csc-150 busbar protection ied technical application manual_v1.01

CSC-150

Busbar Protection IED

Technical Application Manual

CSC-150 Busbar Protection IED

Technical Application Manual

Compiled: Jin Rui

Checked: Hou Changsong

Standardized: Li Lianchang

Inspected: Cui Chenfan

Version： V1.01

Doc.Code：0SF.450.087(E)

Issued Date：2012.8.31

Version：V1.01

Doc. Code: 0SF.450.087(E)

Issued Date：2012.8

Copyright owner: Beijing Sifang Automation Co., Ltd

Note: the company keeps the right to perfect the instruction. If equipment does not agree with

the instruction at anywhere, please contact our company in time. We will provide you with

corresponding service.

® is registered trademark of Beijing Sifang Automation Co., Ltd.

We reserve all rights to this document, even in the event that a patent is issued and a different commercial proprietary right is registered. Improper use, in particular reproduction and dissemination to third parties, is not permitted.

This document has been carefully checked. If the user nevertheless detects any errors, he is asked to notify us as soon as possible.

The data contained in this manual is intended solely for the IED description and is not to be deemed to be a statement of guaranteed properties. In the interests of our customers, we constantly seek to ensure that our products are developed to the latest technological standards as a result it is possible that there may be some differences between the hardware/software product and this information product.

Manufacturer: Beijing Sifang Automation Co., Ltd.

Tel: +86 10 62962554, +86 10 62961515 ext. 8998 Fax: +86 10 82783625 Email: [email protected] Website: http://www.sf-auto.com

Add: No.9, Shangdi 4th Street, Haidian District, Beijing, P.R.C.100085

Preface

Purpose of this manual

This manual describes the functions, operation, installation, and placing into service of IED CSC-150. In particular, one will find:

Information on how to configure the IED scope and a description of the IED functions and setting options;

Instructions for mounting and commissioning;

Compilation of the technical specifications;

A compilation of the most significant data for experienced users in the Appendix.

Target audience

This manual mainly face to installation engineer, commissioning engineer and

operation engineer with perfessional electric and electrical knowledge, rich

experience in protection function, using protection IED, test IED, responsible

for the installation, commissioning, maintenance and taking the protection

IED in and out of normal service.

Applicability of this manual

This manual is valid for CSC-150 multifunction protection IED.

Technical support

In case of further questions concerning the CSC family, please contact

SiFang compay or your local SiFang representative.

Safety information

Strictly follow the company and international safety regulations.

Working in a high voltage environment requires serious approch to

aviod human injuries and damage to equipment

Do not touch any circuitry during operation. Potentially lethal

voltages and currents are present

Avoid to touching the circuitry when covers are removed. The IED

contains electirc circuits which can be damaged if exposed to static

electricity. Lethal high voltage circuits are also exposed when covers

are removed

Using the isolated test pins when measuring signals in open circuitry.

Potentially lethal voltages and currents are present

Never connect or disconnect wire and/or linker to or from IED during

normal operation. Dangerous voltages and currents are present.

Operation may be interrupted and IED and measuring circuitry may

be damaged

Always connect the IED to protective earth regardless of the

operating conditions. Operating the IED without proper earthing may

damage both IED and measuring circuitry and may cause injuries in

case of an accident.

Do not disconnect the secondary connection of current transformer

without short-circuiting the transformer’s secondary winding.

Operating a current transformer with the secondary winding open will

cause a high voltage that may damage the transformer and may

cause injuries to humans.

Do not remove the screw from a powered IED or from an IED

connected to power circuitry. Potentially lethal voltages and currents

are present

Using the certified conductive bags to transport PCBs (modules).

Handling modules with a conductive wrist strap connected to

protective earth and on an antistatic surface. Electrostatic discharge

may cause damage to the module due to electronic circuits are

sensitive to this phenomenon

Do not connect live wires to the IED, internal circuitry may be

damaged

When replacing modules using a conductive wrist strap connected to

protective earth. Electrostatic discharge may damage the modules

and IED circuitry

When installing and commissioning, take care to avoid electrical

shock if accessing wiring and connection IEDs

Changing the setting value group will inevitably change the IEDs

operation. Be careful and check regulations before making the

change

Contents

Chapter 1 Introduction ....................................................................................................................... 1

1 Overview ........................................................................................................................................... 2

2 Features ............................................................................................................................................ 3

3 Functions .......................................................................................................................................... 5

3.1 Protection functions ........................................................................................................ 5

3.2 Monitoring functions ........................................................................................................ 5

3.3 Station communication ................................................................................................... 5

3.4 IED software tools ........................................................................................................... 6

Chapter 2 General IED application ................................................................................................. 7

1 Display on LCD screen ................................................................................................................... 8

1.1 LCD screen display function .......................................................................................... 8

1.2 Analog display function................................................................................................... 8

1.3 Report display function ................................................................................................... 8

1.4 Menu dispaly function ..................................................................................................... 8

2 Report record ................................................................................................................................... 9

3 Disturbance recorder .................................................................................................................... 10

3.1 Introduction ..................................................................................................................... 10

3.2 Setting ............................................................................................................................. 10

4 Self-supervision function .............................................................................................................. 11

4.1 Self supervision principle ............................................................................................. 11

4.2 Self supervision report .................................................................................................. 11

5 Time synchroniation function ....................................................................................................... 12

5.1 Introduction ..................................................................................................................... 12

5.2 Synchronization principle ............................................................................................. 12

5.2.1 Synchronization from IRIG ........................................................................................... 13

5.2.2 Synchronization via PPS or PPM ............................................................................... 13

5.2.3 Synchronization via SNTP ........................................................................................... 13

6 Setting ............................................................................................................................................. 14

6.1 Introduction ..................................................................................................................... 14

6.2 Operation principle ........................................................................................................ 14

7 Authorization .................................................................................................................................. 15

7.1 Introduction ..................................................................................................................... 15

Chapter 3 Busbar differential protection ....................................................................................... 17

1 Busbar differential protection ....................................................................................................... 18

1.1 Introduction ..................................................................................................................... 18

1.2 Protection principle ........................................................................................................ 18

1.2.1 Operation principle ................................................................................................ 18

1.2.2 Automatic ratio compensation ............................................................................. 20

1.2.3 Disconnector replica ............................................................................................. 20

1.2.4 Circuit breaker status ............................................................................................ 21

1.2.5 Current transformer open circuit supervision .................................................... 21

1.2.6 Differential current saturation supervision .......................................................... 21

1.2.7 Sequence trip ......................................................................................................... 22

1.2.8 Logic diagram ......................................................................................................... 22

1.3 Input and output signals ................................................................................................ 23

1.4 Setting parameters ........................................................................................................ 23

1.4.1 Setting list ............................................................................................................... 23

1.5 Reports ............................................................................................................................ 24

1.6 Technical data ................................................................................................................ 24

Chapter 4 Circuit breaker failure protection ................................................................................. 27

1 Circuit breaker failure protection ................................................................................................. 28

1.1 Introduction ..................................................................................................................... 28


1.2.1 General description of CBF protection ............................................................... 28

1.2.2 The current criterion evaluation ........................................................................... 29

1.2.3 Logic diagram ......................................................................................................... 30


1.4 Setting parameters ........................................................................................................ 31

1.4.1 Setting list ............................................................................................................... 31

1.5 IED reports ...................................................................................................................... 39

1.6 Technical data ................................................................................................................ 40

Chapter 5 Dead zone protection .................................................................................................... 41

1 Dead zone protection .................................................................................................................... 42

1.1 Introduction ..................................................................................................................... 42


1.2.1 Function description .............................................................................................. 42

1.2.2 Logic diagram ......................................................................................................... 44


1.4 Setting parameter .......................................................................................................... 45

1.4.1 Setting list ............................................................................................................... 45

1.5 IED reports ...................................................................................................................... 47

1.6 Technical data ................................................................................................................ 47

Chapter 6 Secondary system supervision .................................................................................... 49

1 Current circuit supervision ............................................................................................................ 50

1.1 Introduction ..................................................................................................................... 50

1.2 Function principle ........................................................................................................... 50

1.2.1 Current circuit supervision for feeder .................................................................. 50

1.2.2 Current circuit supervision for busbar coupler ................................................... 50

1.2.3 Logic diagram ......................................................................................................... 50



1.4.1 Setting list ............................................................................................................... 52

1.5 IED reports ...................................................................................................................... 53

2 Fuse failure supervision VT.......................................................................................................... 54

2.1 Introduction ..................................................................................................................... 54

2.2 Function principle .......................................................................................................... 54

2.2.1 Three phases (symmetrical) VT Fail ................................................................... 54

2.2.2 Single/two phases (asymmetrical) VT Fail ........................................................ 54

2.2.3 Logic diagram ........................................................................................................ 54

2.3 Input and output signals ............................................................................................... 55


2.4.1 Setting list ............................................................................................................... 56

2.5 IED reports ..................................................................................................................... 56

2.6 Technical data ................................................................................................................ 56

3 Auxiliary contacts of circuit breaker and disconnector supervision ....................................... 57

Chapter 7 Monitoring function ........................................................................................................ 59

1 Self-supervision ............................................................................................................................. 60

Chapter 8 Station communication ................................................................................................. 61

1 Overview ......................................................................................................................................... 62

1.1 Protocol ........................................................................................................................... 62

1.1.1 IEC61850-8 communication protocol ................................................................. 62

1.1.2 IEC60870-5-103 communication protocol ......................................................... 62

1.2 Communication port ...................................................................................................... 63

1.2.1 Front communication port .................................................................................... 63

1.2.2 RS485 communication ports................................................................................ 63

1.2.3 Ethernet communication ports ............................................................................. 63

1.3 Technical data ................................................................................................................ 63

1.4 Typical substation communication scheme ............................................................... 65

1.5 Typical time synchronizing scheme ............................................................................ 65

Chapter 9 Hardware ........................................................................................................................ 67

1 Introduction ..................................................................................................................................... 68

1.1 IED structure .................................................................................................................. 68

1.2 IED module arrangement ............................................................................................. 68

2 Local human-machine interface .................................................................................................. 70

2.1 Introduction ..................................................................................................................... 70

2.2 Liquid crystal display (LCD) ......................................................................................... 71

2.3 LED .................................................................................................................................. 71

2.4 Keyboard ........................................................................................................................ 71

2.5 IED menu ........................................................................................................................ 72

2.5.1 Menu construction ................................................................................................. 72

2.5.2 Operation status .................................................................................................... 74

2.5.3 Settings ................................................................................................................... 75

2.5.4 Query report ........................................................................................................... 75

2.5.5 Setup ....................................................................................................................... 75

2.5.6 Test BO ................................................................................................................... 76

2.5.7 Set Time .................................................................................................................. 76

2.5.8 Testing ..................................................................................................................... 76

2.5.9 Contrast .................................................................................................................. 77

3 Analog input module ..................................................................................................................... 78

3.1 Introduction ..................................................................................................................... 78

3.2 Terminals of analog input module ............................................................................... 78

3.3 Technical data ................................................................................................................ 80

4 Communication module ................................................................................................................ 82

4.1 Introduction ..................................................................................................................... 82

4.2 Terminals of communication module .......................................................................... 82

4.3 Substaion communication port .................................................................................... 83

4.3.1 RS232 communication ports ................................................................................ 83

4.3.2 RS485 communication ports ................................................................................ 83

4.3.3 Ethernet communication ports ............................................................................. 83

4.3.4 Time synchronization port .................................................................................... 84

4.4 Technical data ................................................................................................................ 84

5 Binary input module ....................................................................................................................... 86

5.1 Introduction ..................................................................................................................... 86

5.2 Terminals of binary input module ................................................................................ 86

5.3 Technical data ................................................................................................................ 89

6 Binary output module .................................................................................................................... 91

6.1 Introduction ..................................................................................................................... 91

6.2 Terminals of binary output module .............................................................................. 91

6.3 Technical data ................................................................................................................ 97

7 Power supply module .................................................................................................................... 98

7.1 Introduction ..................................................................................................................... 98

7.2 Terminals of power supply module ............................................................................. 98

7.3 Technical data .............................................................................................................. 100

8 Technical data .............................................................................................................................. 101

8.1 Type tests ..................................................................................................................... 101

8.2 IED design .................................................................................................................... 105

8.3 CE certificate ................................................................................................................ 105

Chapter 10 Appendix ....................................................................................................................... 107

1 General setting list ....................................................................................................................... 108

1.1 IED parameter .............................................................................................................. 108

1.2 Function setting list ...................................................................................................... 109

1.3 Binary setting list .......................................................................................................... 113

2 General report list ........................................................................................................................ 118

3 Typical connection ....................................................................................................................... 121

4 CT Requirement ......................................................................................................................... 132

4.1 Overview ...................................................................................................................... 132

4.2 Current transformer classification ........................................................................ 132

4.3 Abbreviations (according to IEC 60044-1, -6, as defined) ............................... 133

4.4 General current transformer requirements ........................................................ 134

4.4.1 Protective checking current ........................................................................... 134

4.4.2 CT class ............................................................................................................... 135

4.4.3 Accuracy class ................................................................................................... 137

4.4.4 Ratio of CT .......................................................................................................... 137

4.4.5 Rated secondary current ................................................................................. 137

4.4.6 Secondary burden ............................................................................................. 137

4.5 Rated equivalent secondary e.m.f requirements .............................................. 138

4.5.1 Busbar differential protection ........................................................................ 138

Chapter 1 Introduction

1


About this chapter

This chapter gives an overview of SIFANG Busbar Protection

IED.


2

1 Overview

The CSC-150 is selective, reliable and high speed busbar protection IED

(Intelligent Electronic Device), with powerful capabilities to cover following

applications:

For various busbar arrangements, including those listed below:

Single Busbar

Two Single Busbars connected with bus coupler

Two Separate Busbars in 1

CB arrangement

Double Busbar

Main and Transfer Busbar

Double Main and one Transfer Busbar

Main and Main/Transfer Busbar

For solidly earthed, low impedance earthed or isolated power system

Used in a wide range of voltage levels, up to 750kV

Communication with station automation system

The IED provides reliable busbar differential protection with integrated check

zone, short saturation-free time and fast tripping time as well as circuit

breaker failure protection and dead zone protection.


3

2 Features

Protection and monitoring IED with extensive functional library, user

configuration possibility and expandable hardware design to meet with

user’s special requirements

Inter-lock between two CPU modules, avoiding maloperation due to

internal severe fault of one module

Busbar differential protection (87BB)

Low-impedance centralized differential protection

Selective zone tripping

Extreme stability against exteral fault, short CT saturation-free time

Phase-segraegated measuring system

Integrated check zone

Bus couplers/disconnetor is definable in busbar scheme

A complete protection functions library, include:

Busbar differential protection (87BB)

Circuit breaker failure protection (50BF)

Dead zone protection (50SH-Z)

Voltage transformer secondary circuit supervision (97FF)

Current transformer secondary circuit supervision

Self-supervision to all modules in the IED

Complete IED information recording: tripping reports, alarm reports,

startup reports and general operation reports. Any kinds of reports can be

stored up to 2000 and be memorized in case of power disconnection

Up to three electric /optical Ethernet ports can be selected to

communicate with substation automation system by IEC61850 or

IEC60870-5-103 protocols

Up to two electric RS-485 ports can be selected to communicate with

substation automation system by IEC60870-5-103 protocol

Time synchronization via network(SNTP), pulse and IRIG-B mode

Configurable LEDs (Light Emitting Diodes) and output relays satisfied

users’ requirement

Versatile human-machine interface


4

Multifunctional software tool CSmart for setting, monitoring, fault

recording analysis, configuration, etc.


5

3 Functions

3.1 Protection functions

Description ANSI Code

IEC 61850

Logical

Node Name

IEC 60617

graphical

symbol

Differential protection

Busbar differential protection 87BB PDIF

Breaker control function

Breaker failure protection 50BF RBRF

3I> BF

I0>BF

I2>BF

Dead zone protection 50SH-Z

Secondary system supervision

CT secondary circuit supervision

VT secondary circuit supervision 97FF

Position of circuit breaker,

disconnector and other switching

devices monitoring

3.2 Monitoring functions

Description

Self-supervision

Fault recorder

3.3 Station communication

Description

Front communication port

Isolated RS232 port

Rear communication port

0-2 isolated electrical RS485 communication ports


6

0-3 Ethernet electrical/optical communication ports

Time synchronization port

Communication protocols

IEC 61850 protocol

IEC 60870-5-103 protocol

3.4 IED software tools

Functions

Reading measuring value

Reading IED report

Setting

IED testing

Disturbance recording analysis

IED configuration

Printing

Chapter 2 General IED application

7


About this chapter

This chapter describes the use of the included software

functions in the IED. The chapter discusses general application

possibilities.


8

1 Display on LCD screen

1.1 LCD screen display function

The LCD screen displays measured analog quantities, report ouputs and

menu.

1.2 Analog display function

The analog display includes measured Ia, Ib, Ic, 3I0, Ua, Ub, Uc.

1.3 Report display function

The report display includes tripping, alarm and operation reports.

1.4 Menu dispaly function

The menu dispaly includes main menu and debugging menu, see chapter

Chapter 9 for detail.


9

2 Report record

The report record includes tripping, alarm and operation reports. See Chapter

10 general report list for detail.


10

3 Disturbance recorder

3.1 Introduction

To get fast, complete and reliable information about fault current, voltage,

binary signal and other disturbances in the power system is very important.

This is accomplished by the disturbance recorder function and facilitates a

better understanding of the behavior of the power system and related primary

and secondary equipment during and after a disturbance. An analysis of the

recorded data provides valuable information that can be used to explain a

disturbance, basis for change of IED setting plan, improvement of existing

equipment etc.

The disturbance recorder, always included in the IED, acquires sampled data

from measured analogue quantities, calculated analogue quantity, binary

input and output signals.

The function is characterized by great flexibility and is not dependent on the

operation of protection functions. It can even record disturbances not tripped

by protection functions.

The disturbance recorder information is saved for each of the recorded

disturbances in the IED and the user may use the local human machine

interface or dedicated tool to get some general information about the

recordings. The disturbance recording information is included in the

disturbance recorder files. The information is also available on a station bus

according to IEC 61850 and IEC 60870-5-103.

Fault wave recorder with great capacity, can record full process of any fault,

and can save the corresponding records. Optional data format or wave format

is provided, and can be exported through serial port or Ethernet port by

COMTRADE format.

3.2 Setting

Abbr. Explanation Default Unit Min. Max.

T_Pre Fault Time setting for recording time

before fault occurred 0.05 s 0.05 0.1

T_Post Fault Time setting for recording time

after fault occurred 0.3 s 0.50 0.45

DR_Sample Rate Sample rate for fault recording

(0: 600Hz, 1: 1200Hz) 0 0 1


11

4 Self-supervision function

The IED may test all hardware components itself, including loop out of the

relay coil. Watch can find whether or not the IED is in fault through warning

LED and warning characters which show in liquid crystal display and display

reports to tell fault type.

The method of fault elimination is replacing fault board or eliminating external

fault.

4.1 Self supervision principle

Measuring the resistance between analog circuits and ground

Measuring the output voltage in every class

Checking the zero drift and scale

Verifying alarm circuit

Verifying binary input

Checking actual live tripping including circuit breaker

Checking the setting values and parameters

4.2 Self supervision report

Table 1 Self supervision report

Abbr.(LCD Display) Description

CPU Abnormality CPU is abnormal

EquipPara Discord Equipment parameter discordance of two CPUs

SetGroup Discord Setting group discordance of two CPUs

Setting Discord Setting discordance of two CPUs

Comm Recovery Communication recovery

Call Config Fail Call configuration failure

PLC Verify Fail PLC verifying failure


12

5 Time synchroniation function

5.1 Introduction

Use the time synchronization source selector to select a common source of

absolute time for the IED when it is a part of a protection system. This makes

comparison of events and disturbance data between all IEDs in a SA system

possible.

5.2 Synchronization principle

Time definitions

The error of a clock is the difference between the actual time of the clock, and

the time the clock is intended to have. The rate accuracy of a clock is

normally called the clock accuracy and means how much the error increases,

i.e. how much the clock gains or loses time. A disciplined clock is a clock that

“knows” its own faults and tries to compensate for them, i.e. a trained clock.

Synchronization principle

From a general point of view synchronization can be seen as a hierarchical

structure. A module is synchronized from a higher level and provides

synchronization to lower levels.

A module is said to be synchronized when it periodically receives

synchronization messages from a higher level. As the level decreases, the

accuracy of the synchronization decreases as well. A module can have


13

several potential sources of synchronization, with different maximum errors,

which gives the module the possibility to choose the source with the best

quality, and to adjust its internal clock from this source. The maximum error of

a clock can be defined as a function of:

The maximum error of the last used synchronization message

The time since the last used synchronization message

The rate accuracy of the internal clock in the module.

5.2.1 Synchronization from IRIG

The built in GPS clock module receives and decodes time information from

the global positioning system. The module is located on the CPU Module. The

GPS interfaces to the IED supply two possible synchronization methods,

IRIGB and PPS (or PPM).

5.2.2 Synchronization via PPS or PPM

The IED accepts PPS or PPM to the GPS interfaces on the CPU Module.

These pulses can be generated from e.g. station master clock. If the station

master clock is not synchronized from a world wide source, time will be a

relative time valid for the substation. Both positive and negative edges on the

signal can be accepted. This signal is also considered as a fine signal.

5.2.3 Synchronization via SNTP

SNTP provides a “Ping-Pong” method of synchronization. A message is sent

from an IED to an SNTP-server, and the SNTP-server returns the message

after filling in a reception time and a transmission time. SNTP operates via the

normal Ethernet network that connects IEDs together in an IEC61850

network. For SNTP to operate properly, there must be a SNTP-server present,

preferably in the same station. The SNTP synchronization provides an

accuracy that will give 1ms accuracy for binary inputs. The IED itself can be

set as a SNTP-time server.


14

6 Setting

6.1 Introduction

Settings are divided into separate lists according to different functions. The

setting consists of two parts -setting list and communication parameters.

6.2 Operation principle

The setting procedure can be ended at any time by the key “SET” or “QUIT”.

If the key “SET” is pressed, the display shows the content of “Select”. The

range of setting zone is from 1 to 4. After confirming with the setting zone-key

“SET”, those new settings will be valid. If key “QUIT” is pressed instead, all

modifications which have been changed will be ignored.


15

7 Authorization

7.1 Introduction

To safeguard the interests of our customers, both the IED and the tools that

are accessing the IED are protected, subject of authorization handling. The

concept of authorization, as it is implemented in the IED and the associated

tools is based on the following facts:

There are two types of points of access to the IED:

local, through the local HMI

remote, through the communication ports

There are different levels (or types) of guest, super user and protection

engineer that can access or operate different areas of the IED and tools

functionality.


16

Chapter 3 Busbar differential protection

17

Chapter 3 Busbar differential

protection

About this chapter

This chapter describes the protection principle, input and output

signals, parameter, logic diagram, IED report and technical data

used for busbar differential protection.


18

1 Busbar differential protection

1.1 Introduction

Busbar differential protection represents the main protection function of the

IED. It is characterized by a high measurement accuracy as well as flexible

matching to most of busbar configurations. The operation is based on the

percentage restraint principle with an extreme stability feature against heavy

CT saturation caused by external fault.

1.2 Protection principle

1.2.1 Operation principle

Figure 1 illustrates the characteristic of busbar differential protection function.

iDiff

iRes

I_Diff

K=1

K=K_Diff

Operating zone

Figure 1 Characteristic of busbar differential protection

where:

iDiff: Busbar differential current

iRes: Busbar restraint current

I_Diff: The sensitive threshold of pickup current of busbar differential protection

K_Diff: the settable slope of the characteristic

If a short circuit occurs on the busbars whereby the same phase relation


19

applies to all infeeding currents, then the fault characteristic is a straight line

inclined at 45°. Any difference in phase relation of the fault currents leads to a

lowering of the fault characteristic. The settable slope, K_Diff is represented

as a straight line with corresponding gradient and forms the operating

characteristic.

The differential current iDiff and the restraining current iRes are calculated in the

IED according to following formula. The following definitions are applied for

each phase.

where:

n1, n2,… nn: CT transformation ratios of various feeders connected to the busbar. The IED is informed about these values by user-defined settings

The IED evaluates the differential current and the restraining current at

consecutive sampling intervals. For a continual N samples evaluating window,

the busbar protection would issue a trip command if there are more than (N-2)

samples fulfilling following condition in the program observation window:

The above mentioned calculation is performed in relevant bus zones as well

as in check zone, respectively. The trip command can be issued only when

both the faulty bus zone and the check zone are in operating area.


20

Bus

coupler

Feeder 1

S1 S2 S1 S2

Feeder 2

S1 S2

Feeder n

S1 S2

Bus

zone I

S1

Bus

zone II

S2

Check

zone

CB1 CB2CBn

CB1

CB2

CBn

CB1

CB2

CBn

CBn

CB1

CB2

Figure 2 Measurement method for the check zone, bus zone I and bus zone II

on double busbar arrangement

1.2.2 Automatic ratio compensation

CT ratios of the system may be different in various feeders, because the load

conditions may be different in the feeders. The IED adjusts CT ratio of all

feeders automatically, making the secondary currents fulfilling Krichhoff’s

current law (KCL). In order to insure the accuracy, the difference of CT ratios

among various feeders should not be more than 4 times.

1.2.3 Disconnector replica

The IED confirms the disconnector status by monitoring the disconnector

status contacts. For each disconnector, both the normally open status contact

(NO) and normally close status contact (NC) are required. Based on the

status of these two contacts, the IED can discriminate error of the contacts

and then alarm or/and block the relevant bus zone of differential protection

depending on the setting. If blocking of the protection is selected, the IED

would issue an alarm signal and would block the protection. If no blocking is


21

selected, only alarm signal would be issued and the protection would

continue to its operation according to the previous healthy state of the

disconnector before the contacts error.

1.2.4 Circuit breaker status

The feeder or coupler circuit breaker status contacts together with

disconnector status contacts are used to determine the actual bus connection

state for differential current calculation and indication of busbar connection

Both normally open status contact and normally close status contact of circuit

breakers of all feeders including bus coupler are connected to the IED. Based

on the status of these two contacts, the IED can discriminate error of the

contacts and then alarm until the error is cleared, and the protection would

continue its operation according the previous healthy state of the breaker

before the contacts error.

1.2.5 Current transformer open circuit supervision

When an open circuit occurs in secondary circuit of current transformers,

differential current appears in bus-section selective zones. Furthermore, if the

faulty current transformer corresponds to a feeder, differential current would

further appear in check zone and bus zone to which the feeder is connected.

The IED detects such a condition and issues respective alarm report.

Moreover, it is possible to block busbar differential protection when a CT open

circuit is detected.

1.2.6 Differential current saturation supervision

When an external fault occurs near the busbar, it may lead to current

transformer saturation on the faulty feeder. The resulting differential current

may cause the protection to maloperate if no measure is taken to detect

saturation condition. To cope with the problem, the IED provides a sensitive

element to detect current transformer saturation according to the waveform

characteristics of differential and restraining current.

Before the fault occurrence, current flowing through current transformers are

almost in rated value and therefore secondary current can be transformed

accurately. When the short circuit happens, still current transformer can

transform current value without saturation for short period after short circuit.

In other words, current transformers will not go into saturation immediately


22

after sever short circuit occurrence. At these instants, the differential current

is zero. The IED adopts this characteristic to detect current transformer

saturation. The free time for CT saturation detection is only 2 ms.

1.2.7 Sequence trip

In case of bus coupler with only one CT, when a fault occurs between the CT

and bus coupler circuit breaker while the circuit breaker is closed, the IED will

trip the bus section near bus coupler circuit breaker instantaneously, and after

a fixed time delay, if the bus coupler circuit breaker is opened, the IED will trip

the other bus section. The tripping logic is illustrated in Figure 3.

Bus A

IFAULT

Instantaneous trip

Line

A1

Line

B1

Line

BmLine

An

Delay trip

Bus B

Closed CB

Legend:

Figure 3 Trip logic to clear fault between coupler breaker and its CT

1.2.8 Logic diagram


23

id > (I_Diff) and id >

K_Diff · if : Busbar I


K_Diff · if : Check zone


K_Diff · if : Busbar II

&

&

Trip BusBar 1

Trip BusBar 2

Figure 4 Busbar differential protection logic diagram for double busbar arrangement

1.3 Input and output signals

IP1

IP2

IP3

Trip

CB Open

CB Close

Isolator ON

Isolator Off

Table 2 Analog input list

Signal Description

IP1 Signal for current input 1



Table 3 Binary output list

Signal Description

Trip Busbar differential protection issue trip

command

1.4 Setting parameters

1.4.1 Setting list

Table 4 Function setting list for busbar differential protection


24

NO. Default Abbr. Explanation Unit Min. Max.

1. 1 I_Diff Current setting for busbar

differential protection A 0.1 99.99

2. 0.6 K_Diff Restraint factor for busbar

differential protection 0.3 0.99

3. 0.5 I_CTFailAlm:Feeder Current setting for CT

failure alarm: feeder A 0.01 99.99

4. 0.5 I_CTFailBlk:Feeder Current setting for CT

failure blocking: feeder A 0.01 99.99

5. 0.1 I_CTFailAlm:B/C Current setting for CT

failure alarm: Bus Coupler A 0.01 99.99

6. 0.1 I_CTFailBlk:B/C

Current setting for CT

failure blocking: Bus

Coupler

A 0.01 99.99

Table 5 Binary setting list for busbar differential protection

Name Description Default Unit Min. Max.

Func_Diff ON Busbar differential protection

enabled or disabled 1 0 1

CT Fail Alarm ON CT fail alarm enabled or disabled 1 0 1

CT Fail Block ON CT fail blocking enabled or disabled 0 0 1

1.5 Reports

Table 6 Event information list

Information Description

Diff Startup differential protection startup

BZ1 Diff Tp: PhA Phase A differential protection of Bus zone 1 trip

BZ1 Diff Tp: PhB Phase B differential protection of Bus zone 1 trip

BZ1 Diff Tp: PhC Phase C differential protection of Bus zone 1 trip

BZ2 Diff Tp: PhA Phase A differential protection of Bus zone 2 trip

BZ2 Diff Tp: PhB Phase B differential protection of Bus zone 2 trip

BZ2 Diff Tp: PhC Phase C differential protection of Bus zone 2 trip

BZT Diff Tp: PhA Phase A differential protection of Transfer bus zone trip

BZT Diff Tp: PhB Phase B differential protection of Transfer bus zone trip

BZT Diff Tp: PhC Phase C differential protection of Transfer bus zone trip

1.6 Technical data


25

Table 7 Technical data for busbar differential protection

Item Rang or Value Tolerance

Differential Current 0.4 Ir to 20.00 Ir ≤ ±5% setting or ±0.02Ir

Stabilization factor 0.3 - 0.99

Differential current reset threshold 0.1 Ir

Operating time < 15ms typically at 200%

settg

Reset time < 50ms


26

Chapter 4 Circuit breaker failure protection

27

Chapter 4 Circuit breaker failure

protection

About this chapter

This chapter presents the protection principle, input and output


included in circuit breaker protection.


28

1 Circuit breaker failure protection

1.1 Introduction

The circuit breaker failure protection is able to detect a failure of the circuit

breaker during a fault clearance. It ensures fast back-up tripping of

surrounding breakers by tripping relevant bus sections.

The protection operates separately for each feeder and coupler with

dedicated settings.

Once a circuit breaker operating failure occurs on a feeder/transformer, the

bus section which the feeder/transformer is connected with can be selectively

isolated by the protection. In addition a transfer trip signal is issued to trip the

remote end circuit breaker of the feeder or other transformer windings.

In the event of a circuit breaker failure with a busbar fault, a transfer trip signal

is issued to trip the remote end circuit breaker of the feeder or other

transformer windings.

The current criteria are in combination with three phase current, zero and

negative sequence current to achieve a higher security.

2 trip stages (local and surrounding breaker tripping)

Related bus zone tripping in second stage

Transfer trip command to the remote line end in second stage

Internal/ external initiation

Single/three phase CBF initiation

Current criteria checking (including phase current, zero and negative

sequence current)


1.2.1 General description of CBF protection

Circuit breaker failure protection can be enabled or disabled for each bay in


29

the IED via binary setting. If setting “1” is applied for the corresponding bay,

CBF protection would be enabled. In this case, by operation of a protection

function, and subsequent CBF initiation by respective protection function, a

programmed timer runs toward a preset time delay limit. This time delay is set

by user under the settings, for example, “T_CBF1 Bay1”. If the circuit breaker

has not been opened after expiration of the preset time limit, the circuit

breaker failure protection issues a command to trip circuit breaker (e.g. via a

second trip coil). If the circuit breaker doesn’t respond to the repeated trip

command, until another preset delay time which is set at “T_CBF2 Bay1”, the

protection issues a trip command to isolate the fault by tripping other

surrounding backup circuit breakers (e.g. the other CBs connected to the

same bus section as the faulty CB). This operation logic and setting described

for CBF protection of bay1, is available for the other bays too and the

operation logic and settings are same as bay1.

Initiation of CBF protection can be performed by both the internal and external

protection functions. If it is desired to initiate the CBF protection by means of

external protection functions, specified binary inputs (BI) should be

marshaled. Internal protection functions can initiate the CBF protection

integrated in the IED.

The principle for breaker failure detection based on the current criterion which

is to check whether the actual current flow effectively disappeared after a

tripping command had been issued.

1.2.2 The current criterion evaluation

The current elements of the CBF protection include the phase current

detector, the zero sequence current detector and the negative sequence

current detector. If one of the three current elements is met, the current

element is open.

Since circuit breaker is supposed to be open when current disappears from

the circuit, the first criterion (current monitoring) is the most reliable way for

IED to be informed about proper operation of circuit breaker. Therefore,

current monitoring is applied to detect circuit breaker failure condition. In this

context, the monitored current of each phase is compared with the

pre-defined setting. Furthermore, it is possible to implement current checking

in case of zero-sequence ( ) and negative-sequence currents

(3I2=IA+a2IB+aIC) via binary setting. If the zero-sequence and

negative-sequence currents checking are enabled, zero sequence and

negative-sequence current are compared separately with the corresponding

settings.


30

1.2.3 Logic diagram

PhA Ini BF Bay n

PhB Ini BF Bay n

PhC Ini BF Bay n

3Ph Ini BF Bay n

Bay n CBF Chk 3I0/3I2

IA: Bay n > I_CBF:Bay n

IB: Bay n > I_CBF:Bay n

IC: Bay n > I_CBF:Bay n

3I0: Bay n > 3I0_CBF:Bay n


Bay n Func_CBF On


Diff Prot Trip: BZ1

Bay n Connected to BUS1

Diff Prot Trip: BZ2


Bay n Init from Ext CBF

IA: Bay n > 0.1In

3I0: Bay n > 0.1In

3I2: Bay n > 0.1In

IB: Bay n > 0.1In

IC: Bay n > 0.1In

T_CBF1:Bay n Trip PhA: Bay n

T_CBF2:Bay n

Trip BUS to which

Bay n connected

Trans Trip: Bay n

T_CBF1:Bay n Trip PhB: Bay n

T_CBF1:Bay n Trip PhC: Bay n

T_CBF1:Bay n Trip 3Ph: Bay n

Block AR: Bays on Bus

T_CBF2:Bay n

Trip BUS to which

Bay n connected

Trans Trip: Bay n

Block AR: Bays on Bus

OR

OR

OR

OR

OR

OR

OR

OR

OR

AND

AND

AND

AND

OR

OR

OR

OR

OR

OR

AND

AND

AND

AND

Figure 5 Logic diagram for CBF protection



31

IP1

IP2

IP3

CBF1 Trip

CBF2 Trip

PhA init BF

PhB init BF

PhC init BF

3Ph init BF


Signal Description




Table 9 Binary input list

Signal Description

PhA init BF Phase A initiate CBF protection

PhB init BF Phase B initiate CBF protection

PhC init BF Phase C initiate CBF protection

3Ph init BF Three hase initiate CBF protection


Signal Description

CBF1 Trip Circuit breaker failure protection stage 1 trip

CBF2 Trip Circuit breaker failure protection stage 2 trip

1.4 Setting parameters

1.4.1 Setting list

Table 11 Function setting list for circuit breaker failure protection


1. 1.00 I_CBF:Bay1 Phase current setting for

CBF protection of bay 1 A 0.05 100.0

2. 1.00 3I0_CBF:Bay1 Zero sequence current

setting for CBF A 0.05 100.0


32


protection of bay 1

3. 1.00 3I2_CBF:Bay1

Negative sequence

current setting for CBF

protection of bay 1

A 0.05 100.0

4. 2.00 T_CBF1:Bay1 Time delay for CBF

stage 1 of bay 1 s 0 32.00





7. 1.00 3I0_CBF:Bay2

Zero sequence current

setting for CBF

protection of bay 2

A 0.05 100.0

8. 1.00 3I2_CBF:Bay2

Negative sequence


protection of bay 2

A 0.05 100.0







12. 1.00 3I0_CBF:Bay3


setting for CBF

protection of bay 3

A 0.05 100.0

13. 1.00 3I2_CBF:Bay3

Negative sequence


protection of bay 3

A 0.05 100.0







17. 1.00 3I0_CBF:Bay4


setting for CBF

protection of bay 4

A 0.05 100.0

18. 1.00 3I2_CBF:Bay4

Negative sequence


protection of bay 4

A 0.05 100.0




33






22. 1.00 3I0_CBF:Bay5


setting for CBF

protection of bay 5

A 0.05 100.0

23. 1.00 3I2_CBF:Bay5

Negative sequence


protection of bay 5

A 0.05 100.0







27. 1.00 3I0_CBF:Bay6


setting for CBF

protection of bay 6

A 0.05 100.0

28. 1.00 3I2_CBF:Bay6

Negative sequence


protection of bay 6

A 0.05 100.0







32. 1.00 3I0_CBF:Bay7


setting for CBF

protection of bay 7

A 0.05 100.0

33. 1.00 3I2_CBF:Bay7

Negative sequence


protection of bay 7

A 0.05 100.0







37. 1.00 3I0_CBF:Bay8


setting for CBF

protection of bay 8

A 0.05 100.0


34


38. 1.00 3I2_CBF:Bay8

Negative sequence


protection of bay 8

A 0.05 100.0







42. 1.00 3I0_CBF:Bay9


setting for CBF

protection of bay 9

A 0.05 100.0

43. 1.00 3I2_CBF:Bay9

Negative sequence


protection of bay 9

A 0.05 100.0





46. 1.00 I_CBF:Bay10

Phase current setting for

CBF protection of bay

10

A 0.05 100.0

47. 1.00 3I0_CBF:Bay10


setting for CBF

protection of bay 10

A 0.05 100.0

48. 1.00 3I2_CBF:Bay10

Negative sequence



A 0.05 100.0





51. 1.00 I_CBF:Bay11



11

A 0.05 100.0

52. 1.00 3I0_CBF:Bay11


setting for CBF


A 0.05 100.0

53. 1.00 3I2_CBF:Bay11

Negative sequence



A 0.05 100.0




35




56. 1.00 I_CBF:Bay12



12

A 0.05 100.0

57. 1.00 3I0_CBF:Bay12


setting for CBF


A 0.05 100.0

58. 1.00 3I2_CBF:Bay12

Negative sequence



A 0.05 100.0





61. 1.00 I_CBF:Bay13



13

A 0.05 100.0

62. 1.00 3I0_CBF:Bay13


setting for CBF


A 0.05 100.0

63. 1.00 3I2_CBF:Bay13

Negative sequence



A 0.05 100.0





66. 1.00 I_CBF:Bay14



14

A 0.05 100.0

67. 1.00 3I0_CBF:Bay14


setting for CBF


A 0.05 100.0

68. 1.00 3I2_CBF:Bay14

Negative sequence



A 0.05 100.0






CBF protection of bay A 0.05 100.0


36


15

72. 1.00 3I0_CBF:Bay15


setting for CBF


A 0.05 100.0

73. 1.00 3I2_CBF:Bay15

Negative sequence



A 0.05 100.0





76. 1.00 I_CBF:Bay16



16

A 0.05 100.0

77. 1.00 3I0_CBF:Bay16


setting for CBF


A 0.05 100.0

78. 1.00 3I2_CBF:Bay16

Negative sequence



A 0.05 100.0





81. 1.00 I_CBF:Bay17



17

A 0.05 100.0

82. 1.00 3I0_CBF:Bay17


setting for CBF


A 0.05 100.0

83. 1.00 3I2_CBF:Bay17

Negative sequence



A 0.05 100.0





Table 12 Binary setting list for circuit breaker failure protection


Bay1 Func_CBF On CBF protection enabled or

disable for bay 1 0 0 1


37


Bay1 CBF Chk 3I0/3I2

Enable or disable the function of

checking zero and negative

sequence current for bay 1

0 0 1

Bay1 Init from Ext CBF Initiation from external CBF

function for bay 1 0 0 1







0 0 1









0 0 1









0 0 1









0 0 1









0 0 1






38






0 0 1









0 0 1









0 0 1









0 0 1









0 0 1









0 0 1






39






0 0 1









0 0 1









0 0 1









0 0 1









0 0 1



1.5 IED reports



CBF Startup CBF protection startup

CBF1 Trip CBF protection stage 1 trips

BZ1 CBF2 Trip CBF protection stage 2 of bus zone I trips


40


BZ2 CBF2 Trip CBF protection stage 2 of bus zone II trips

BZT CBF2 Trip CBF protection stage 2 of transfer bus zone issues trip command

CBF Transf.Trip The IED issues transfer trip command to the remote end of the feeder

or the other windings of transformer.

1.6 Technical data

Table 14 Technical data for circuit breaker failure protection


phase current

Negative sequence current

zero sequence current

0.08 Ir to 20.00 Ir ≤ ±3% setting or ±0.02Ir

Time delay of stage 1 0.00s to 32.00 s, step 0.01s ≤ ±1% setting or +25 ms, at

200% operating setting Time delay of stage 2 0.00s to 32.00 s, step 0.01s

Reset time of stage 1 < 20ms

Chapter 5 Dead zone protection

41


About this chapter

This chapter introduces the protection principle, input and output


included in circuit breaker failure protection.


42

1 Dead zone protection

1.1 Introduction

The IED provides this protection function to protect the area between circuit

breaker and CT in the case that CB is open, namely dead zone. Therefore, by

occurrence of a fault in dead zone, the short circuit current is measured by

protection IED while CB auxiliary contacts indicate the CB is open.


1.2.1 Function description

When one bus side CT of feeder is applied, once a fault occurs in the dead

zone, the IED trips the relevant busbar zone. Tripping logic is illustrated in

Figure 6.

Bus

IFAULT

Trip

Line1 Line2 LineN

Opened CB

Closed CB

Legend:

Figure 6 Tripping logic when applying bus side CT

When one line side CT is applied, when a fault occurs in the dead zone,

protection relay sends a transfer trip to remote end relay to isolate the fault.


43

Tripping logic is illustrated in Figure 7.

Bus

IFAULT

Relay

Inter trip

Line1 Line2 LineN

Trip

Opened CB

Closed CB

Legend:

Figure 7 Tripping logic when applying line side CT

In case of bus coupler with only one CT, when a fault occurs between the CT

and bus coupler circuit breaker while the circuit breaker is opened, the IED

will trip the bus section near the bus coupler CT instantaneously. Tripping

logic is illustrated in Figure 8.


44

Bus A

IFAULT

Instantaneous trip

Line

A1

Line

B1

Line

BmLine

An

Bus B

Opened CB

Closed CB

Legend:

Figure 8 Tripping logic for fault between coupler breaker and its CT

1.2.2 Logic diagram

PhA Ini BF Bay n

PhB Ini BF Bay n

PhC Ini BF Bay n

3Ph Ini BF Bay n


IA: Bay n > I_CBF:Bay n

IB: Bay n > I_CBF:Bay n

IC: Bay n > I_CBF:Bay n



Bay n Func_Dead Zone On


Diff Prot Trip: BZ1


Diff Prot Trip: BZ2


T_DeadZone:Bay n Trans Trip: Bay n

CB of Bay n is open

OR

AND

AND

OR

AND

Figure 9 Logic diagram for dead zone protection



45

IP1

IP2

IP3

Dead zone Trip

PhA init BF

PhB init BF

PhC init BF

3Ph init BF


Signal Description




Table 16 Binary input list

Signal Description

PhA init BF Phase A initiate CBF protection

PhB init BF Phase B initiate CBF protection

PhC init BF Phase C initiate CBF protection

3Ph init BF Three hase initiate CBF protection


Signal Description

Dead zone Trip Dead zone protection trip

1.4 Setting parameter

1.4.1 Setting list

Table 18 Function setting list for dead zone protection


1. 0.1 T_DeadZone:Bay1 Time delay of dead zone

protection for bay 1 s 0 32.00




46































Table 19 Binary setting list for dead zone protection


Bay1 Func_Dead Zone On Enable or disable the dead

zone protection for bay 1 0 0 1










47


























1.5 IED reports



DeadZone Startup Dead zone protection startup

DeadZone Trip Dead zone protection trips

1.6 Technical data

Table 21 Technical data for dead zone protection


Current 0.08 Ir to 20.00 Ir ≤ ±3% setting or ±0.02Ir

Time delay 0.00s to 32.00s, step 0.01s ≤ ±1% setting or +40 ms, at


48

200% operating setting

Chapter 6 Secondary system supervision

49

Chapter 6 Secondary system

supervision

About this chapter

This chapter describes the protection principle, input and output

signals, parameter, IED report and technical data used in

secondary system supervision function.


50

1 Current circuit supervision

1.1 Introduction

Open circuited CT cores can cause unwanted operation of differential

protection function.

The interruption on CT secondary circuit can be detected by the IED. The IED

provides following features:

One stage for alarm only

One stage for alarm and block busbar differential protection

Each stage can be selected and set separately

1.2 Function principle

1.2.1 Current circuit supervision for feeder

When an open circuit occurs in the current transformer of one feeder, the

differential currents of the check zone and the bus-section selective zone are

increasing but the restraining currents are decreasing. The IED takes use of

these features to supervise current circuit. The criterion of feeders’ CT open

circuit has two operating mode, the one is only for alarming but doesn’t block

the busbar protection and another is for alarming and blocks the busbar

protection. The two operating mode can be chosen independently.

1.2.2 Current circuit supervision for busbar coupler

When an open circuit occurs in the current transformer of the bus coupler, the

differential current and restraining current of the check zone don’t change, but

the differential currents and restraining currents of one bus-section selective

zones which the bus coupler current transformer is connected may change,

the differential currents are increasing and the restraining currents are

decreasing.

1.2.3 Logic diagram


51

id > (I_CTFailAlm:Feeder) Busbar I

id > (I_CTFailAlm:Feeder) Check zone

id > (I_CTFailAlm:Feeder) Busbar II

&

&

Alarm for busbar I

CT Fail Alarm

Func_Diff

10s

Alarm for busbar II10s

id > (I_CTFailBlk:Feeder) Busbar I

id > (I_CTFailBlk:Feeder) Check zone

id > (I_CTFailBlk:Feeder) Busbar II

&

&

Alarm busbar I and block

differential protection of busbar I 10s

10s

CT Fail Block

Alarm busbar II and block

differential protection of busbar II

Figure 10 Logic diagram for current circuit supervision of feeder

id > (I_CTFailAlm:B/C)

Busbar I

id < (I_CTFailAlm:B/C)

Check zone

id >(I_CTFailAlm:B/C)

Busbar II

&

&

Alarm for CT1

Func_Diff

10s

Alarm for CT210s

id > (I_CTFailBlk:B/C)

Busbar I

id < (I_CTFailBlk:B/C)

Check zone

id >(I_CTFailBlk:B/C)

Busbar II

&

&

Alarm CT 1 and block

differential protection of busbar I 10s

10s

CT Fail Alarm

CT Fail Block

Alarm CT 2 and block

differential protection of busbar II

Figure 11 Logic diagram for current circuit supervision of busbar coupler



52

IP1

IP2

IP3

CT Fail


Signal Description

IP1 signal for current input 1




Signal Description

CT Fail CT Fail


1.4.1 Setting list

Table 24 Function setting list for current circuit supervision protection


1. 0.5 I_CTFailAlm:Feeder Current setting for CT fail alarm

of feeder A 0.01 99.99

2. 0.5 I_CTFailBlk:Feeder Current setting for CT fail

blocking of feeder A 0.01 99.99

3. 0.1 I_CTFailAlm:B/C Current setting for CT fail alarm

of bus coupler A 0.01 99.99

4. 0.1 I_CTFailBlk:B/C Current setting for CT fail

blocking of bus coupler A 0.01 99.99

Table 25 Binary setting list for current circuit supervision protection


CT Fail Alarm ON Enable or disable the function of

CT fail alarm 0 0 1

CT Fail Block ON Enable or disable the function of

CT fail blocking 0 0 1


53

1.5 IED reports

Table 26 Alarm information list


BZ1 CT Fail: PhA CT failure of phase A of bus zone 1

BZ2 CT Fail: PhA CT failure of phase A of bus zone 2

BZT CT Fail: PhA CT failure of phase A of transfer bus zone

B/C CT Fail: PhA CT failure of phase A of bus coupler

BZ1 CT Fail: PhB CT failure of phase B of busbar 1

BZ2 CT Fail: PhB CT failure of phase B of busbar 2

BZT CT Fail: PhB CT failure of phase B of transfer busbar

B/C CT Fail: PhB CT failure of phase B of bus coupler

BZ1 CT Fail: PhC CT failure of phase C of busbar 1

BZ2 CT Fail: PhC CT failure of phase C of busbar 2

BZT CT Fail: PhC CT failure of phase C of transfer busbar

B/C CT Fail: PhC CT failure of phase C of bus coupler


54

2 Fuse failure supervision VT

2.1 Introduction

To monitor the voltage value of the system, the IED can accept the voltage

connected. Accordingly, a measured voltage failure, due to a broken

conductor or a short circuit fault in the secondary circuit of voltage transformer,

can be monitored completely. The features of the function are as follows:

2.2 Function principle

VT failure supervision function can be enabled or disabled through binary

setting “Bus Voltage Connected”. By applying this setting, VT failure

supervision function would monitor the voltage transformer circuit. As

mentioned, the function is able to detect single-phase broken, two-phase

broken or three-phase broken faults in secondary circuit of voltage

transformer.

There are three main criteria for VT failure detection; the first is dedicated to

detect three-phase broken faults. The second and third ones are to detect

single or two-phase broken faults in solid earthed systems.

2.2.1 Three phases (symmetrical) VT Fail

The maximum of three phase-to-earth voltages is less than 8 V, and at the

same time, the busbar should be running. The alarm signal will be issued

after the criterion is met for 10s.

2.2.2 Single/two phases (asymmetrical) VT Fail

The calculated zero sequence voltage 3U0 is more than the 7 V. This

condition may correspond to single or two-phase broken fault in secondary

circuit of the voltage transformer, if the system starpoint is solidly earthed and

no startup element has been detected. The alarm signal will be issued after

the criterion is met for 10s.

2.2.3 Logic diagram


55

10S

Max

Alarm for busbar I

{Ua,Ub,Uc}<8V:

busbar I

Busbar running: busbar I

AND

3U0>7V: Busbar I

OR

10S

Max

Alarm for busbar II

{Ua,Ub,Uc}<8V:

busbar II

Busbar running: busbar II

AND

3U0>7V: Busbar II

OR

Figure 12 VT Logic diagram of VT failure supervision


IP1

IP2

IP3

UP1

UP2

UP3

VT Fail


Signal Description




UP1 signal for voltage input 1




Signal Description

VT Fail VT fail


56


2.4.1 Setting list

Table 29 Binary setting list for fuse failure supervision protection


Bus Voltage

Connected

Enable or disable busbar voltage

connection 0 0 1

2.5 IED reports

Table 30 Alarm information list


BZ1 VT Fail VT failure in circuit of voltage transformer of bus zone 1

BZ2 VT Fail VT failure in circuit of voltage transformer of bus zone 2

BZT VT Fail VT failure in circuit of voltage transformer of transfer busbar

2.6 Technical data

Table 31 Technical data for VT secondary circuit supervision

Item Range or value Tolerances

Minimum current 0.08Ir to 0.20Ir, step 0.01A ≤ ±3% setting or ±0.02Ir

Minimum zero or negative

sequence current

0.08Ir to 0.20Ir, step 0.01A ≤ ±5% setting or ±0.02Ir

Maximum phase to earth voltage 7.0V to 20.0V, step 0.01V ≤ ±3% setting or ±1 V

Maximum phase to phase

voltage

10.0V to 30.0V, step 0.01V ≤ ±3% setting or ±1 V

Normal phase to earth voltage 40.0V to 65.0V, step 0.01V ≤ ±3% setting or ±1 V


57

3 Auxiliary contacts of circuit breaker and disconnector supervision

The IED is connected with normally open contacts and normally close

contacts of circuit breakers and disconnectors. It performs monitoring on the

received information to detect any implausible status.

If such a wrong status is detected for a disconnector, the IED will announce it

after a settable time delay and continue to operate according to previous

healthy state of disconnector contacts. If the blocking function is enabled in

binary setting, the relevant bus zone of the busbar differential protection

would be blocked until the wrong status changing to normal. Otherwise, the

relevant bus zone of the busbar differential protection would not be blocked.

If such a wrong status is detected for a circuit breaker, the IED announces it

after a settable time delay and the protection will not be blocked and continue

to operate according to previous healthy state of circuit breaker.


58

Chapter 7 Monitoring function

59


About this chapter

This chapter describes the protection principle, input and

output signals, parameter, IED report and technical data used

in monitoring function.


60

1 Self-supervision

All modules can perform self-supervision to its key hardware components

and program as soon as energizing. Parts of the modules are

self-supervised in real time. All internal faults or abnormal conditions will

initiate an alarm. The fatal faults among them will result in the whole IED

blocked

CPU module and communication module perform real time

inter-supervision. Therefore communication interruption between them is

detected and related alarm will be given

CRC checks for the setting, program and configuration, etc.

Chapter 8 Station communication

61


About this chapter

This chapter describes the communication possibilities in a

SA-system.


62

1 Overview

Each IED is provided with a communication interface, enabling it to connect to

one or many substation level systems or equipment.

Following communication protocols are available:

IEC 61850-8-1 communication protocol

60870-5-103 communication protocol

The IED is able to connect to one or more substation level systems or

equipments simultaneously, through the communication ports with

communication protocols supported.

1.1 Protocol

1.1.1 IEC61850-8 communication protocol

IEC 61850-8-1 allows two or more intelligent electronic devices (IEDs) from

one or several vendors to exchange information and to use it in the

performance of their functions and for correct co-operation.

GOOSE (Generic Object Oriented Substation Event), which is a part of IEC

61850-8-1 standard, allows the IEDs to communicate state and control

information amongst themselves, using a publish-subscribe mechanism. That

is, upon detecting an event, the IED(s) use a multi-cast transmission to notify

those devices that have registered to receive the data. An IED can, by

publishing a GOOSE message, report its status. It can also request a control

action to be directed at any device in the network.

1.1.2 IEC60870-5-103 communication protocol

The IEC 60870-5-103 communication protocol is mainly used when a

protection IED communicates with a third party control or monitoring system.

This system must have software that can interpret the IEC 60870-5-103

communication messages.

The IEC 60870-5-103 is an unbalanced (master-slave) protocol for coded-bit

serial communication exchanging information with a control system. In IEC

terminology a primary station is a master and a secondary station is a slave.


63

The communication is based on a point-to-point principle. The master must

have software that can interpret the IEC 60870-5-103 communication

messages. For detailed information about IEC 60870-5-103, refer to the

“IEC60870 standard” part 5: “Transmission protocols”, and to the section 103:

“Companion standard for the informative interface of protection equipment”.

1.2 Communication port

1.2.1 Front communication port

There is a serial RS232 port on the front plate of all the IEDs. Through this

port, the IED can be connected to the personal computer for setting, testing,

and configuration using the dedicated Sifang software tool.

1.2.2 RS485 communication ports

Up to 2 isolated electrical RS485 communication ports are provided to

connect with substation automation system. These two ports can work in

parallel for IEC60870-5-103.

1.2.3 Ethernet communication ports

Up to 3 electrical or optical Ethernet communication ports are provided to


parallel for one protocol, IEC61850 or IEC60870-5-103.

1.3 Technical data


Item Data

Number 1

Connection Isolated, RS232; front panel,

9-pin subminiature connector, for software tools

Communication speed 9600 baud

Max. length of communication cable 15 m


64

RS485 communication port

Item Data

Number 0 to 2

Connection 2-wire connector

Rear port in communication module

Max. length of communication cable 1.0 km

Test voltage 500 V AC against earth

For IEC 60870-5-103 protocol

Communication speed Factory setting 9600 baud,

Min. 1200 baud, Max. 19200 baud

Ethernet communication port

Item Data

Electrical communication port

Number 0 to 3

Connection RJ45 connector


Max. length of communication cable 100m

For IEC 61850 protocol

Communication speed 100 Mbit/s



Optical communication port ( optional )

Number 0 to 2

Connection SC connector


Optical cable type Multi-mode

Max. length of communication cable 2.0km

IEC 61850 protocol




Time synchronization


65

Item Data

Mode Pulse mode

IRIG-B signal format IRIG-B000



Voltage levels differential input

1.4 Typical substation communication scheme

The IED is able to connect to one or more substation level systems or

equipments simultaneously, through the communication ports with

communication protocols supported.

Gateway

or

converter

Work Station 3

Server or

Work Station 1

Server or

Work Station 2

Work Station 4

Net 2: IEC61850/IEC103,Ethernet Port B

Net 3: IEC103, RS485 Port A

Net 4: IEC103, RS485 Port B

Net 1: IEC61850/IEC103,Ethernet Port A

Gateway

or

converter

SwitchSwitch Switch

Switch

Switch

Switch

Figure 13 Connection example for multi-networks of station automation system

1.5 Typical time synchronizing scheme

All IEDs feature a permanently integrated electrical time synchronization port

(shown in Figure 14). It can be used to feed timing telegrams in IRIG-B or

pulse format into the IEDs via time synchronization receivers. The IED can

adapt the second or minute pulse in the pulse mode automatically.

Meanwhile, SNTP network time synchronization can be applied.


66

SNTP IRIG-B Pulse

Ethernet port IRIG-B port Binary input

Figure 14 Time synchronizing modes

Chapter 9 Hardware

67

Chapter 9 Hardware

About this chapter

This chapter describes the IED hardware.

Chapter 9 Hardware

68

1 Introduction

1.1 IED structure

The enclosure for protection IED is 19 inches in width and 8U in height, for

the auxiliary case is 19 inches in width and 4U in height.

The IED is flush mounting with panel cutout and cabinet.

Connection terminals to other system on the rear.

The front panel of IED is aluminum alloy by founding in integer and

overturn downwards. LCD, LED and setting keys are mounted on the

panel. There is a serial interface on the panel suitable for connecting a

PC.

Draw-out modules for serviceability are fixed by lock component.

The modules can be combined through the bus on the rear board. Both

the IED and the other system can be combined through the rear

interfaces.

1.2 IED module arrangement

Chapter 9 Hardware

69

CAN

Test

port

AIM

AIM

AIM

AIM

AIM

AIM

AIM

BO

M

CP

U2

CP

U1

BO

M

PS

M

BO

M

BO

M

BO

M

BIM

BO

M

PS

M

CO

M

X1X2X3X4X5X6X7X9

X10X11X13X14X15X16X17X18X19

X8

X12

Figure 15 Rear view of the protection 8U IED

BIM

PS

M

BO

M

BO

M

BO

M

BO

M

BIM

X23X27X28X29X30X31X32

CAN

X33

X26 X25

BIM

X21

BIM

X20

BIM

X24

BO

M

BIM

BIM

X22

Figure 16 Rear view of the protection 4U IED

Chapter 9 Hardware

70

2 Local human-machine interface

2.1 Introduction

The human-machine interface is simple and easy to understand – the whole

front plate is divided into zones, each of which has a well-defined

functionality:

1

2

3

45

68 7

Figure 17 The view of IED front plate

1. Liquid crystal display (LCD)

2. LEDs

3. Shortcut function keys

4. Arrow keys

5. Reset key

6. Quit key

Chapter 9 Hardware

71

7. Set key

8. RS232 communication port

2.2 Liquid crystal display (LCD)

The LCD back light of HMI is blue, 5 lines with up to 28 characteristics per line

can be displayed.

When operating keys are pressed or in the case of IED alarming or operating

report appearance, the back light will turn on automatically until the preset

time delay elapse after the latest operation or alarm.

2.3 LED

There are 8 LEDs on the left side of the LCD.

2.4 Keyboard

The keyboard is used to monitor and operate IED. The keyboard has the

same look and feel in CSC family. As shown in Figure 17, keyboard is divided

into Arrow keys, Reset key, Quit key and Set key. The specific instructions on

the keys as the following table described:

Table 32 HMI keys on the front of the IED

Key Function

Up arrow key Move up in menu

Page up between screens

Increase value in setting

Down arrow key Move down in menu

Page down between screens

Decrease value in setting

Left arrow key Move left in menu

Right arrow key Move Right in menu

Reset key Reset the LEDs

Return to normal scrolling display state directly

Set key Enter main menu or submenu

Confirm the setting change

Quit key Back to previous menu

Cancel the current operation and back to previous menu

Chapter 9 Hardware

72

Key Function

Return to scrolling display state

Lock or unlock current display in the scrolling display state (the

lock state is indicated by a "solid diamond" type icon on the botton

right corner of the LCD)

2.5 IED menu

2.5.1 Menu construction

Chapter 9 Hardware

73

OpStatus

Settings

QueryRep

Setup

Testing

AI

BI

Measure

Status

Version

CommPara BaudR485

EventRpt

AdjScale

SimuReSig

SwSetGrp

ViewScale

ViewDrift

SOEReset

AlarmRpt

ModifyPW

MainMenu Protocol

EquipCode

BayName EquipPara

StartRpt Log

SetPrint

AdjDrift

PrtSample

CommAddr

TimeMode

ProSet

ProContwd

103Type

Test BO

Set Time Cur Time Set Time

Contrast

Table 33 Full name for the menu

Sub-menu Full name Sub-sub menu Full name

OpStatus Operation status AI Analog input

Status IED status

Chapter 9 Hardware

74

Sub-menu Full name Sub-sub menu Full name

Version IED version

EquipCode Equipment code

BI Binary input

Measure Measurement values

Settings Settings

CommPara Communication parameter

BayName Bay name

CommAddr Communication address

TimeMode Time mode

BaudR485 Baud rate of 485 port

EquipPara Equipment parameter

ProSet Protection setting

ProContwd Protection binary setting

QueryRep Query report

EventRpt Event report

StartRpt Startup report

AlarmRpt Alarm report

Log Operating log

Setup IED setup

SOEReset SOE reset

Protocol protocol

ModifyPW Modify password

SetPrint Print setup

103Type 103 protocol

Test BO Test binary output

Set Time Set time Cur Time Current time

Set Time Set time

Testing Testing

SimuReSig Simulate remote signal

SwSetGrp Switch setting group

ViewDrift View zero drift

AdjDrift Adjust zero drift

ViewScale View scale

AdjScale Adjust scale

PrtSample Print sample data

Contrast LCD contrast

2.5.2 Operation status

Sub menu Sub-sub menu Explanation

OpStatus

AI Read the secondary analogure of the selected CPU

module

Status Read the IED status

Version Read the IED type, date and CPU version

EquipCode Read the versions, released time and CSC code of all

Chapter 9 Hardware

75


modules

BI Read the current status of binary inputs,

Measure Read the analogure value and calculation value

2.5.3 Settings


Settings

CommPara Communication parameter

BayName Enter into the bay name

CommAddr Enter into the communication address

TimeMode Time mode

BaudR485 Select the baud rate of 485 port

EquipPara Enter into the equipment parameter

ProSet Protection setting

ProContwd Protection binary setting

2.5.4 Query report

Sub

menu

Sub-sub menu Sub-sub-sub

menu

Explanation

QueryRpt

EventRpt

Latest Rpt Search the latest event report, press the

Set key to see the report

Last 6 Rpts Search the latest six event reports, press

the Set key to see the report

Search by Date Search the reports by date

AlarmRpt Last 6 Rpts

Search the latest six alarm reports, press



StartRpt

Latest Rpt Query the latest event report, press the

Set key to see the report

Last 6 Rpts Query the latest six event reports, press


QueryRpt by Date Query the reports by date

Log Last 6 Rpts

Search the latest six operation reports,

press the Set key to see the report


2.5.5 Setup

Chapter 9 Hardware

76

Sub

menu


menu

Explanation

Setup

SOE_Reset

Manual Reset

Automatic

Reset

Protocol If communication with automation system

via RS485 port, this item can be ignored

ModifyPW The fatory password: 8888

103Type IEC60870-5-103 code

2.5.6 Test BO


Test BO Test binary output

2.5.7 Set Time

Sub

menu


menu

Explanation

Set time Cur Time

Modify the time with arrow keys Set Time

2.5.8 Testing

Sub

menu


menu

Explanation

Testing

SimuReSig

Simu Alarm

Using“√” or “X” to select the simulation point

Simu Linker

TransRecData

Simu Trip

Simu BI

Simu MST

Alarm

ViewDrift

Enter into the CPU number

ViewScale

PrtSample

SwSetGr

AdjDrift

AdjScale

Chapter 9 Hardware

77

2.5.9 Contrast

Sub

menu


menu

Explanation

Contrast TestEffect Modify the contrast with arrow keys

Chapter 9 Hardware

78

3 Analog input module

3.1 Introduction

The AI module functions are to transform the secondary signals, from voltage

and current transformers in power system, into weak electric signals, and

perform isolation and anti-interference.

3.2 Terminals of analog input module

The Analogue Input Module A

b01 a01

b02 a02

b03 a03

a04b04

a05b05

a06b06

a07b07

a08b08

a09b09

a10b10

a11b11

ab

Figure 18 Terminals arrangement of AIM A

Table 34 Description of terminals of AIM A

Terminal Analogue

Input Remark

a01 I1 Star point

b01 I’1

a02 I2 Star point

b02 I’2

a03 Null

b03 Null

Chapter 9 Hardware

79

a04 Null

b04 Null

a05 U3B Star point

b05 U3C Star point

a06 U3A Star point

b06 U3N

a07 U2B Star point

b07 U2C Star point

a08 U2A Star point

b08 U2N

a09 U1B Star point

b09 U1C Star point

a10 U1A Star point

b10 U1N

a11 Null

b11 Null

The Analogue Input Module H

b01 a01

b02 a02

b03 a03

a04b04

a05b05

a06b06

a07b07

a08b08

b09

b10

b11

ab

a10

a11

a09

Figure 19 Terminals arrangement of AIM H

Table 35 Description of terminals of AIM H

Chapter 9 Hardware

80

Terminal Analogue

Input Remark

a01 I1 Star point

b01 I’1

a02 I2 Star point

b02 I’2

a03 I3 Star point

b03 I’3

a04 I4 Star point

b04 I’4

a05 I5 Star point

b05 I’5

a06 I6 Star point

b06 I’6

a07 I7 Star point

b07 I’7

a08 I8 Star point

b08 I’8

a09 I9 Star point

b09 I’9

a10 I10 Star point

b10 I’10

a11 Null

b11 Null

3.3 Technical data

Internal current transformer

Item Standard Data

Rated current Ir IEC 60255-1 1 or 5 A

Nominal current range 0.05 Ir to 30 Ir

Nominal current range of sensitive

CT

0.005 to 1 A

Power consumption (per phase) ≤ 0.1 VA at Ir = 1 A;

Chapter 9 Hardware

81

≤ 0.5 VA at Ir = 5 A

≤ 0.5 VA for sensitive CT

Thermal overload capability IEC 60255-1

IEC 60255-27

100 Ir for 1 s

4 Ir continuous

Thermal overload capability for

sensitive CT

IEC 60255-27

DL/T 478-2001

100 A for 1 s

3 A continuous

Internal voltage transformer

Item Standard Data

Rated voltage Vr (ph-ph) IEC 60255-1 100 V /110 V

Nominal range (ph-e) 0.4 V to 120 V

Power consumption at Vr = 110 V IEC 60255-27

DL/T 478-2001

≤ 0.1 VA per phase

Thermal overload capability

(phase-neutral voltage)

IEC 60255-27

DL/T 478-2001

2 Vr, for 10s

1.5 Vr, continuous

Chapter 9 Hardware

82

4 Communication module

4.1 Introduction

The communication module performs communication between the internal

protection system and external equipments such as HMI, engineering

workstation, substation automation system, RTU, etc., to transmit remote

metering, remote signaling, SOE, event reports and record data.

4.2 Terminals of communication module

01

02

03

04

05

06

07

08

09

10

11

12

13

14

15

16

Ethernet port B

Ethernet port A

Ethernet port C

Figure 20 Terminals arrangement of COM

Table 36 Definition of terminals of COM

Terminal Definition

01 Null

02 Null

03 Null

04 Null

05 Optional RS485 port - 2B

Chapter 9 Hardware

83

06 Optional RS485 port - 2A

07 Optional RS485 port - 1B

08 Optional RS485 port - 1A

09 Time synchronization

10 Time synchronization GND

11 Null

12 Null

13 Null

14 Null

15 Null

16 Null

Ethernet

Port A

Optional optical fiber or RJ45

port for station automation

system

Ethernet

Port B



system

Ethernet

Port C



system

4.3 Substaion communication port


There is a serial RS232 port on the front plate of all the IEDs. Through this

port, the IED can be connected to the personal computer for setting, testing,

and configuration using the dedicated Sifang software tool.


Up to 2 isolated electrical RS485 communication ports are provided to


parallel for IEC60870-5-103.

4.3.3 Ethernet communication ports

Chapter 9 Hardware

84

Up to 3 electrical or optical Ethernet communication ports are provided to

connect with substation automation system. Two out of these three ports can

work in parallel for protocol, IEC61850 or IEC60870-5-103.

4.3.4 Time synchronization port

All IEDs feature a permanently integrated electrical time synchronization port.

It can be used to feed timing telegrams in IRIG-B or pulse format into the

IEDs via time synchronization receivers. The IED can adapt the second or

minute pulse in the pulse mode automatically.

Meanwhile, SNTP network time synchronization can also be applied.

4.4 Technical data


Item Data

Number 1

Connection Isolated, RS232; front panel,

9-pin subminiature connector, for software tools

Communication speed 9600 baud

Max. length of communication cable 15 m

RS485 communication port

Item Data

Number 0 to 2



Max. length of communication cable 1.0 km

Test voltage 500 V AC against earth


Communication speed Factory setting 9600 baud,

Min. 1200 baud, Max. 19200 baud

Ethernet communication port

Chapter 9 Hardware

85

Item Data

Electrical communication port

Number 0 to 3

Connection RJ45 connector


Max. length of communication cable 100m

For IEC 61850 protocol




Optical communication port ( optional )

Number 0 to 2

Connection SC connector


Optical cable type Multi-mode

Max. length of communication cable 2.0km

IEC 61850 protocol




Time synchronization

Item Data

Mode Pulse mode

IRIG-B signal format IRIG-B000



Voltage levels differential input

Chapter 9 Hardware

86

5 Binary input module

5.1 Introduction

The binary input module is used to connect the input signals and alarm

signals such as the auxiliary contacts of the circuit breaker (CB), etc.

5.2 Terminals of binary input module

The Binary Input Module A

c02 a02

c04 a04

c06 a06

a08c08

a10c10

a12c12

a14c14

a16c16

a18c18

a20c20

a22c22

a24c24

a26c26

a28c28

a30c30

a32c32

ac

DC -DC -

Figure 21 Terminals arrangement of BIM A

Table 37 Definition of terminals of BIM A

Terminal Definition Remark

Chapter 9 Hardware

87

a02 BI1 BI group 1

c02 BI2 BI group 2

a04 BI3 BI group 1

c04 BI4 BI group 2

a06 BI5 BI group 1

c06 BI6 BI group 2

a08 BI7 BI group 1

c08 BI8 BI group 2

a10 BI9 BI group 1

c10 BI10 BI group 2

a12 BI11 BI group 1

c12 BI12 BI group 2

a14 BI13 BI group 1

c14 BI14 BI group 2

a16 BI15 BI group 1

c16 BI16 BI group 2

a18 BI17 BI group 1

c18 BI18 BI group 2

a20 BI19 BI group 1

c20 BI20 BI group 2

a22 BI21 BI group 1

c22 BI22 BI group 2

a24 BI23 BI group 1

c24 BI24 BI group 2

a26 BI25 BI group 1

c26 BI26 BI group 2

a28 BI27 BI group 1

c28 BI28 BI group 2

a30 BI29 BI group 1

c30 BI30 BI group 2

a32 DC - Input

Common

terminal of BI

group 1

c32 DC - Input

Common

terminal of BI

group 2

Chapter 9 Hardware

88

The Binary Input Module B

c02 a02

c04 a04

c06 a06

a08c08

a10c10

a12c12

a14c14

a16c16

a18c18

a20c20

a22c22

a24c24

a26c26

a28c28

a30c30

a32c32

ac

DC -DC -

DC +DC +

Figure 22 Terminals arrangement of BIM B

Table 38 Definition of terminals of BIM B

Terminal Definition Remark

a02 DC + Input DC input voltage

c02 DC + Input DC input voltage

a04 BI1

c04 BI2

a06 BI3

c06 BI4

a08 BI5

c08 BI6

a10 BI7

Chapter 9 Hardware

89

c10 BI8

a12 BI9

c12 BI10

a14 BI11

c14 BI12

a16 BI13

c16 BI14

a18 BI15

c18 BI16

a20 BI17

c20 BI18

a22 BI19

c22 BI20

a24 BI21

c24 BI22

a26 BI23

c26 BI24

a28 BI25

c28 BI26

a30 BI27

c30 BI28

a32 DC - Input Common

terminal of all BI

c32 DC - Input Common

terminal of all BI

5.3 Technical data

Item Standard Data

Input voltage range IEC60255-1 110/125 V

220/250 V

Threshold1: guarantee

operation

IEC60255-1 154V, for 220/250V

77V, for 110V/125V

Threshold2: uncertain operation IEC60255-1 132V, for 220/250V ;

66V, for 110V/125V

Response time/reset time IEC60255-1 Software provides de-bounce

Chapter 9 Hardware

90

time

Power consumption, energized IEC60255-1 Max. 0.5 W/input, 110V

Max. 1 W/input, 220V

Chapter 9 Hardware

91

6 Binary output module

6.1 Introduction

The binary output modules mainly provide tripping output contacts, initiating

output contacts and signaling output contacts. All the tripping output relays

have contacts with a high switching capacity and are blocked by protection

startup elements.

Each output relay can be configured to satisfy the demands of users.

6.2 Terminals of binary output module

Binary Output Module A

The module provides 16 output relays for tripping or initiating, with total 16 contacts.

Chapter 9 Hardware

92

a02

R

1

a04

a06

a08

a10

a12

a14

a16

a18

a20

a22

a24

a26

a28

a30

a32

ac

c02

c04

c06

c08

c10

c12

c14

c16

c18

c20

c22

c24

c26

c28

c30

c32

R

3

R

5

R

7

R

9

R

11

R

13

R

15

R

16

R

2

R

4

R

6

R

8

R

10

R

12

R

14

Figure 23 Terminals arrangement of BOM A

Chapter 9 Hardware

93

Table 39 Definition of terminals of BOM A

Terminal Definition Related relay

a02 Trip contact 1-0 Output relay 1

c02 Trip contact 1-1 Output relay 1































Chapter 9 Hardware

94

Binary Output Module B

The module provides 32 output relays for tripping or initiating, with total 32

contacts, equal to double binary output module A bound together.

a02

R

1

a04

a06

a08

a10

a12

a14

a16

a18

a20

a22

a24

a26

a28

a30

a32

ac

c02

c04

c06

c08

c10

c12

c14

c16

c18

c20

c22

c24

c26

c28

c30

c32

R

3

R

5

R

7

R

9

R

11

R

13

R

15

R

16

R

2

R

4

R

6

R

8

R

10

R

12

R

14

Figure 24 Terminals arrangement of BOM B

Chapter 9 Hardware

95

Table 40 Definition of terminals of BOM B


BOM B-1

































Chapter 9 Hardware

96


BOM B-2

































Chapter 9 Hardware

97

6.3 Technical data

Item Standard Data

Max. system voltage IEC60255-1 250V /~

Current carrying capacity IEC60255-1 5 A continuous,

30A，200ms ON, 15s OFF

Making capacity IEC60255-1 1100 W( ) at inductive load with

L/R>40 ms

1000 VA(AC)

Breaking capacity IEC60255-1 220V , 0.15A, at L/R≤40 ms

110V , 0.30A, at L/R≤40 ms

Mechanical endurance, Unloaded IEC60255-1 50,000,000 cycles (3 Hz switching

frequency)

Mechanical endurance, making IEC60255-1 ≥1000 cycles

Mechanical endurance, breaking IEC60255-1 ≥1000 cycles

Specification state verification IEC60255-1

IEC60255-23

IEC61810-1

UL/CSA、TŰV

Contact circuit resistance

measurement

IEC60255-1

IEC60255-23

IEC61810-1

30mΩ

Open Contact insulation test (AC

Dielectric strength)

IEC60255-1

IEC60255-27

AC1000V 1min

Maximum temperature of parts and

materials

IEC60255-1 55℃

Chapter 9 Hardware

98

7 Power supply module

7.1 Introduction

The power supply module is used to provide the correct internal voltages and

full isolation between the terminal and the battery system.

7.2 Terminals of power supply module

c02 a02

c04 a04

c06 a06

a08c08

a10c10

a12c12

a14c14

a16c16

a18c18

a20c20

a22c22

a24c24

a26c26

a28c28

a30c30

a32c32

ac

DC 24V +

OUTPUTS

DC 24V -

OUTPUTS

AUX.DC +

INPUT

AUX. DC -

INPUT

Figure 25 Terminals arrangement of PSM

Table 41 Definition of terminals of PSM

Terminal Definition

a02 AUX.DC 24V+ output 1

c02 AUX.DC 24V+ output 2

Chapter 9 Hardware

99

a04 AUX.DC 24V+ output 3

c04 AUX.DC 24V+ output 4

a06 Isolated terminal, not wired

c06 Isolated terminal, not wired

a08 AUX.DC 24V- output 1

c08 AUX.DC 24V- output 2





a14 Alarm contact A1, for

AUX.DC power input failure

c14 Alarm contact A0, for


a16 Alarm contact B1, for


c16 Alarm contact B0, for




a20 AUX. power input 1, DC +

c20 AUX. power input 2, DC +

a22 AUX. power input 3, DC +

c22 AUX. power input 4, DC +



a26 AUX. power input 1, DC -

c26 AUX. power input 2, DC -

a28 AUX. power input 3, DC -

c28 AUX. power input 4, DC -



a32 Terminal for earthing

c32 Terminal for earthing

Chapter 9 Hardware

100

7.3 Technical data

Item Standard Data

Rated auxiliary voltage Uaux IEC60255-1 110 to 250V

Permissible tolerance IEC60255-1 ±%20 Uaux

Power consumption at quiescent

state

IEC60255-1 ≤ 50 W per power supply module

Power consumption at maximum

load

IEC60255-1 ≤ 60 W per power supply module

Inrush Current IEC60255-1 T ≤ 10 ms/I≤ 25 A per power supply

module,

Chapter 9 Hardware

101

8 Technical data

8.1 Type tests

Insulation test

Item Standard Data

Over voltage category IEC60255-27 Category III

Pollution degree IEC60255-27 Degree 2

Insulation IEC60255-27 Basic insulation

Degree of protection (IP) IEC60255-27

IEC 60529

Front plate: IP40

Rear, side, top and bottom: IP 30

Power frequency high voltage

withstand test

IEC 60255-5

EN 60255-5

ANSI C37.90

GB/T 15145-2001

DL/T 478-2001

2KV, 50Hz

2.8kV

between the following circuits:

auxiliary power supply

CT / VT inputs

binary inputs

binary outputs

case earth

500V, 50Hz

between the following circuits:

Communication ports to case

earth

time synchronization terminals

to case earth

Impulse voltage test IEC60255-5

IEC 60255-27

EN 60255-5

ANSI C37.90

GB/T 15145-2001

DL/T 478-2001

5kV (1.2/50μs, 0.5J)

If Ui≥63V

1kV if Ui<63V

Tested between the following

circuits:


CT / VT inputs

binary inputs

binary outputs

case earth

Note: Ui: Rated voltage

Insulation resistance IEC60255-5 ≥ 100 MΩ at 500 V

Chapter 9 Hardware

102

IEC 60255-27

EN 60255-5

ANSI C37.90

GB/T 15145-2001

DL/T 478-2001

Protective bonding resistance IEC60255-27 ≤ 0.1Ω

Fire withstand/flammability IEC60255-27 Class V2

Electromagnetic compatibility tests

Item Standard Data

1 MHz burst immunity test IEC60255-22-1

IEC60255-26

IEC61000-4-18

EN 60255-22-1

ANSI/IEEE C37.90.1

Class III

2.5 kV CM ; 1 kV DM

Tested on the following circuits:


CT / VT inputs

binary inputs

binary outputs

1 kV CM ; 0 kV DM


communication ports

Electrostatic discharge IEC 60255-22-2

IEC 61000-4-2

EN 60255-22-2

Level 4

8 kV contact discharge;

15 kV air gap discharge;

both polarities; 150 pF; Ri = 330 Ω

Radiated electromagnetic field

disturbance test

IEC 60255-22-3

EN 60255-22-3

Frequency sweep:

80 MHz – 1 GHz; 1.4 GHz – 2.7 GHz

spot frequencies:

80 MHz; 160 MHz; 380 MHz; 450

MHz; 900 MHz; 1850 MHz; 2150

MHz

10 V/m

AM, 80%, 1 kHz

Radiated electromagnetic field

disturbance test

IEC 60255-22-3

EN 60255-22-3

Pulse-modulated

10 V/m, 900 MHz; repetition rate

200 Hz, on duration 50 %

Electric fast transient/burst immunity

test

IEC 60255-22-4,

IEC 61000-4-4

EN 60255-22-4

Class A, 4KV



Chapter 9 Hardware

103

ANSI/IEEE C37.90.1 CT / VT inputs

binary inputs

binary outputs

Class A, 1KV


communication ports

Surge immunity test IEC 60255-22-5

IEC 61000-4-5

4.0kV L-E

2.0kV L-L



CT / VT inputs

binary inputs

binary outputs

500V L-E


communication ports

Conduct immunity test IEC 60255-22-6

IEC 61000-4-6

Frequency sweep: 150 kHz – 80

MHz

spot frequencies: 27 MHz and 68

MHz

10 V

AM, 80%, 1 kHz

Power frequency immunity test IEC60255-22-7 Class A

300 V CM

150 V DM

Power frequency magnetic field test IEC 61000-4-8 Level 4

30 A/m cont. / 300 A/m 1 s to 3 s

100 kHz burst immunity test IEC61000-4-18 2.5 kV CM ; 1 kV DM



CT / VT inputs

binary inputs

binary outputs

1 kV CM ; 0 kV DM


communication ports

Mechanical tests

Chapter 9 Hardware

104

Item Standard Data

Sinusoidal Vibration response

test

IEC60255-21-1

EN 60255-21-1

Class 1

10 Hz to 60 Hz: 0.075 mm

60 Hz to 150 Hz: 1 g

1 sweep cycle in each axis

Relay energized

Sinusoidal Vibration endurance

test

IEC60255-21-1

EN 60255-21-1

Class 1

10 Hz to 150 Hz: 1 g

20 sweep cycle in each axis

Relay non-energized

Shock response test IEC60255-21-2

EN 60255-21-2

Class 1

5 g, 11 ms duration

3 shocks in both directions of 3 axes

Relay energized

Shock withstand test IEC60255-21-2

EN 60255-21-2

Class 1

15 g, 11 ms duration

3 shocks in both directions of 3 axes

Relay non-energized

Bump test IEC60255-21-2 Class 1

10 g, 16 ms duration

1000 shocks in both directions of 3

axes

Relay non-energized

Seismic test IEC60255-21-3 Class 1

X-axis 1 Hz to 8/9 Hz: 7.5 mm

X-axis 8/9 Hz to 35 Hz :2 g

Y-axis 1 Hz to 8/9 Hz: 3.75 mm

Y-axis 8/9 Hz to 35 Hz :1 g

1 sweep cycle in each axis,

Relay energized

Environmental tests

Item Data

Recommended permanent operating temperature -10 °C to +55°C

(Legibility of display may be impaired above

+55 °C /+131 °F)

Storage and transport temperature limit -25°C to +70°C

Permissible humidity 95 % of relative humidity

Chapter 9 Hardware

105

8.2 IED design

Item Data

Case size 4U×19inch

Weight ≤ 10kg

8.3 CE certificate

Item Data

EMC Directive EN 61000-6-2 and EN61000-6-4 (EMC Council

Directive 2004/108/EC)

Low voltage directive EN 60255-27 (Low-voltage directive 2006/95 EC).

Chapter 9 Hardware

106

Chapter 10 Appendix

107

Chapter 10 Appendix

About this chapter

This chapter describes the appendix.

Chapter 10 Appendix

108

1 General setting list

1.1 IED parameter

No Parameter Description Unit Min. Max.

1 Bus Voltage Connected Enable or disable the bus voltage

conenction 0 1

2 CT1 As the B/C Main CT CT1 is set as the main CT of bus

coupler 0 1

3 Isol Fail Block Protec Isolator 1 fail to block the protection 0 1

4 DR_Sample Rate 600 Disturbance recording_sample rate

600 or 1200 0 1

5 BI SetGrp Switch Binary input for setting group switch 0 1

6 Max Bays Maximum bays 2 17

7 VT_Primary:Ph-Ph Primary VT rated voltage:

phase-phase

kV 0 1500

8 VT_Secondary:Ph-Ea Secondary VT rated voltage:

phase-earth

V 0 1000

9 CT_Secondary The setting for secondary side CT A 1 5

10 CT_Ratio: Base CT_Ratio: Base 0 5000

11 CT1_Ratio: Bay1 CT1_Ratio: Bay1 0 5000

12 CT2_Ratio: Bay1 CT2_Ratio: Bay1 0 5000

13 CT_Ratio: Bay2 CT_Ratio: Bay2 0 5000














Chapter 10 Appendix

109




29 Time Pre Fault Recording time for pre-fault s 0.05 0.3

30 Time Post Fault Recording time for post-fault s 1.0 4.5

31 Time Iso confirm Time for isolator status confirmation s 0.05 1.0

32 Time CB confirm Time for CB status confirmation s 0.05 2.0

1.2 Function setting list


33 I_Diff Current setting for busbar differential

protection A 0.1 99.99

34 K_Diff Restraint factor for busbar differential

protection 0.3 0.99

35 I_CTFailAlm:Feeder Current setting for CT failure alarm:

feeder A 0.01 99.99

36 I_CTFailBlk:Feeder Current setting for CT failure blocking:

feeder A 0.01 99.99

37 I_CTFailAlm:B/C Current setting for CT failure alarm:

B/C A 0.01 99.99

38 I_CTFailBlk:B/C Current setting for CT failure blocking:

B/C A 0.01 99.99

39 I_CBF:Bay1 Phase current setting for CBF

protection of bay 1 A 0.05 100.0

40 3I0_CBF:Bay1 Zero sequence current setting for CBF


41 3I2_CBF:Bay1 Negative sequence current setting for


42 T_CBF1:Bay1 Time delay for CBF stage 1 of bay 1 s 0 32.00










Chapter 10 Appendix

110










































Chapter 10 Appendix

111










































Chapter 10 Appendix

112










































Chapter 10 Appendix

113


124 T_DeadZone:Bay1 Time delay of dead zone protection for

bay 1 s 0 32.00


bay 2 s 0 32.00


bay 3 s 0 32.00


bay 4 s 0 32.00


bay 5 s 0 32.00


bay 6 s 0 32.00


bay 7 s 0 32.00


bay 8 s 0 32.00


bay 9 s 0 32.00


bay 10 s 0 32.00


bay 11 s 0 32.00


bay 12 s 0 32.00


bay 13 s 0 32.00


bay 14 s 0 32.00


bay 15 s 0 32.00


bay 16 s 0 32.00


bay 17 s 0 32.00

1.3 Binary setting list

No Setting Description Unit Min. Max.

1 Func_Diff ON Busbar differential protection

enabled or disabled 0 1

2 CT Fail Alarm ON CT fail alarm enabled or disabled 0 1

3 CT Fail Block ON CT fail blocking enabled or disabled 0 1

Chapter 10 Appendix

114


4 Bay1 Func_CBF On CBF protection enabled or disable

for bay 1 0 1

5 Bay1 CBF Chk 3I0/3I2




0 1

6 Bay1 Init from Ext CBF Initiation from external CBF function

for bay 1 0 1


for bay 2 0 1





0 1


for bay 2 0 1


for bay 3 0 1





0 1


for bay 3 0 1


for bay 4 0 1





0 1


for bay 4 0 1


for bay 5 0 1





0 1


for bay 5 0 1


for bay 6 0 1





0 1


for bay 6 0 1

Chapter 10 Appendix

115



for bay 7 0 1





0 1


for bay 7 0 1


for bay 8 0 1





0 1


for bay 8 0 1


for bay 9 0 1





0 1


for bay 9 0 1


for bay 10 0 1





0 1


for bay 10 0 1


for bay 11 0 1





0 1


for bay 11 0 1


for bay 12 0 1





0 1


for bay 12 0 1

Chapter 10 Appendix

116



for bay 13 0 1





0 1


for bay 13 0 1


for bay 14 0 1





0 1


for bay 14 0 1


for bay 15 0 1





0 1


for bay 15 0 1


for bay 16 0 1





0 1


for bay 16 0 1


for bay 17 0 1





0 1


for bay 17 0 1

55 Bay1 Func_Dead Zone On Enable or disable the dead zone

protection for bay 1 0 1







Chapter 10 Appendix

117




























Chapter 10 Appendix

118

2 General report list

Table 42 Event report list

No. Abbr. (LCD Display) Description

1 Diff Startup Differential protection startup

2 BZ1 Diff Tp: PhA Phase A differential protection of Bus zone 1 trip

3 BZ1 Diff Tp: PhB Phase B differential protection of Bus zone 1 trip

4 BZ1 Diff Tp: PhC Phase C differential protection of Bus zone 1 trip

5 BZ2 Diff Tp: PhA Phase A differential protection of Bus zone 2 trip

6 BZ2 Diff Tp: PhB Phase B differential protection of Bus zone 2 trip

7 BZ2 Diff Tp: PhC Phase C differential protection of Bus zone 2 trip

8 BZT Diff Tp: PhA Phase A differential protection of Transfer bus zone trip

9 BZT Diff Tp: PhB Phase B differential protection of Transfer bus zone trip

10 BZT Diff Tp: PhC Phase C differential protection of Transfer bus zone trip

11 CBF Startup CBF protection startup

12 CBF1 Trip CBF protection stage 1 trips

13 BZ1 CBF2 Trip CBF protection stage 2 of bus zone I trips

14 BZ2 CBF2 Trip CBF protection stage 2 of bus zone II trips.

15 BZT CBF2 Trip

CBF protection stage 2 of transfer bus zone issues trip

command

16 CBF Transf.Trip

The IED issues transfer trip command to the remote end of the

feeder or the other windings of transformer.

17 DeadZone Startup Dead zone protection startup

18 DeadZone Trip Dead zone protection trips

19 BI SetGroup Mode Binary input setting group mode

Table 43 Alarm report list


1 AI Err Analogue input error

2 B/C CBF StartErr CBF of bus coupler startup error

3 B/C CT Fail: PhA Phase A of bus coupler CT fail

4 B/C CT Fail: PhB Phase B of bus coupler CT fail

5 B/C CT Fail: PhC Phase C of bus coupler CT fail

6 Battery Off Battery off

7 BI Breakdown Binary input break down

8 BI Check Err Binary input check error

9 BI Comm Fail Binary input communication fail

10 BI Config Err Binary input configuration error

11 BI EEPROM Err Binary input EEPROM error

12 BI Input Err Binary input input error

Chapter 10 Appendix

119


13 BI Module Err Binary input module error

14 BO Breakdown Binary output breakdown

15 BO Comm Fail Binary output communication fail

16 BO Config Err Binary output configuration error

17 BO EEPROM Err Binary output EEPROM error

18 BO Module Err Binary output module error

19 BO No Response Binary output no response

20 Bus Tied Bus Tied

21 BZ1 CT Fail: PhA Phase A of busbar zone 1 CT fail

22 BZ1 CT Fail: PhB Phase B of busbar zone 1 CT fail

23 BZ1 CT Fail: PhC Phase C of busbar zone 1 CT fail

24 BZ1 VT Fail Busbar zone 1 VT fail

25 BZ2 CT Fail: PhA Phase A of busbar zone 2 CT fail

26 BZ2 CT Fail: PhB Phase B of busbar zone 2 CT fail

27 BZ2 CT Fail: PhC Phase C of busbar zone 2 CT fail

28 BZ2 VT Fail Busbar zone 2 VT fail

29 BZT CT Fail: PhA Phase A of transfer busbar zone CT fail

30 BZT CT Fail: PhB Phase B of transfer busbar zone CT fail

31 BZT CT Fail: PhC Phase C of transfer busbar zone CT fail

32 BZT VT Fail Transfer bus VT fail

33 CAN Comm Fail CAN network communication fail

34 CAN Comm Recover CAN network communication recorver

35 CB Discord CB discordance

36 CT Ratio Err CT ratio error

37 CT Secondary Err Secondary side CT error

38 DI Err Binary input error

39 EquipPara Err Equipment parameter error

40 FLASH Check Err Falsh check error

41 Isol DC Failure Isolator DC failure

42 Isol Failure Isolator failure

43 NO/NC Discord NO/NC discordance

44 ROM Verify Err ROM verify error

45 Sample Data Err Sample data error

46 Sampling Err Sampling error

47 SamROM VerifyErr Sample ROM verify error

48 Set Group Err Setting group Error

49 Setting Err Setting error

50 Soft Version Err Software version error

51 SRAM Check Err SRAM check error

52 Start 3-Ph Err Startup three phase error

53 Start A-Ph Err Startup phase A error

Chapter 10 Appendix

120


54 Start B-Ph Err Startup phase B error

55 Start C-Ph Err Startup phase C error

56 SysConfig Err System configuration error

57 TBC CB Discord Transfer bus coupler CB discordance

58 Test BO Un-reset Test binary output unreset

Chapter 10 Appendix

121

3 Typical connection

A. Single busbar with line side CTs arrangement

Busbar-A

CSC-

150

Figure 26 Typical connection diagram A

B. Single busbar with bus side CTs arrangement

Busbar-A

CSC-

150

Figure 27 Typical connection diagram B

Chapter 10 Appendix

122

C. Single busbar with tie disconnector (line side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 28 Typical connection diagram C

D. Single busbar with tie disconnector (bus side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 29 Typical connection diagram D

Chapter 10 Appendix

123

E. Single busbar with tie disconnector and one CT (line side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 30 Typical connection diagram E

F. Two single busbars connected with bus coupler and one CT (line side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 31 Typical connection diagram F

Chapter 10 Appendix

124

G. Two single busbars connected with bus coupler and one CT (bus side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 32 Typical connection diagram G

H. Two single busbars connected with bus coupler and two CTs (line side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 33 Typical connection diagram H

Chapter 10 Appendix

125

I. Two single busbars connected with bus coupler and two CTs (bus side CTs) arrangement

Busbar-A

CSC-

150

Busbar-B

Figure 34 Typical connection diagram I

J. One and half breaker arrangement

Busbar-B

Busbar-A

CSC-

150

Chapter 10 Appendix

126

Figure 35 Typical connection diagram J

Chapter 10 Appendix

127

K. Double busbar with one coupler CT arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 36 Typical connection diagram K

L. Double busbar with two coupler CTs arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 37 Typical connection diagram L

Chapter 10 Appendix

128

M. Main and transfer busbar with two coupler CTs (inside CTs) arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 38 Typical connection diagram M

N. Main and transfer busbar with two coupler CTs (outside CTs) arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 39 Typical connection diagram N

Chapter 10 Appendix

129

O. Main and transfer busbar with one coupler CTs (inside CTs) arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 40 Typical connection diagram O

P. Main and transfer busbar with one coupler CTs (outside CTs) arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 41 Typical connection diagram P

Chapter 10 Appendix

130

Q. Main and transfer busbar without coupler CTs (outside CTs) arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 42 Typical connection diagram Q

R. Main and main and/or transfer busbar with inside CTs arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 43 Typical connection diagram R

Chapter 10 Appendix

131

S. Main and main and/or transfer busbar with outside CTs arrangement

Busbar-A

Busbar-B

CSC-

150

Figure 44 Typical connection diagram S

T. Double main and transfer busbar with inside CTs arrangement

Busbar-A

Busbar-B

Busbar-C

CSC-

150

Figure 45 Typical connection diagram T

Chapter 10 Appendix

132

U. Double main and transfer busbar with outside CTs arrangement

Busbar-A

Busbar-B

Busbar-C

CSC-

150

Figure 46 Typical connection diagram U

4 CT Requirement

4.1 Overview

In practice, the conventional magnetic- core current transformer (hereinafter

as referred CT) is not able to transform the current signal accurately in whole

fault period of all possible faults because of manufactured cost and

installation space limited. CT Saturation will cause distortion of the current

signal and can result in a failure to operate or cause unwanted operations of

some functions. Although more and more protection IEDs have been

designed to permit CT saturation with maintained correct operation, the

performance of protection IED is still depended on the correct selection of CT.

4.2 Current transformer classification

The conventional CTs are usually manufactured in accordance with the

standard, IEC 60044, ANSI / IEEE C57.13, ANSI / IEEE C37.110 or other

comparable standards, which CTs are specified in different protection class.

Currently, the CT for protection are classified according to functional

performance as follows:

Chapter 10 Appendix

133

Class P CT

Accuracy limit defined by composite error with steady symmetric primary

current. No limit for remanent flux.

Class PR CT

CT with limited remanence factor for which, in some cased, a value of the

secondary loop time constant and/or a limiting value of the winding

resistance may also be specified.

Class PX CT

Low leakage reactance for which knowledge of the transformer

secondary excitation characteristic, secondary winding resistance,

secondary burden resistance and turns ratio is sufficient to assess its

performance in relation to the protective relay system with which it is to

be used.

Class TPS CT

Low leakage flux current transient transformer for which performance is

defined by the secondary excitation characteristics and turns ratio error

limits. No limit for remanent flux

Class TPX CT

Accuracy limit defined by peak instantaneous error during specified

transient duty cycle. No limit for remanent flux.

Class TPY CT

Accuracy limit defined by peak instantaneous error during specified

transient duty cycle. Remanent flux not to exceed 10% of the saturation

flux..

Class TPZ CT

Accuracy limit defined by peak instantaneous alternating current

component error during single energization with maximum d.c. offset at

specified secondary loop time constant. No requirements for d.c.

component error limit. Remanent flux to be practically negligible.

TPE class CT (TPE represents transient protection and electronic type

CT)

4.3 Abbreviations (according to IEC 60044-1, -6, as defined)

Abbrev. Description

Esl Rated secondary limiting e.m.f

Chapter 10 Appendix

134

Eal Rated equivalent limiting secondary e.m.f

Ek Rated knee point e.m.f

Uk Knee point voltage (r.m.s.)

Kalf Accuracy limit factor

Kssc Rated symmetrical short-circuit current factor

K’ssc

K”ssc

Effective symmetrical short-circuit current factor

based on different Ipcf

Kpcf Protective checking factor

Ks Specified transient factor

Kx Dimensioning factor

Ktd Transient dimensioning factor

Ipn Rated primary current

Isn Rated secondary current

Ipsc Rated primary short-circuit current

Ipcf protective checking current

Isscmax Maximum symmetrical short-circuit current

Rct Secondary winding d.c. resistance at 75 °C /

167 °F (or other specified temperature)

Rb Rated resistive burden

R’b = Rlead + Rrelay = actual connected resistive

burden

Rs Total resistance of the secondary circuit,

inclusive of the secondary winding resistance

corrected to 75℃, unless otherwise specified,

and inclusive of all external burden connected.

Rlead Wire loop resistance

Zbn Rated relay burden

Zb Actual relay burden

Tp Specified primary time constant

Ts Secondary loop time constant

4.4 General current transformer requirements

4.4.1 Protective checking current

The current error of CT should be within the accuracy limit required at

specified fault current.

To verify the CT accuracy performance, Ipcf, primary protective checking

current, should be chose properly and carefully.

For different protections, Ipcf is the selected fault current in proper fault

position of the corresponding fault, which will flow through the verified CT.

Chapter 10 Appendix

135

To guarantee the reliability of protection relay, Ipcf should be the maximum

fault current at internal fault. E.g. maximum primary three phase short-circuit

fault current or single phase earth fault current depended on system

sequence impedance, in different positions.

Moreover, to guarantee the security of protection relay, Ipcf should be the

maximum fault current at external fault.

Last but not least, Ipcf calculation should be based on the future possible

system power capacity

Kpcf, protective checking factor, is always used to verified the CT

performance

To reduce the influence of transient state, Kalf, Accuracy limit factor of CT,

should be larger than the following requirement

Ks, Specified transient factor, should be decided based on actual operation

state and operation experiences by user.

4.4.2 CT class

The selected CT should guarantee that the error is within the required

accuracy limit at steady symmetric short circuit current. The influence of short

circuit current DC component and remanence should be considered, based

on extent of system transient influence, protection function characteristic,

consequence of transient saturation and actual operating experience. To fulfill

the requirement on a specified time to saturation, the rated equivalent

secondary e.m.f of CTs must higher than the required maximum equivalent

secondary e.m.f that is calculated based on actual application.

For the CTs applied to transmission line protection, transformer differential

protection with 330kV voltage level and above, and 300MW and above

generator-transformer set differential protection, the power system time

constant is so large that the CT is easy to saturate severely due to system

transient state. To prevent the CT from saturation at actual duty cycle, TP

class CT is preferred.

Chapter 10 Appendix

136

For TPS class CT, Eal (rated equivalent secondary limiting e.m.f) is generally

determined as follows:

Where

Ks: Specified transient factor

Kssc: Rated symmetrical short-circuit current factor

For TPX, TPY and TPZ class CT, Eal (rated equivalent secondary limiting

e.m.f) is generally determined as follows:

Where

Ktd: Rated transient dimensioning factor

Considering at short circuit current with 100% offset

For C-t-O duty cycle,

t: duration of one duty cycle;

For C-t’-O-tfr-C-t”-O duty cycle,

t’: duration of first duty cycle;

t”: duration of second duty cycle;

tfr: duration between two duty cycle;

For the CTs applied to 110 - 220kV voltage level transmission line protection,

110 - 220kV voltage level transformer differential protection, 100-200MW

generator-transformer set differential protection, and large capacity motor

differential protection, the influence of system transient state to CT is so less

that the CT selection is based on system steady fault state mainly, and leave

proper margin to tolerate the negative effect of possible transient state.

Therefore, P, PR, PX class CT can be always applied.

For P class and PR class CT, Esl (the rated secondary limited e.m.f) is

generally determined as follows:

Kalf: Accuracy limit factor

Chapter 10 Appendix

137

For PX class CT, Ek (rated knee point e.m.f) is generally determined as

follows:

Kx: Demensioning factor

For the CTs applied to protection for110kV voltage level and below system,

the CT should be selected based on system steady fault state condition. P

class CT is always applied.

4.4.3 Accuracy class

The CT accuracy class should guarantee that the protection relay applied is

able to operate correctly even at a very sensitive setting, e.g. for a sensitive

residual overcurrent protection. Generally, the current transformer should

have an accuracy class, which have an current error at rated primary current,

that is less than ±1% (e.g. class 5P).

If current transformers with less accuracy are used it is advisable to check the

actual unwanted residual current during the commissioning.

4.4.4 Ratio of CT

The current transformer ratio is mainly selected based on power system data

like e.g. maximum load. However, it should be verified that the current to the

protection is higher than the minimum operating value for all faults that are to

be detected with the selected CT ratio. The minimum operating current is

different for different functions and settable normally. So each function should

be checked separately.

4.4.5 Rated secondary current

There are 2 standard rated secondary currents, 1A or 5A. Generally, 1 A

should be preferred, particularly in HV and EHV stations, to reduce the

burden of the CT secondary circuit. Because 5A rated CTs, i.e. I2R is 25x

compared to only 1x for a 1A CT. However, in some cases to reduce the CT

secondary circuit open voltage, 5A can be applied.

4.4.6 Secondary burden

Too high flux will result in CT saturation. The secondary e.m.f is directly

proportional to linked flux. To feed rated secondary current, CT need to

Chapter 10 Appendix

138

generate enough secondary e.m.f to feed the secondary burden.

Consequently, Higher secondary burden, need Higher secondary e.m.f, and

then closer to saturation. So the actual secondary burden R’b must be less

than the rated secondary burden Rb of applied CT, presented

Rb > R’b

The CT actual secondary burden R’b consists of wiring loop resistance Rlead

and the actual relay burdens Zb in whole secondary circuit, which is

calculated by following equation

R’b = Rlead + Zb

The rated relay burden, Zbn, is calculated as below:

Where

Sr: the burden of IED current input channel per phase, in VA;

For earth faults, the loop includes both phase and neutral wire, normally twice

the resistance of the single secondary wire. For three-phase faults the neutral

current is zero and it is just necessary to consider the resistance up to the

point where the phase wires are connected to the common neutral wire. The

most common practice is to use four wires secondary cables so it normally is

sufficient to consider just a single secondary wire for the three-phase case.

In isolated or high impedance earthed systems the phase-to-earth fault is not

the considered dimensioning case and therefore the resistance of the single

secondary wire always can be used in the calculation, for this case.

4.5 Rated equivalent secondary e.m.f requirements

To guarantee correct operation, the current transformers (CTs) must be able

to correctly reproduce the current for a minimum time before the CT will begin

to saturate.

4.5.1 Busbar differential protection

The busbar differential protection is able to detect CT saturation in extremely

short time and then block protection at external fault. The protection can

discriminate the internal or external fault in 2-3 ms before CT saturation. So

the currents from different class CT of different feeders are permitted to inject

into the protection relay. The rated secondary e.m.f of CTs is verified by

maximum symmetric short circuit current at external fault.

For P Class, PR class CT,

Chapter 10 Appendix

139

For TP class CT,

Ipcf: Maximum primary short circuit current at external faults (A)

csc-150 busbar protection ied technical application manual_v1.01

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