annunciation will be on SCADA system.

5.4.8 Recorder

All recording will be done on SCADA disk.

5.4.9 CTs/VTs and General Surge Protection Equipment

5.4.9.1 All current and voltage transformers required for protection system of the unit aredetailed in generator specifications shall have adequate VA burdens, knee point



132

Generator Transformer 87GT with three Nos.

interposing CTs

.

(b)Generator Transformer side – Two core -6 Nos.

Core 1 Class 0.5 for AVR.

Core 2 Class 1 for metering.

2 11 kV CT ratio 600/5A in 11 kV cubicle – 6 Nos.

Single core PS class for Differential Protection of Generator 87G relay.

3 11 kV CT 11kV cubicle - 6 Nos.

(Ratio to be decided after capacity of Rectifier Transformer decided)

Single core 5P10 class for over current protection of Rectifier Transformer

circuit 51EX relay

.

4 11 kV CT ratio 30/5A in 11 kV cubicle – 6 Nos.

Single core 5P10 class for over current protection of Unit Aux. T/F

50/51 relay.

5.4.10 Control Panel Layout

Layout of Control panel is shown in enclosed drawings

5.4.11 Details of Control and Relay Panels

5.4.11.1 Generator transformer control and relay panels


equipment mounted on them shall be supplied for Generator Transformer control and

protection.

Control panels



133

S.

No.

Nomenclatu

re

Quantity Description

1. - - Mimic diagram of bus –bars and connections.

2. BI 1 set Semphore indicators for isolators.

3. CB 1 set Semphore indicators for circuit breakers.

4. AG 3 Nos. Dial type A.C. ammeters for measuringgenerator current in Amperes range 0-800A

5. VG 1No. Dial type A.C. voltmeter for measuring

generator voltage in kV range 0-15 kV

6. VS 1No. Voltmeter selector switch.

7. PF 1No Polyphase indicating power factor meter

range – 0.5 to 0 to +0.5

8. KW 1 No. Polyphase indicating kW meter of range 0 to

15000 kW

9. KVAR 1No. Polyphase indicating KVAR meter of range

0-6000 kVAR10. FM 1 No. Frequency meter 0-75 Hz

11. AF 1 No. Field current meter 0-200 A

12. VF 1 No. Field voltage meter 0-300 V

13. SI 1 No. Speed indicator 0-1000 rpm

14. SL 1No Gate limit indicator

15 SW 1 no. Remote/ local selector switch

16. A/M 1 No. Auto/manual selector switch

17 S1 1No. C.B. control switch with indicating lamps

including healthy trip supply indication.

18 S2 1 set Bus Isolator control switch with indicating

lamps19 S4 1No. Gate limiter control switch (Raise/lower )

20 S5 1 No. Speed level control switch (Raise/lower).

21. SS 1No. Synchronising switch with locking key

22. T 1 No. Temp. indicator with selector switch

23 86 G 1 No. High speed tripping relay

24 30 X 1No Emergency stop switch with cover

25 30 Y 1N. Stop reset push Button

26. KWH 1 No. Energy meter with test block

1 Set Annunciation block with 16 windows

complete with alarm cancellation lamps resetand lamp test push buttons



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Relay panels

S.

No.

Nomenclatu

re


1 87 G 1 Set Tripple pole generator differential protection

relay including auxiliary relay etc.

2 50/51T 1 No. Overcurrent Earth fault relay for Generator

transformer.

3 51 V 1 No. Backup protection relay ( over current voltage

restraint.

4 64 G 1No. Generator ground protection relay.

5 64T 1No. Transformer ground protection relay

6 59 1No Over voltage relay

7 25 1 No. Check synchronising relay

8 32 1 No, Reverse power relay

9 46 1No. Negative phase sequence relay10 40 1 No. Field failure relay

11 87 GT 3 Set. Generator Transformer differential protection

relay including auxiliary relay etc.

12 64 F 1No. Rotor earth fault relay

13 12 G 1No. Over speed relay (electrical)

14 27 1No. Under voltage relay

15 47 1No. Phase sequence voltage relay

16 84 1No. Generator trip relay

17 Auxiliary and locking relays

5.4 .11.2 --- kV feeders control and re lay panels


equipment mounted on each of them shall be supplied for Mukerian stage I and

Dasuya feeders control and protection.

Control panels

S.No.

Nomenclature



2. BI 1 set Semphore indicator for Bus isolators.

3. LI 1N0. Semphore indicator for line insulator

4. CB 1 set Semphore indicators for circuit breakers.

5. A 3 Nos. Dial type A.C. ammeters for measuring feeder

current in Amperes range 0-200A

6. V 1No. Dial type A.C. voltmeter for measuring

voltage in kV range 0 to------kV

7. VS 1No. Voltmeter selector switch.

8. KW 1 No. Polyphase indicating kW meter of range 0 to

---------kW



135

9. KVAR 1No. Polyphase indicating KVAR meter of range 0

to------ kVAR

10. S1 1No. C.B. control switch with indicating lamps


11. S2 1 set Bus Isolator control switch with indicating

lamps12. S3 1set Line Isolator control switch with indicating

lamps

13. SS 1No. Synchronising switch with locking key

14. 86 G 1 No. High speed tripping relay

15. KWH 1 No. Export/ Import Energy meter with test block

16. 1 Set Annunciation block with 16 windows

complete with alarm cancellation lamps reset

and lamp test push buttons

Relay panels

S.

No.

Nomenclatu

re


1. 51D 1 No. Directional overcurrent Earth fault relay

2. 27 1set Under voltage relay

3. 185 1set Phase comparison relay

4. 81H/L 1 set High / Low frequency relay

5. Auxiliary relays as per actual requirement.

Other protections relays as decided by feederprotection designer .

5.4 .11.3 Bus Coupler control and relay panel


equipment mounted there on shall be supplied for Bus Coupler control and protection.

Control panel

S.No.

Nomenclature



2. BI 2 sets Semaphore indicators for isolators.

3. CB 1 set Semaphore indicator for circuit breaker.

4. AB 3 Nos. Dial type A.C. ammeters for measuring

current in Amperes range 0-500A

5. S1 1No. C.B. control switch with indicating lamps


6. S2 A/B 2 sets Bus Isolator control switch with indicating

lamps



136

7. 86 G 1 No. High speed tripping relay

8. 1 Set Annunciation block with 16 windows

complete with alarm cancellation lamps reset

and lamp test push buttons

Relay panel

S.

No.

Nomenclatu

re


1.-- 87 B1/B2 2 Sets Triple pole Bus Bar differential protection relay

including check and auxiliary relays etc.

2. 51 I No. Interlocked overcurrent relay

3. Other Auxiliary relays as per requirement

7.4.11.4 Synchronizing Panel

Sheet steel swinging panel mounted on the side of the switchboard complete with internal

wiring connections equipped as synchronizing panel with the following equipment

mounted there on.


2 Nos. Dial type A.C. voltmeter of suitable range for measuring

voltage in kV.

2 Nos. Dial type frequency meters of suitable range.

1No. Synchro-scope.1No. Synchronizing lamps control switch (ON/OFF)

2Nos Synchronizing lamps.

1 No. Synchronization selector switch (Auto / Manual).

5.4.12 Test Blocks

Test blocks shall be provided on switchboards whore test facilities are required but

are not provided by use of drawout type meters or relays. The test blocks shall be of

the back connected semi-flush mounted switchboard type with removable covers. All

test blocks shall be provided with suitable circuit identification. The cases shall be

dust tight. Test blocks shall be rated not less than 250V. at 10 amps and shall becapable of withstanding a di-electric test of 1500 V, 50c/s for one minute. All test

blocks shall be arranged to isolate completely the instruments or relays from the

instrument transformers and other external circuits so that no other device will be

affected and provide means for testing either from an external source of energy or

from the instrument transformers by means of multiple test plugs. The test blocks and

plugs shall be arranged so that the C.T. secondary circuits cannot be open circuited in

any position , while the test plugs are being inserted removed.




137



correct per the specification.


verify the lighting is adequate and grounding connections are provided.14. Check anchor channels and cable entrances. Confirm they are in accordance with

the drawings.





• Cable numbers;



and lockout relay;




energized and the correct annunciation and/or printout occurs.


documents.




21. PLC checks:















schemes);







138





- Manual control to automatic control- Headwater level control “OFF” to “ON”












• Raceway layouts




15. Perform functional checks tests on all unit and station auxiliary equipmentcontrolled from the UCS to verify proper operation.







5.5 SUPERVISORY CONTROL AND DATA ACQUISITION (SCADA) SYSTEM


Design, manufacture, testing, commissioning of the Supervisory Control and Data

Acquisition (SCADA) system which includes all equipments required for

measurement, control, metering protection data logging data recording, annunciation

and sequence of event recorder, main computer, display unit with keyboard.

The SCADA system required should provide monitoring of parameters listed in

section 7.0 and control in grid mode and isolated mode operation of the Hydel Power



139

station centralized control room at EL 246.0 m. It should also provide remote

monitoring and control of the Power House from Mukerian stage I power house 7 km

from this power plant. through dedicated fibre optic cable and redundant power line

carrier communication (PLCC) system. This SCADA system should have following

features:

♦ Reliable safe control of the unit with very high availability

♦ Automatic startup, on-load control and shutdown of the units by the control

system

♦ Control of auxiliary equipment

♦ Remote monitoring of all plant status and alarm information

♦ Remote normal startup, on-load control and shutdown of units by operators.

SCADA system should have following controllers

♦ Unit Controller.

♦ Common Plant Controller/Supervisory Controller at Power House control

room

♦ Remote Supervisory Controller

The SCADA system where it is proposed to be set up in this specification shall be

designed for safe, reliable, efficient and easy operation of Hydro Turbine Generator

and its associated auxiliaries and transmission lines.

The SCADA system shall consist of a redundant microprocessor based computer

system, a dedicated sequence of events recording system, a health/condition

monitoring and analysis system, system cabinets, local panels, sensors, local

instruments, erection hardwares, interposing relays etc.

The SCADA to be supplied shall be of proven design; operation in at least six power

house for more than 5 years and will be subject to approval by purchaser and will

consist of following.

(i) Main microprocessor based computer system.

(j) Modem and Communication system(k) Data logger/sequence of events recorder.

(l) 19” colour graphic monitors with key boards

(m) System console

(n) Hard copy plotter/printer

(o) Complete field instruments like transmitter/transducers, sensors, interposing

relays, erection hardwares all interconnecting cables etc.

(p) Bidder shall supply all necessary software required for the SCADA system

including operating system, compiler, application software etc.

(q) The transducers required for the measurement of electrical parameters. The

output of transducers will be 4-20 mA.



140

The SCADA system shall be capable of performing the following functions in real

time.

o) Acquire data from primary sensors.

p) Process and retain data for each primary sensor.

q) Perform detailed thermal and vibration analysis.r) Report machine performance in tabular and graphical format.

s) Trending of turbine and generator efficiencies

t) Sequence of even logging.

u) Supervisory control of auxiliaries, governing system, excitation system, circuit

breakers, including synchronising.

v) Display software including system monitoring alarm processing and display of

data, fault, and status of devices.

w) Application software including state estimation, bad data detection, and on

line power flow.

x) Data logging and report generation.

y) Report alarms.z) Predict need for shut down and maintenance of equipment.

aa) Software shall be such that the monitoring system will take care of the

transient parameters during system run-up and shut down.

bb) Software shall be modular and upgradable.

cc) The SCADA software shall run in co-ordination with existing/proposed

SCADA software for gate control operation. It can received data of Gate

positions etc. from it and send generation etc. data to it.

5.5.2 Applicable Standards

1. I.E.E.E. - 1010 - 1987

2. I.S.O./I.E.C. - 12119

3. Applicable National and International standards for software & hardware

which will be listed.

All proposals should clearly indicate which of sub-sections of the above

standards is complied with, if any.

5.5.3 Response Time

Fast response time of computer system is required. Bidder will intimate following:

(d) Time duration required to update a graphical display from the instant a field

contact changes state.

(e) Time duration from the instant a control is activated at the operator station

until the command is implemented at the field device.

(f) Overall time duration to process and lag an alarm once it is received at the

computer.

Methodology by which these “times” were verified must be given.

Acceptable time shall be verified at the factory acceptance test.



141

5.5.4 Equipment Architecture and Protocol

Open architecture system shall be followed. Interface or operating standards for the

following shall be intimated and should comply with ISO/IEC 12119.

CommunicationsOperating system

User Interface

Data base

Each of these elements should be capable of being replaced by or communicate with

system elements provided by other vendors.

5.5.5 Plant Operation Philosophy

The normal, start-up, shut down and emergency operations of the hydro turbine

generator, auxiliaries and feeders shall be performed in three different ways asfollows:

(j) Redundant PLC based governor control panel for unit and plant control

(iv) Remote Control from Power House control room

(v) Manual control panel

The Control Engineer shall be able to perform the following operations from the CRT

through keyboards.

f) Call up mimic, alarm, data display.

g) Call up control display to carry out control operations for hydro turbine

generators and its associated auxiliaries and main & electrical power supply

systems controlled from CRT/key board.

h) Demand, logs, report including performance calculation reports, summaries,

trends and plots for hydro-turbine generator and its auxiliaries and main &

auxiliary electrical power supply system.

i) The control engineer shall be able to set up all pre-start check of devices from

the CRT/keyboard for unit starting such as :

7) The wicket gate control

8) The control of generator brakes9) Power supply to the governor

10) Load/frequency device selection on speed setting mode.

11) The selection of speed droop equal zero.

12) The blades at fully open position etc.

j) The control engineer shall be able to set the interlocks to start the unit from the

CRT/key board and once the start command is given following sequence shall

take place through the SCADA system.

1) Level control shall be put off.

2) The governor pump shall start.



142

3) When the oil pressure is established in the governor circuit, blades shall set at

the starting position.

4) Release generator brakes.

5) After having ensured that the bakes are released and blades are in starting

position command shall be given to open the wicket gates.

6) With opening of wicket gate unit speed shall rise.7) At 90% unit speed, generator shall be excited, wicket gate shall be stopped

and its position maintained by energizing governor relays speed adjustment,

blades/movements shall be achieved.

8) When unit frequency and phase voltage is matched to that of existing power

system, unit circuit breaker shall be closed.

9) After unit breaker is connected to the system, governor parameters shall be

set to automatic mode.

f) The control engineer shall be able to shut down the unit during normal condition in

the following sequence. .

1) Level control on governor shall put off

2) Blades shall close

3) When blades are closed, wicket gate shall be allowed to close.

4) When no output power is sensed unit breaker shall be tripped.

5) After unit breaker is open, blades shall open again.

6) When down stream gate is closed and unit speed is 30%, brakes, shall be

applied.

g) The control engineer shall also be able to trip the unit during emergency condition

with the following sequence. .

1) Unit breaker shall be tripped.

2) Wicket gate shall be closed.

3) Other sequence of operation as per the normal shut down.

5.5.6 Parameter to be monitored from SCADA

The SCADA system shall be complete with all primary sensors, cables, analyzers/

transmitters, monitors, system hardware/ software and peripherals etc. to monitor/ control

the parameters for control, protection, annunciation, event recording etc different equipments

detailed in 7.1 and including.

• Generator stator and rotor winding temperatures.

• Lube oil temperature

• Radio frequency interference

• Generator air gap monitoring.

• Status of generator coolant condition.

• Acoustic levels

• Vibrations

• Flow measurement.

• Turbine efficiency.

• Cavitation of turbine blades• Level measurement



143

• Turbine blade tip clearance

• Governor control monitoring of turbine speed.

• Generator terminal voltage, current, KW, KVAR, KVA, KWH,

Frequency, power factor, field voltage and field current.

• Annunciation for violation of permissible limits of the above

parameters.• Turbine bearing temperature.

• Guide bearing temperature.

• Guide bearing oil level.

• Guide vane bearing oil temperature.

• Generator bearing temperature.

• Generator winding temperature.

• Turbine speed.

• Generator speed.

• Governor oil pumps, oil pressure indicator and low pressure switch.

• Cooling water pumps, suction and discharge pressure switch/ gauge.

• Inlet pressure gauge at inlet of turbine.• Vacuum gauge for draft tube pressure.

• Level indicator for level in the forebay.

• Weir type flowmeter for measurement of flow.

• Annunciation

Bidder shall provide suggestions relating to measurement points and sensors. If in his

opinion, an enhancement in condition monitoring capability can be attained by use of

additional sensors these should be provided and details to be indicated in the bid.

5.5.7 Hardware Requirement

The key hardware features of the controller should be as follows:

♦ Standardized hardware technology

♦ Highly modular design

♦ Expandable

♦ Operation over a wide voltage range

♦ Intelligent I/O modules

♦ Central and distributed I/O

♦ Communication with other controllers and computers♦ Remote fault diagnostics

It should include all transient suppression, filtering and optical isolation necessary to

operate in a power plant environment. The type of controllers to be used in the

SCADA system should be selected to meet specific plant requirements described

below including availability, number of plant I/O, cycle time and type of

communications link. The modular design of the controllers should be such that they

are easily integrated into the control system requiring the minimum of engineering.

5.5.7.1 Unit Controller



144

Redundant microprocessor based/PLC based governor system control should be

interfaced with SCADA powerful enough to perform all the required functions

mentioned above. It should have capability to implement closed loop PID function for

governing. The scan time of the complete sequence for each process should be less

than 100 msec. It should have lock to prevent unauthorised modification and be

capable of detecting hardware and software failures. It may also have digital relays forover current, over-voltage and differential generator protection. It should have

following hardware features. It should have a console and keyboard to program the

controller as well as communicate with Supervisory controller. Unit controller should

support remote management and remote programming for supervisory controller.

5.5.7.1.1 Shut down Hardware

The controller should have a conventional relay logic shutdown circuit. This circuit

should include start and stop relays for controlling the turbine. The start relay

circuitry should provide for auto and manual control capability. A controller fail relay

should drop out the start relay when the auto relay is on. All shutdown hardwareshould be powered by the station battery. The stop relay should drop the start relay

whenever a contact input which is strapped for shutdown on a digital input module is

closed.

5.5.7.1.2 Digital Status And Alarm Inputs

The controller should be capable of connecting to at least 60 contact type inputs

representing digital status and alarms. All contact inputs should be sensed through

optical couplers with an isolation voltage of at least 1500 Volts. The controller

should accept station battery voltage level inputs. Controller input modules should be

strappable for 24, 48 or 110 Volt station batteries. Controller digital input modules

should also have straps to allow any contact input to cause a hardware shutdown

directly to the stop relay.

5.5.7.1.3 DC Analog Inputs

The controller should accept 0-1ma, 0-5V, 4-20ma or 1-5V DC analog signals. The

controller should be able to measure DC analog signals with as much as 5 voltscommon mode signal with differential inputs. The controller should provide ground

straps that can be inserted on the negative lead of any input signal that should be

grounded at the controller. The controller should also provide selective terminating

resistors for 1ma and 20ma signals. The DC analog signals should be converted to

digital signals using at minimum 12 bit analog to digital converter in the controller

with all conversion errors considered the controller should maintain an accuracy of

0.1% or better of full scale and a resolution of 1 part or less in 2000. All DC analog

inputs should be protected from transient spikes and voltages with circuitry that meets

the IEEE surge withstand test.



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5.5.7.1.4 AC current inputs

The controller should connect directly to current transformers. The controller should

accurately measure all current inputs from 0-6.25 amps. It should withstand 10 amps

continuously and 50 amps for 1 second. The controller should be able to measuremagnitude of the current with a true RMS to DC converter and its phase shift with

respect voltage. The current measuring accuracy should be to .1% and the phase shift

accuracy should be to .1 degree. The controller should induce a burden of less than

.5VA on each current transformer it connects to.

5.5.7.1.5 AC voltage inputs

The controller should connect directly to the potential transformers. The controller

should accurately measure voltage inputs from 80 to 150 VAC. It should withstandup to 200 VAC continuously. The controller should be able to measure the magnitude

of the voltage with a true RMS to DC converter and measure the phase shift of the

voltage with respect to current. The voltage measuring accuracy should be to .1% and

the phase shift accuracy should be to .1 degree. The controller should induce a

burden of less than 1 VA in each potential transformer that it connects to.

5.5.7.1.6 Control outputs

The controller should provide control relays to operate the circuit breaker, voltageregulator, and other equipment. The contacts should be DPDT rated 125 VDC at

0.5 A. Two contacts should be available from the DPDT relay and either should be

strappable as normally closed or normally open. An optional high-powered relay

should be available that provides one normally open contact rate 150 VDC at 10A.

Each relay should have an LED indicator mounted on a manual control panel to

indicate the status of the relay, on or off. Next to the indicating LED should be a

switch to operate the relay manually. Each switch/LED should be clearly marked as

to its function.

5.5.7.1.7 RTD inputs

The controller should have provisions to connect directly to RTDs. RTD readings

should be corrected for nonlinearly and readings should be accurate to + 0.25oC. The

temperature range should be 0-160oC. The controller must have a 10, 100 and 120

ohms 8 input RTD module. The correct linearizing curve should be selected by

configuring. The controller should be capable of reading temperatures from eight

RTDs. If eight RTDs are not required, any of the RTD inputs should be able to be

used as a 4-20 mA analog input. Each of the eight inputs should be assigned three

alarm set points; two high alarm set points and one low alarm set point.



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5.5.7.1.8 Analog outputs

The controller should output 4-20ma signals for calculated signals such as KW,

KVARS, power factor, frequency, voltage, and current. The signals should be

isolated outputs with 1000 common mode voltage capability. The accuracy of theseoutputs should be better than .25%.

5.5.7.1.9 Alarm outputs (option)

The controller should be capable of outputting contacts for alarms that it generates

internally. The contact rating for these alarms should be 1 Amps. at 120 VDC.

All digital inputs should be capable of meeting the surge withstand capability in

accordance with ANSI/IEEE C37.90.

5.5.7.1.10 Electrical transducers

The controller should connect directly to current transformers (CTs) and potential

transformers (PTs). The controller should be capable of deriving the generator voltage

(line to line and line to neutral), generator amps, generator WATTS, generator

VARS, generator Power factor, generator kVA, generator frequency and bus

frequency from the CTs and PTs: The controller should be configurable for open

delta (line to line) or star (line to neutral) connected CTs and PTs.

5.5.8 Supervisory Controller

Standard Desktop Redundant Computer/Mini computer should be used as Supervisory

Controller and should at minimum have following configuration:

Intel Pentium IV Processor 500 MHz (or more recent) / Desktop Mini computer with

support for running windows 2000.

512 KB second level cache

128 MB SDRAM

1.44 MB FDD

40 GB Ultra ATA HDD

40X CD-ROM driveAGP integrated graphic controller with 4 MB VRAM

17" Digital Colour Monitor

Keyboard, Mouse

5.5.9 Speed Sensor

A speed sensor to be mounted on generator unit shaft giving output as 4 to 20 mA/0-5

V DC is to be provided.

5.5.10 Wicket gate position transducer



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It should comprise of LVDT mounted on hydraulic cylinder for actuating wicket gate.

It should convert linear movement of cylinder into 4-20 mA signal. 4 mA should

correspond to 0% and 20 mA to 100% stroke of the servomotor.

5.5.11 Upstream water level transducer

Two level sensors, one float operated and other non-floated should be provided for level

controlled operation of the machine. The level controller should be redundant to each other. One

level transducer may consist of a diaphragm type sensor and internal signal conditioning system

and should be able to provide standard output such as 4 to 20 mA/0-5 V DC.

5.5.12 Speed switches

Speed switches should be provided for application of brake, overspeed tripping and

creep at 30%, 112% and 5% of the rated speed respectively.

5.5.13 Programming & Training Console

The Console should permit software development and operator training while providing

backup hardware for use where the manual operator interface is out of service.

Interlocking should be provided to permit only one console to be in control at a time.

5.5.14 Printers

Printer/Hard copy units must be provided with supervisory and unit controllers.

5.5.15 Recorders

The plant control system should include video recording system of selected parameters

i.e. Generator temperature etc.

5.6 Communication Link

i) Scope

Design, supply, delivery, Site, erection, communication and training of personnel for

communication links between the power house and Mukerian Stage I for off-site

control and communication and between power house and dasuya grid substation(interlinking points) for voice communication.



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design will be subject to approval by purchaser and will confirm to latest relevant

standard.

Local area network (LAN)

Local area network if proposed inside the Power House for distributed control otherwise

shall also connected by Fiber optic cable.

5.6.2 PLCC System

Two sets of PLCC system, line matching units and protective device shall also to be

supplied, installed and commissioned for communication and control between Power

House (emergency link) and Grid Substation for voice communication. Coupling

voltage transformer and Wave trap have been covered in switchyard equipment.

The equipment to be supplied should have got the facility of transmission of speech

and data simultaneously. Data transmission speed should be 9600 bps. To design the

PLCC system following line parameters are to be taken for a single circuit ---- kV

line.

a) Conductor - ACSR with a cross sectional area as ----mm2

b) Line impedances

i) L = -------- ohm/km per phase

ii) Inductive Reactive = -------- ohm/km per phase

iii) A.C. Resistance = --------- ohm/km at 20o

C

c) Transmission Voltage ---- kVd) Range of transmission ---- km

e) Distance between switchyard ---- meters

and control room

f) Input voltage to the system 48 V DC

Above parameters are to be worked-out taking configuration of --- kV line as right

angled with Base = ---- m and perpendicular as ---- m. These parameters may please

also be verified at Tenderers end also.

PLCC is to be interfaced with supervisory controller with serial/parallel interfaces.

Interconnection of outdoor equipment with PLCC should be done via shielded coaxialcable.



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5.7 Factory Tests for Unit Control Switchboards



correct per the specification.13. Review the interior of the UCS in the same manner as the elevations. In addition,



the drawings.





• Cable numbers;



and lockout relay;




energized and the correct annunciation and/or printout occurs.


documents.

19. Check all annunciation points.20. Check factory calibration of all devices possible, including electronic speed


21. PLC checks:







• Review the PLC ladder diagram viewed on the video display terminalversus the final approved PLC software coding documentation; and







schemes);• Auto start/stop sequence;



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5.8 Field Tests for Unit Control Switchboards






• Raceway layouts


12. Calibrate all remaining instrumentation devices.13. “Bench test” all protective relays to ensure proper settings.


controlled from the UCS to verify proper operation.







5.9 Additional Factory and Field Tests for Distributed Control Systems

7. Point-by-point database check.

8. Database linkage to graphical displays.

9. Response times during normal loading and high activity loading scenarios for:

• Graphical display updates;

• Control sequence implementation;

• Alarm processing and logging; and

• Sequence of events recording

10. Communications connectivity/protocols.

11. Man-machine interface (MMI) user capabilities.12. Application software functionality.



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5.10 Data/ Document to be furnished by the Bidder

Bidder shall furnish the following data/documents with the Bid

♦ All technical parameters such as baud rate, frequency, memory capacity

input/output capacity of modules expansion capacity of the SCADA system,

etc.

♦ Input/ Output list.

♦ List of parameters to be monitored from CRT/key board and the details of the

same.

♦ Redundancy provided for any of the equipment.

♦ List of application software.

♦ Bill of material

♦

Price schedule as per the enclosed schedule.♦ Type of Cables

♦ List of essential spares

♦ Experience list.

♦ Manual/ catalogues of each equipment supplied by him.

♦ Plant operation philosophy.

3_12 specification for monitoring control and protection of shp stations

Documents