generator protection steag

STEAG Energy Services (India) Pvt. Ltd.

Corporate Office: A – 29, Sector – 16, Noida – 201 301, India http://www.steag.in

Site Office: C/o GSEG, Opp: L&T, Hazira-Surat,Gujarat

Generator

What is Generator ?

Generators or Alternators are used to convert mechanical power derivedfrom steam gas or hydraulic turbine to AC electric powerfrom steam, gas, or hydraulic-turbine to AC electric power .

Generators are the primary source of electrical energy we consumep y gytoday.

Large AC power networks rely almost exclusively on generatorsLarge AC power networks rely almost exclusively on generators.

Generator Parts details

Stator Core Cooler


Stator Core CoolerInsertCover

End Shield

Wd O h

Rotor

Wdg Overhang

Oil Catcher

Rotor

Bearing

Shaft Seal

Stator Terminal Bushing


Generator Bearings

Generator DE & NDE b i ith

Generator bearing assembled forNDE bearings with

installed thermocouples

assembled for dimensional checks

Bearings in clean conditions

Need for Generator Protection Relay ?

Protection Relays are the Brain of the Electrical System

Need for Generator Protection Relay

A relay is automatic device which senses an abnormal condition ofGenerator circuit and closes its contacts.

Objective is to trip only the absolutely essential so that

Protection Relay make the circuit breaker tripped for disconnectingthe faulty portion of the electrical circuit from rest of the healthy circuit.

Objective is to trip only the absolutely essential so that

Damage is Minimum.

Over speeding of the Turbine due to Sudden load Throw off is avoided.

Impact of Tripping of large set on the grid is Minimum’

Auxiliary if possible are kept energies and time to restart the unit is Minimum

Generator Monitoring system

Generator monitoring system

Bearing Vibration Shaft VibrationBearing Vibration Shaft Vibration Winding Vibration Core Vibration

M h i lMechanical

Generator MonitoringGenerator Monitoring System (GEMS)Condition Electrical

•Hydrogen Purity•Hydrogen Humidity

•MW, MVAr, V, A, PfE it ti V A•Hydrogen Humidity

•Air Humidity•Water Conductivity•Gas Condition •Stator Winding Temp.

•Stator Core Temp.•Water Temp.

•Excitation V, A•AVR Indication•DIODE Monitoring•Shaft Voltage•RE, PD•Line Faultsp

•Hydrogen Pressure•Water Flow•Make Up Hydrogen Flow

•Line Faults

Generator Protection Function Group

Generator Protection Function Group

G t P t ti M i G t P t ti B kGenerator Protection Main1.Generator Differential Protection2.Stator Earth Fault Protection 100 %3 S E h F l P i 95 %

Generator Protection Backup12. Back up impedance protection13.Dead Machine Protection1 O3.Stator Earth Fault Protection 95 %

4.Rotor Earth Fault Protection 5.Loss of Excitation Protection

14.Over voltage Protection15. Under Voltage Protection 16.Under Frequency Protection

6. Over excitation Protection7. Reverse power Protection8. Negative phase sequence protn

17.Over Frequency Protection

9. Pole Slip Protection10. Generator Over load Protection11. Generator Inter turn Fault Protn

Generator Protection – ANSI CODE

GENERATOR PROTECTION ANSI CODESr. No. Protection ANSI CodeSr. No. Protection ANSI Code

1 Generator Differential 87G2 Back up impedance Stg-1 21G13 B k i d St 2 21G23 Back up impedance Stg-2 21G24 Loss excitation with under voltage (UV) 40G15 Loss of excitation without under voltage (UV) 40G26 Generator over voltage Stg-1 59G17 Generator over voltage Stg-2 59G28 Reverse Power with Turbine Trip 32G18 Reverse Power with Turbine Trip 32G19 Reverse Power without Turbine Trip 32G2

10 Generator Low Forward power 37G11 Generator Negative Phase Sequence Stg-1 46G112 Generator Negative Phase Sequence Stg-2 46G2

Generator Protection – ANSI CODE

Sr. No. Protection ANSI Code13 Rotor Earth Fault relay 64R14 Rotor over load 49R15 Generator overload 49S16 Generator Over Freq Stg-1 81G116 Generator Over Freq Stg 1 81G117 Generator Over Freq Stg-2 81G218 Generator under Freq Stg-1 81G319 G t d F St 2 81G419 Generator under Freq Stg-2 81G420 Generator Over flux 99G21 Generator CB LBB 50LBB22 Pole slip 98G23 Stator Earth Fault 95% 64G224 Stator Earth Fault 100% 64G124 Stator Earth Fault 100% 64G125 Inter turn Protection With 64G2 95G26 Dead machine Protection 50GDM

Generator Protection Function

Allocation of Generator Protection Function

Generator Protection Function -87G

Diff ti l t ti i li bl th d f t ti t

Generator Differential Protection (87G)

Differential protection is a very reliable method of protecting generators.

In a differential protection scheme, currents on both sides of theGenerator are compared.p

Under normal conditions, or for a fault outside of the protected zone,current I1 is equal to current I2 .

Ser

Therefore the currents in the current transformers secondary are alsoequal, i.e. i1 = i2 and no current flows through the current relay.

If a fault develops inside of the protected zone, currents I1 and I2 are nolonger equal, therefore i1 and i2 are not equal and there is a currentflowing through the current relay.

Generator Protection Function-87G

Generator Differential Protection (87G)

Generator Protection Function -64G1

STATOR 100 % Earth Fault Protection (64G1)

It is common practice to ground generator neutral through a resistor whichlimits maximum ground fault current to 5-10 A.

Ground fault protection function for detecting ground faults close to the star-p g gpoint of a generator.

The scheme is based on the principle of displacing the potential of thegenerator star-point by injecting a coded low-frequency signal.

achieves detection of ground faults over 100 % of the winding. Compensation isprovided for the influence of a second high-resistance grounded star-point inthe zone of protection.

The injection signal is generated by the injection unit REX 010 and fed into thestator circuit by the injection transformer block REX 011.

The principle is based on the well-known offset method using injection of a lowThe principle is based on the well known offset method, using injection of a lowfrequency signal.


STATOR 100 % Earth Fault Protection (64G1)

Parameters SettingsParameters Settings

RFs Alarm value 5kΩ

Alarm Delay 2s

RFs Trip value 0.5kΩ

Trip delay 1s


STATOR 95% Earth Fault Protection (64G2)

The 95 % scheme uses the generator voltage and detects a ground fault on thebasis of the displacement of the star-point voltage it causes.

Protection of 95 % Stator winding length against earth faults. The delay has tosafeguard against any malfunction under transient conditions and duringexternal earth faults.

This protection in conjunction with the voltage function 'Voltage', which covers95 % of the winding.

Neutral voltage relay with harmonic restraint and time delay is used.

Normally set to operate at 5% of maximum neutral voltage with delay of 0.30secsec.


STATOR 95% Earth Fault Protection (64G2)

Generator Protection Function -64R

Rotor Earth Fault Protection (64R)

f f fThe field circuit of the generator is normally isolated from the earth.

With a single earth fault in the rotor circuit, it is possible to have continuousoperation without generator damages.

There is however a risk of a second rotor earth fault .In such a case, there willbe large current and risk of severe damages .

The requirement of fast fault clearance is moderate.

Rotor earth fault relay with AC Injection Unit function

Gives alarm for weakly developed faults and tripping for fully developed fault.

Insensitive to harmonics in the filed voltage and permits capacitance between fi ld i it d d f t 5 Ffield circuit and ground of up to 5µF.

Generator Protection Function -64R

Rotor Earth Fault Protection (64R)

Generator Protection Function - 40G

Loss of Excitation Protection (40G)

There are limits for the under-excitation of a synchronous machine .

The machine may lose the synchronism and start to operate like an inductionmachine.

The under-excitation increase the generation of heat in the end region of thesynchronous machine. The local heating may damage the insulation of the statorwinding and even the iron core.

To prevent damages to the generator it should be tripped at under-excitation.Principle and operation

fThe Loss of excitation protection in Relay measures the apparent impedance seenout from the generator.

The measurement loop of apparent impedance can be chosen as the positivel f h h h h lsequence loop or any one of the three phase-to-phase loops.

Generator Protection Function - 40G

Loss of Excitation Protection (40G)

Generator Protection Function – 99G

Over Excitation Protection (99G)

As long as generator Transformer unit is connected to the network, risk of overexcitation is relatively small. However, when disconnected, there is risk of overexcitation mainly during start-up and shutdown.

Over excitation results in excessive heating of core lamination and severe heatingof unlaminated metallic parts.

Risk of the over excitation in large when frequency is below rated value and overRisk of the over excitation in large when frequency is below rated value and overvoltage relay cannot be used here and therefore, a V/Hz relay is the right one .

Over excitation protects generator magnetic core against of overheating .

Specially critical during start up and shutdown.


Over Excitation Protection (99G)


Reverse Power Protection (32G)

The task of a generator in a power plant is to convert mechanical energy availableas a torque on a rotating to electric energy.

When generator works as motor small active current is combined with largereactive current as currents are balance ,single pole relay is sufficient .

For large turbo units ,reverse power is substantially less than 1 %.Hence ,lowforward power relay can be used.

Used for the protection to prevent damage to the prime mover.

If driving torque becomes less than total losses, generator starts drawing activepower from network .

In Steam turbine, reduction of steam flow reduces cooling effect and blades areover heated.


Reverse Power Protection (32G)


Negative Phase Sequence Protection (46G)

Negative phase sequence currents produce a reverse sequence rotating field in themachine .

This induces double frequency eddy currents in the rotor leading to overheating,primarily on surface of cylindrical rotors and damper winding of salient polemachines.

Causes of Negative phase sequence in Generator Unbalanced load Unbalanced system faults Open circuit One pole of CB or Isolator not closed.

Unbalance loading gives rise to double frequency eddy currents induced in rotorwhich may cause excessive overheating .


Negative Phase Sequence Protection (46G)


Pole Slip Protection (98G)

L t tibl t l f h i d t l i tiLarge generator are more susceptible to loss of synchronism due to lower inertia, higher reactance and also if connected by relatively weak ties. if allowed to persist result in instability and widespread system disturbance.

P l Sli iPole Slipping

In this state, plant is still in excited state and large fluctuations in stator voltage current and power output of the machine occur.

Protection Function operation and Measurement

If Generator is faster than the power system, the rotor movement in the impedance and oltage diagram is from right to left and generating is signaledand voltage diagram is from right to left and generating is signaled.If the generator is slower than the power system, the rotor movement is from left to right and motoring is signaled.The movement in the impedance plain can be seen in figure, the transient behavior is described by the transient e m f’s E d E d b X’ X d th t i t tis described by the transient e.m.f’s EA and EB,and by X’d. XT and the transient system impedance ZS.


Pole Slip Protection (98G)

Generator Protection Function – 49S

If the temperature of the generator reaches too high values the equipment might be

Overload protection (49S)

If the temperature of the generator reaches too high values the equipment might bedamaged.

As a consequence of this the risk of internal phase to phase or phase to earthfaults will increasefaults will increase.

The thermal overload protection estimates the internal heat content of thegenerator continuously.

The Protection measure maximum phase current (true RMS Measurement).

In this REG 670 Protection Relay Two warning levels are available .This enablesactions in the power system to be done before dangerous temperature are reachedactions in the power system to be done before dangerous temperature are reached.If the temperature continues to increase to the trip value ,the protection initiatestrip of the protected generator

Generator Protection Function – 49S

Overload protection (49S)

Generator Protection Function – 95G/64W

Generator Inter turn Fault (95G or 64W)

Differential protection for stator does not provide protection against theinter-turn faults on the same phase winding of the stator.

The reason is that the current produced by the turn to turn fault flows inthe local circuit between the turns involved and thus it does not createany difference between the current.

1. The protection criterion (for aninterturn fault)

2. which the REU 610 evaluates is theneutral voltage of the phase-to-neutralvoltages. The necessary sensitivity isachieved using a special input anddigital filter algorithms.

Generator Protection Function – 95G/64W

Generator Inter turn Fault (95G or 64W)


Backup Impedance Protection (21G)Backup impedance protection for internal short circuit in the generator or the unitp p p gtransformer .

Backup or main protection for fault at the bus bar where the plant is connected tothe power system .p y

Backup impedance protection for line-faults at lines out from the power plant .

The numerical mho line distance protection is a three zone full scheme protectionp pfor back-up detection of short circuit and earth faults.

The three zones have fully independent measuring and setting which gives highflexibility for all types of lines.y yp

The modern technical solution offers fast operating time down to ¾ cycles.


Backup Impedance Protection (21G)

Generator Protection Function – 50GDM

Dead Machine Protection (50GDM)

If a dead machine is accidentally energized (energized while on turningIf a dead machine is accidentally energized (energized while on turninggear), it will start and behave as an induction motor.

During the period when the machine is accelerating, very high currentsare induced in the rotor and the machine may be damaged very quickly.are induced in the rotor and the machine may be damaged very quickly.relays do detect the event, their time delays may be too great to avoiddamage to the generator.

Because of these problems, dedicated dead machine protection is oftenp , padvisable.

Protection relay must have a very short time delay in order to adequatelyprotect the useful for system fault backup protection.p y p p

Protection against dead-machine energization can also be provided with adirectional over current relay connected at the machine terminals and setto operate for currents flowing into the machine.

Generator Protection Function – 50GDM

Dead Machine Protection (50GDM)


Over voltage Protection (59G)

Generator overvoltage may occur during a load rejection or excitationGenerator overvoltage may occur during a load rejection or excitationcontrol failure.

upon load rejection the generator may speed up and the voltage canreach high levels without necessarily exceeding the generator’s V/Hzreach high levels without necessarily exceeding the generator s V/Hzlimit.

The overvoltage relay (59) is used to protect the generator from thisconditioncondition.

The over voltage protection is provided by two over voltage Functionhave two Step – one is the instantaneous relays which is set to pickup at 130 to 150% of the rated voltage. another Step is IDMT which isset to pick up at 110% of rated voltage.

Over voltage may occur due to the defective voltage regulator andOver voltage may occur due to the defective voltage regulator andalso due to manual control errors.


Over voltage Protection (59G)


Under voltage Protection (27G)

If more than one generators supply the load and due to some reason oneIf more than one generators supply the load and due to some reason one generator is suddenly trip , then another generators try to supply the load. Each of these generators will experience a sudden increase in current and thus decreases the terminal voltage.

Automatic voltage regulator connected to the system try to restore the voltage.

And under voltage relay type-27 is also used for the under voltageAnd under voltage relay type 27 is also used for the under voltage protection.

This drop of under voltage not critical for the generator and transformer block .block .

Critical for the auxiliary equipment at plant (especially for turbo units).

This Protection function should be block when generator is not loaded .


Under frequency Protection (81G3)Under Frequency occurs as a result of lock of generation in the Network .

Overloading of a generator, perhaps due to loss of system generation and insufficient load shedding, can lead to prolonged operation of the generator at reduced frequenciesreduced frequencies.

This can cause particular problems for gas or steam turbine generators, which are susceptible to damage from operation outside of their normal frequency band.

While load-shedding is the primary protection against generator overloading, under frequency relays (device 81U) should be used to provide additionalunder frequency relays (device 81U) should be used to provide additional protection.

The under frequency (TUF) function is used to detect low power system f th f ti ith h d fi it ti d l ltfrequency ,the function can either have a definite time delay or a voltage magnitude depend the time delay .

Generator Protection Function – 81G3

Under frequency Protection (81G3)


Over frequency Protection (81G1)

Over frequency will occur at sudden load drops or shunt faults in the powerOver frequency will occur at sudden load drops or shunt faults in the powernetwork .

In some case close to generating part governor problem can also cause overffrequency .

The protection function is provided with an undervoltage blocking ,the operationmay be based on single phase, phase-to-phase or positive sequence voltageay be based o s g e p ase, p ase to p ase o pos t e seque ce o tagemeasurment .

The Over frequency (TOF) function is used to detect high power systemfrequency the function has a settable definite time delay if the frequencyfrequency ,the function has a settable definite time delay.if the frequencyremains above the set value for a time period corresponding to the chosen timedelay .


Over frequency Protection (81G1)

Generator Class of Tripping

CLASS-A TRIPPING

This is adopted for those Electrical Faults of Generator and Generator Transformer and unit Auxiliary Transformer for which tripping can not be delayed.y

This leads to simultaneous tripping of

Generator Transformer HV Side CB

Field Circuit Breaker

LV side Incomer Breaker of UAT’s

Auto Changeover from unit to Station for unit Auxiliaries andAuto Changeover from unit to Station for unit Auxiliaries and tripping of turbine.


Thi i d t d f ll t bi f lt (M h i l) d f El t i l

CLASS-B TRIPPING

This is adopted for all turbine faults (Mechanical) and for some Electricalfaults of Generator ,Generator Transformer and unit auxiliaryTransformer for which it is safe to trip the turbine.

Subsequently the Generator is tripped through low forward powerinterlock.

Ensure that unit does not over speed due to trapped steam in the turbineduring the shutdown and also the loss of power to the grid from theGenerator is not sudden.


CLASS-C TRIPPING

This is adopted for all faults beyond the Generator system which can becleared by tripping of Generator transformer HV Side CB alone.

In this case the TG Set runs with HP-LP bypass system in operation andGenerator continues to feed the unit auxiliary load through unit auxiliaryGenerator continues to feed the unit auxiliary load through unit auxiliaryTransformers.

Classification of Tripping

Typical Classification of Tripping PROTECTIVE RELAY TRIPPING MODE REMARKS

Generator Differential Relay Class ‘A’Generator Transformer Differential Relay

Class ‘A’

Unit Overall Differential Relay Class ‘A’Generator Stator E/F Relay (100%) Class ‘A’Generator Stator E/F Relay (95%) Class ‘A’Generator Transformer Over fluxing Relay

Class ‘B I stage alarm

Generator Under frequency Relay Class ‘C’ After some time (say 3omins) II stage

I stage alarm(say 3omins) II stage

Generator Rotor Earth Fault Relay Class ‘B’ II stage I stage alarmGenerator Pole slipping Relay Class ‘C’Generator Field Failure Relay Class ‘B’ Without Under voltageGenerator Field Failure Relay Class B Without Under voltageGenerator Low Forward Power Relay

For interlock in Class ‘B” tripping

Classification of Tripping

Typical Classification of Tripping PROTECTIVE RELAY TRIPPING MODE REMARKS

Generator Reverse Power Relay Class ‘A’Generator Distance Backup Impedance Relay Class ‘C’Generator Voltage Restrained Relay Class ‘A’Generator Transformer H.V. side Backup O/C relay Class ‘C’

Generator Transformer H.V. side Backup E/F relay Class ‘B’Unit Auxiliary Transformer Differential Relay Class ‘A’

Generator Negative Sequence Current Relay Class ‘C’ I-stage alarmGenerator Definite time O/C Relay For alarmUnit Auxiliary Transformer H.V. side O/C Relays (Backup)

Class ‘A’

Generator Transformer Buchholz Relay Class ‘A’ Il-stage I-stage alarmGenerator Transformer Winding Temperature Device

Class ‘C’ Il-stage I-stage alarm

Generator Transformer Oil Temperature Device Class ‘C’ Il-stage I-stage alarm

Generator Protection Matrix

Generator Protection Matrix

Measurement Circuit for Generator Protection

Generator Protection Relay

Generator Protection Relay - Requirement & Classification

The Protection Relays areclassified by followingconstruction type:

The Protection Relaysshould meet followingrequirements:

ElectromagneticSolid stateMi

Reliability : ability to operate correctly. It has two component Microprocessor

NumericalNon-electric (thermal,

pressure etc )

componentDependabilitySecurity

Speed: minimum pressure, etc.,)Speed: minimum operating time to clear the fault

Cost: maximum protection at lowest possible cost


Generator Protection Relay Classification

Electromagnetic Based relay construction

Electromagnetic relays includeattracted armature, moving coil,and induction disc induction cuptype relays. Electromagnetic relayscontain an electromagnet (or apermanent magnet) and a movingpermanent magnet) and a movingpart. When the actuating quantityexceeds a certain predeterminedvalue, an operating torque isdeveloped which is applied on the

i t Thi thmoving part. This causes themoving part to travel and to finallyclose a contact to energise the trip-coil of the breaker.

Electromagnetic Type Relays

Type-CDG 12

Inverse Time Earth Fault

Type-CAG 17,37yp ,

Instantaneous Over current

Type-CDV,22,62

Voltage controlled Over current Relay

Type-CTMM/CTMFM

Motor Protection Relay

Type-CTNM 12

Negative Phase Sequence current relay



Solid state Based relay constructionco st uct o

Static relays contain electronic circuit which areStatic relays contain electronic circuit, which aretransistors, ICs, diodes another electroniccomponents. There is a comparator circuit in therelay, which compares two or more currents orvoltages and gives the output, which is applied toeither a slave relay or a thryristor circuit. The slaverelay is an electromagnetic relay in a semi- staticrelay. A relay using a thryristor circuit is a whollystatic relay. Static relay possess an advantage ofhaving low burden on CT and PT fast operationhaving low burden on CT and PT, fast operation,absence of mechanical inertia, contact time, long lifeand less maintenance. Static relays have proved tobe superior to electromagnetic relays



Microprocessor Based relayBased relay construction

NumericalNumerical Based relay construction


Generator Protection Relay – Numerical Relay Function

A numeric relay is a digital protective relay that uses a microprocessor with software basedprotection algorithms to analyze power system voltages and currents for the purpose ofdetection of faults in an electric power system.

F tiFunction:Low voltage and low current signals (i.e., at the secondary of a voltage transformer andcurrent transformer ) are brought into a low pass filter that removes frequency contentabove about 1/3 of the sampling frequency. AC signal is then sampled by the relay's analogto digital converter at anywhere from about 4 to 64 (varies by relay) samples per powersystem cycle. The sampled data is then passed through a low pass filter that numericallyremoves the frequency content that is above the fundamental frequency of interest (i.e.,nominal system frequency), and uses Fourier transform algorithms to extract thef d t l f it d d lfundamental frequency magnitude and angle.

Next the microprocessor passes the data into a set of protection algorithms, which are a setof logic equations in part designed by the protection engineer, and in part designed by therelay manufacturer, that monitor for abnormal conditions that indicate a fault. If a faultcondition is detected, output contacts operate to trip the associated circuit breaker(s).


Architecture of numerical relays

MicroprocessorMicroprocessorMemory moduleInput moduleO t t d lOutput moduleCommunication moduleApplication Softwarepp

Advantage of Numerical RelayReliabilityM ltif ti litMultifunctionalitySelf DiagnosisEvent and Disturbance RecordsCommunication Capabilities

Sampled WaveformCo u cat o Capab t esAdaptive Protection


Numerical relays Fourier transform algorithms


Architecture of numerical relays

Generator Protection Relay- REG 670

Generator Protection Relay – ABB make REG 670

The REG 670 is used for protection ,control andmonitoring of the generator and generatortransformer blocks.

The IED has a comprehensive function library,p y,covering the requirement for most generatorapplication.

The REG670 also enables valuable monitoringgpossibilities as many of the process values can betransferred to an operator HMI.

REG 670 inbuilt with 33 Protection function. A/D module with one microsecond accuracyA/D module with one microsecond accuracy in time synchronization .New GPS clock module .Transformer input module with three metering CTs, four protection CTs and five VTs .

Generator Protection Relay REG 670



Protection Relay – Function Monitoring


Relay Communication

Generator mechanical protection

Generator Mechanical Protection Alarm Limit setting Sr. NO Parameter Operating Value Alarm Value Trip Value

1 Stator slot temparature (24 RTDs) 95 100 ºC >1001 Stator slot temparature (24 RTDs) 95 - 100 ºC >100

2 Stator core Temperature

Turbine End < 95 ºc > 100 ºC

Excitor End < 95 ºC > 100 ºC

3 Cold gas temp after H2 coolers

AB (3 RTDs) 25 - 45 ºC > 50 ºC > 50 ºC

CD (3RTDs) 25 - 45 ºC > 50 ºC > 50 ºC

4 Hot gas temp before H2 coolers4 Hot gas temp before H2 coolers

AB (2 RTDs) 45 - 70 ºC > 75 ºC

CD (2RTDs)

5 Cooling water Temp before H2 coolers

A < 38 ºC > 38 ºC

B < 38 ºC > 38 ºC

6 Cooling water Temp after H2 coolers < 50 ºC > 50 ºC

7 Generator Brg.Temp TE Side (2 RTDs) < 90 ºC > 90 ºCg p ( )

8 Generator Brg.Temp EE Side (2 RTDs) < 90 ºC > 90 ºC

9 Generator Brg. Vibration TE < 84 ºC > 84 ºC

10 Generator Brg. Vibration EE < 84 micron pk-pk > 84 micron pk-pk

Generator Protection Setting

Generator Protection setting – 230 MW Generator Sr. No. Protection Setting REG 670 Pickup Setting Time Delay

1 Generator differential protection 0.2 IBASE 01 Generator differential protection 0.2 IBASE 02 Gen Backup impedance Stage-1(21G1) 0.099 ohm/ph, 80 deg 1 s3 Gen Backup impedance Stage-2 (21G2) 0.141 ohm/ph, 80 deg 1 s

4 Loss of Excitation with under voltage (40G1)Zone-1 : Z1 offset: 10, Z1 diameter: 86.37 %, UV:70% 1 S

0 sUV:70%, 1 SZone-2 : Z2 offset: 10, Z2 diameter: 86.37 %, UV:70%, 1 S

0 s

5 Loss of Excitation without under voltage (40G)2 Zone-1 : Z1 offset: 10, Z1 diameter: 86.37 %, 0 sdiameter: 86.37 %, Zone-2 : Z2 offset: 10, Z2 diameter: 86.37 %, 0 s

6 Over load protection Stage-1 (59G1) 110 IB% 3 s7 Over voltage protection Stage-2 (59G2) 115 %UB 3 s8 R P ith t bi t i (32G1) 0 5% SB 180 d 38 Reverse Power with turbine trip (32G1) 0.5% SB, 180 deg 3 s

9 Reverse Power with out turbine trip (32G2) 0.5% SB, 180 deg 3 s

10 Low forward protection (37 G) 0.5% SB, 180 deg 3 s

11 Negative Phase Sequence Stage-1 (46G1) 10% IB, 0, 120, 240 deg 2 s11 Negative Phase Sequence Stage 1 (46G1) 2 s

12 Negative Phase Sequence Stage-2 (46G2) 10% IB, 0, 120, 240 deg IEC – Extremely Inverse

Generator Protection Setting

Generator Protection setting – 230 MW Generator Sr. No. Protection Setting REG 670 Pickup Setting Time Delay

13 Rotor earth fault protection (64 R) Alarm -10KΩ 0.50 s13 Rotor earth fault protection (64 R) Alarm 10KΩ 0.50 sTrip – 1 KΩ 0.50 s

14 Rotor Overload Protection (49 R) 110% Ibase 5 s15 Generator Overload Protection (49 S) 105% Ibase 5 s

16 Over Frequency Protection (81 G1) Alarm: 51.50 Hz 10 s

17 Over Frequency Protection (81 G2) Trip: 52.50 Hz 1 s

18 Under Frequency Protection (81 G3) Alarm: 48.50 Hz 5 s19 Under Frequency Protection (81 G4) Trip: 47.40 Hz 2 s20 O fl i t ti (99 G) 110 140 % V/H 020 Over fluxing protection (99 G) 110 – 140 % V/Hz 0 s21 Generator CB LBB Protection (50 LBB) 10% Ibase 0.2 s22 Pole Slip protection (98G) ZA = 13.55 %, 105-90 deg 0 s

ZB = 16.57 %, 105-90 deg 0 sZC = 15.34 %, 105-90 deg 0 s, g

23 Stator 1 00% earth fault protection (64 G1) Alarm -1KΩ 0.50 sTrip - 1KΩ 0.50 s

24 Stator 95 % earth fault protection (64 G2) 0.05 Un 0.5 s25 INTERTURN fault protection (95 G1) >5.0 Un 0.1 s26 Dead machine Protection (50 GDM) I >= 105 %, UV <= 70% 0 s

Sonntag, 12. August 2012 67

generator protection steag

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generator protection

generator protection

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