Toshiba GRL100-701B User manual

6F2S0850
INSTRUCTION MANUAL
LINE DIFFERENTIAL RELAY
GRL100 - 7∗∗B
©TOSHIBA Corporation 2006
All Rights Reserved.
( Ver. 0.3 )
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Safety Precautions
Before using this product, please read this chapter carefully.
This chapter describes the safety precautions recommended when using the GRL100. Before
installing and using the equipment, this chapter must be thoroughly read and understood.
Explanation of symbols used
Signal words such as DANGER, WARNING, and two kinds of CAUTION, will be followed by
important safety information that must be carefully reviewed.
Indicates an imminently hazardous situation which will result in death or
serious injury if you do not follow the instructions.
Indicates a potentially hazardous situation which could result in death or
serious injury if you do not follow the instructions.
CAUTION Indicates a potentially hazardous situation which if not avoided, may result
in minor injury or moderate injury.
CAUTION Indicates a potentially hazardous situation which if not avoided, may result
in property damage.
DANGE
R
WARNING
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•Current transformer circuit
Never allow the current transformer (CT) secondary circuit connected to this equipment to be
opened while the primary system is live. Opening the CT circuit will produce a dangerously high
voltage.
•Exposed terminals
Do not touch the terminals of this equipment while the power is on, as the high voltage generated
is dangerous.
•Residual voltage
Hazardous voltage can be present in the DC circuit just after switching off the DC power supply.
It takes approximately 30 seconds for the voltage to discharge.
•Fiber optic
Invisible laser radiation
Do not view directly with optical instruments.
Class 1M laser product (Transmission distance: 30km class)
- the maximum output of laser radiation: 0.2 mW
- the pulse duration: 79.2 ns
- the emitted wavelength(s): 1310 nm
CAUTION
•Earth
The earthing terminal of the equipment must be securely earthed.
CAUTION
•Operating environment
The equipment must only used within the range of ambient temperature, humidity and dust
detailed in the specification and in an environment free of abnormal vibration.
•Ratings
Before applying AC voltage and current or the DC power supply to the equipment, check that
they conform to the equipment ratings.
•Printed circuit board
Do not attach and remove printed circuit boards when the DC power to the equipment is on, as
this may cause the equipment to malfunction.
•External circuit
When connecting the output contacts of the equipment to an external circuit, carefully check the
supply voltage used in order to prevent the connected circuit from overheating.
•Connection cable
Carefully handle the connection cable without applying excessive force.
DANGE
R
WARNING
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•Modification
Do not modify this equipment, as this may cause the equipment to malfunction.
•Short-link
Do not remove a short-link which is mounted at the terminal block on the rear of the relay before
shipment, as this may cause the performance of this equipment such as withstand voltage, etc., to
reduce.
•Disposal
When disposing of this equipment, do so in a safe manner according to local regulations.
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Contents
Safety Precautions 1
1. Introduction 9
2. Application Notes 11
2.1 Protection Schemes 11
2.2 Current Differential Protection 12
2.2.1 Operation of Current Differential Protection 12
2.2.2 Segregated-phase Current Differential Protection 12
2.2.3 Zero-phase Current Differential Protection 13
2.2.4 Fail-safe Function 14
2.2.5 Remote Differential Trip 15
2.2.6 Transmission Data 17
2.2.7 Synchronized Sampling 17
2.2.8 Charging Current Compensation 24
2.2.9 Blind Zone Protection 25
2.2.10 Application to Three-terminal Lines 26
2.2.11 Dual Communication Mode 28
2.2.12 Application to One-and-a-half Breaker Busbar System 28
2.2.13 Communication System 29
2.2.14 Setting 35
2.3 Distance Protection 43
2.3.1 Time-Stepped Distance Protection 43
2.3.2 Command Protection 58
2.3.3 Power Swing Blocking 73
2.4 Directional Earth Fault Protection 76
2.4.1 Directional Earth Fault Command Protection 77
2.4.2 Directional Earth Fault Protection 81
2.5 Overcurrent Backup Protection 83
2.5.1 Inverse Time Overcurrent Protection 84
2.5.2 Definite Time Overcurrent Protection 86
2.6 Transfer Trip Function 87
2.7 Out-of-step Protection 88
2.8 Thermal Overload Protection 90
2.9 Overvoltage and Undervoltage Protection 93
2.9.1 Overvoltage Protection 93
2.9.2 Undervoltage Protection 97
2.10 Broken Conductor Protection 101
2.11 Breaker Failure Protection 104
2.12 Switch-Onto-Fault Protection 107
2.13 Stub Protection 109
2.13.1 STUB DIF Protection 109
2.13.2 STUB OC Protection 109
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2.13.3 Setting 110
2.14 Tripping Output 111
2.15 Autoreclose 113
2.15.1 Application 113
2.15.2 Scheme Logic 115
2.15.3 Autoreclose Output Signals 131
2.16 Characteristics of Measuring Elements 132
2.16.1 Segregated-phase Current Differential Element DIF and DIFSV 132
2.16.2 Zero-phase Current Differential Element DIFG 133
2.16.3 Distance Measuring Elements Z1, Z2, Z3, Z4, ZR and PSB 134
2.16.4 Phase Selection Element UVC 142
2.16.5 Directional Earth Fault Elements DEFF and DEFR 143
2.16.6 Inverse Definite Minimum Time (IDMT) Overcurrent Element OCI and
EFI 144
2.16.7 Thermal Overload Element 145
2.16.8 Out-of-Step Element OST 145
2.16.9 Voltage and Synchronism Check Elements OVL, UVL, OVB, UVB and
SYN 146
2.16.10 Current change detection elements OCD, OCD1 and EFD 147
2.16.11 Level Detectors 147
2.17 Fault Locator 149
2.17.1 Application 149
2.17.2 Starting Calculation 149
2.17.3 Displaying Location 149
2.17.4 Distance to Fault Calculation 150
2.17.5 Setting 154
3. Technical Description 158
3.1 Hardware Description 158
3.1.1 Outline of Hardware Modules 158
3.1.2 Transformer Module 161
3.1.3 Signal Processing and Communication Module 162
3.1.4 Binary Input and Output Module 163
3.1.5 Human Machine Interface (HMI) Module 167
3.2 Input and Output Signals 169
3.2.1 Input Signals 169
3.2.2 Binary Output Signals 172
3.2.3 PLC (Programmable Logic Controller) Function 172
3.3 Automatic Supervision 173
3.3.1 Basic Concept of Supervision 173
3.3.2 Relay Monitoring 173
3.3.3 CT Circuit Current Monitoring 174
3.3.4 CT Circuit Failure Detection 175
3.3.5 Voltage Transformer Failure Supervision 175
3.3.6 Differential Current (Id) Monitoring 177
3.3.7 Telecommunication Channel Monitoring 178
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3.3.8 GPS Signal Reception Monitoring (For GPS-mode only) 178
3.3.9 Relay Address Monitoring 178
3.3.10 Disconnector Monitoring 178
3.3.11 Failure Alarms 179
3.3.12 Trip Blocking 180
3.3.13 Setting 180
3.4 Recording Function 181
3.4.1 Fault Recording 181
3.4.2 Event Recording 182
3.4.3 Disturbance Recording 182
3.5 Metering Function 184
4. User Interface 185
4.1 Outline of User Interface 185
4.1.1 Front Panel 185
4.1.2 Communication Ports 187
4.2 Operation of the User Interface 189
4.2.1 LCD and LED Displays 189
4.2.2 Relay Menu 192
4.2.3 Displaying Records 194
4.2.4 Displaying the Status 198
4.2.5 Viewing the Settings 204
4.2.6 Changing the Settings 205
4.2.7 Testing 225
4.3 Personal Computer Interface 232
4.4 Relay Setting and Monitoring System 232
4.5 IEC 60870-5-103 Interface 233
4.6 Clock Function 233
5. Installation 234
5.1 Receipt of Relays 234
5.2 Relay Mounting 234
5.3 Electrostatic Discharge 234
5.4 Handling Precautions 234
5.5 External Connections 235
6. Commissioning and Maintenance 237
6.1 Outline of Commissioning Tests 237
6.2 Cautions 238
6.2.1 Safety Precautions 238
6.2.2 Cautions on Tests 238
6.3 Preparations 239
6.4 Hardware Tests 240
6.4.1 User Interfaces 240
6.4.2 Binary Input Circuit 241
6.4.3 Binary Output Circuit 242
6.4.4 AC Input Circuits 243
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6.5 Function Test 244
6.5.1 Measuring Element 244
6.5.2 Timer 269
6.5.3 Protection Scheme 271
6.5.4 Metering and Recording 275
6.5.5 Fault Locator 275
6.6 Conjunctive Tests 277
6.6.1 On Load Test 277
6.6.2 Signaling Circuit Test 277
6.6.3 Tripping and Reclosing Circuit Test 279
6.7 Maintenance 281
6.7.1 Regular Testing 281
6.7.2 Failure Tracing and Repair 281
6.7.3 Replacing Failed Modules 283
6.7.4 Resumption of Service 285
6.7.5 Storage 285
7. Putting Relay into Service 286
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Appendix A Block Diagram 287
Appendix B Signal List 289
Appendix C Variable Timer List 323
Appendix D Binary Output Default Setting List 325
Appendix E Details of Relay Menu and LCD & Button Operation 329
Appendix F Case Outline 339
Appendix G Typical External Connection 347
Appendix H Relay Setting Sheet 351
Appendix I Commissioning Test Sheet (sample) 381
Appendix J Return Repair Form 387
Appendix K Technical Data 393
Appendix L Symbols Used in Scheme Logic 409
Appendix MMulti-phase Autoreclose 413
Appendix N Data Transmission Format 417
Appendix O Example of Setting 423
Appendix P Programmable Reset Characteristics and Implementation of Thermal
Model to IEC60255-8 435
Appendix Q IEC60870-5-103: interoperability 439
Appendix R Inverse Time Characteristics 453
Appendix S Failed Module Tracing and Replacement 457
Appendix S PLC Setting Sample 463
Appendix T Ordering 467
The data given in this manual are subject to change without notice. (Ver.0.3)
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1. Introduction
The GRL100 provides high-speed phase-segregated current differential protection for use with
telecommunication systems, and ensures high reliability and security for diverse faults including
single-phase and multi-phase faults and double-faults on double-circuit lines, evolving faults
and high-impedance earth faults.
The GRL100 is used as a main protection for the following two- or three-terminal lines in EHV
or HV networks:
•Overhead lines or underground cables
•Lines with weak infeed or non-infeed terminals
•Single or parallel lines
•Lines with heavy load current
•Short- or long-distance lines
The GRL100 actuates high-speed single-shot autoreclose or multi-shot autoreclose.
The GRL100 can be used for lines associated with one-and-a-half busbar arrangement as well as
single or double busbar arrangement.
For telecommunications using the current differential protection, dedicated optical fibres or 64
kbits/s multiplexed communication links can be employed.
Furthermore, in addition to current differential protection, the GRL100 provides distance, directional
earth fault, overcurrent backup, thermal overload, under- and over-voltage, out-of-step and breaker
failure protection.
The GRL100 is a member of the G-series family of numerical relays which utilise common
hardware modules with the common features:
The GRL100 provides the following metering and recording functions.
- Metering
- Fault record
- Event record
- Fault location
- Disturbance record
The GRL100 provides the following menu-driven human interfaces for relay setting or viewing
of stored data.
- Relay front panel; 4 ×40 character LCD, LED display and keypad
- Local PC
- Remote PC
Password protection is provided to change settings. Eight active setting groups are provided.
This allows the user to set one group for normal operating conditions while other groups may be
set to cover alternative operating conditions.
GRL100 provides either two or three serial ports, and an IRIG-B port for an external clock
connection. A local PC can be connected via the RS232C port on the front panel of the relay.
Either one or two rear ports (RS485 or fibre optic) are provided for connection to a remote PC
and for IEC60870-5-103 communication with a substation control and automation system.
Further, the GRL100 provides the following functions.
- Configurable binary inputs and outputs
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- Programmable logic for I/O configuration, alarms, indications, recording, etc.
- Automatic supervision
The GRL100 has the following models:
Relay Type and Model
Relay Type:
- Type GRL100; Numerical current differential relay
Relay Model:
- For two terminal line, With distance protection and autoreclose
•Model 701; 25 binary inputs, 19 binary outputs, 6 binary outputs for tripping
•Model 702; 28 binary inputs, 37 binary outputs, 6 binary outputs for tripping
- For three terminal line, With distance protection and autoreclose
•Model 711; 25 binary inputs, 19 binary outputs, 6 binary outputs for tripping
•Model 712; 28 binary inputs, 37 binary outputs, 6 binary outputs for tripping
Table 1.1 GRL100 Models
Model 701B 702B 711B 712B
2- or 3-terminal line application 2-terminal 2-terminal 3-terminal 3-termnal
Segregated-phase current differential protection (DIF) x x x x
Zero-phase current differential protection (DIFG) x x x x
Charging current compensation (CCC) x x x x
Distance protection (DZ) x x x x
Power swing blocking (PSB) x x x x
Directional earth fault protection (DEF) x x x x
Switch-on-to-fault protection (SOTF) x x x x
Stub protection (STUB) x x x x
Phase overcurrent protection (OC) x x x x
Earth fault overcurrent protection (EF) x x x x
Thermal overload protection (THM) x x x x
Undervoltage protection (UV) x x x x
Overvoltage protection (OV) x x x x
Broken conductor detection (BCD) x x x x
Breaker failure protection (BF) x x x x
Out-of-step protection (OST) x x x x
Autoreclose (ARC) x x x x
Fault location (FL) x x x x
CT failure detection (CTF) x x x x
VT failure detection (VTF) x x x x
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2. Application Notes
2.1 Protection Schemes
The GRL100 provides the following protection schemes (Appendix A shows block diagrams of the
GRL100-700 series):
•Segregated-phase current differential protection
•Zero-phase current differential protection
•Three-stepped distance protection and command protection
•Directional earth fault protection
•SOTF and Stub protection
•Overcurrent backup protection
•Thermal overload protection
•Overvoltage and undervoltage protection
•Broken conductor detection
•Out-of-step protection
•Breaker failure protection
•Transfer trip protection
Zero-phase current differential protection enables sensitive protection for high-impedance earth
faults.
Overcurrent backup protection provides both inverse time overcurrent and definite time
overcurrent protection for phase faults and earth faults.
Out-of-step protection performs phase comparison of the local and remote voltages and operates
only when the out-of-step loci cross the protected line.
Furthermore, the GRL100 incorporates autoreclose functions, charging current compensation
for cable or long-distance lines and fault location. The autoreclose mode can be selected from
single-phase, three-phase, single- and three-phase and multi-phase modes.
The current differential protection utilises with the microwave or fibre optic digital
telecommunication systems to transmit instantaneous current values sampled synchronously at
each terminal.
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2.2 Current Differential Protection
GRL100 is applicable to telecommunication systems which employ dedicated optical fibre, 64 kbit/s
multiplexed communication channels or microwave links.
2.2.1 Operation of Current Differential Protection
Current differential protection compares the currents flowing into and out of the protected line.
The difference of the currents, that is, the differential current, is almost zero when a fault is
external or there is no fault, and is equal to the fault current when the fault is internal. The
differential protection operates when the difference of the currents exceeds a set value.
The GRL100 relay installed at each line terminal samples the local currents every 7.5 electrical
degrees and transmits the current data to other terminals every four samples via the
telecommunication system. The GRL100 performs master/master type current differential
protection using the current data from all terminals.
As synchronized sampling of all terminals is performed in the GRL100, the current data are the
instantaneous values sampled simultaneously at each terminal. Therefore, the differential current
can be easily calculated by summing the local and remote current data with the identical
sampling address. Thus, compensation of transmission delay time is not required.
The GRL100 utilises the individual three phase currents and residual current to perform
segregated-phase and zero-phase current differential protection.
2.2.2 Segregated-phase Current Differential Protection
The segregated-phase differential protection transmits the three phase currents to the remote
terminal, calculates the individual differential currents and detects both phase-to-phase and
phase-to-earth faults on a per phase basis.
Figure 2.2.2.1 shows the scheme logic of the segregated-phase current differential protection.
Output signals of differential elements DIF-A, -B and -C can perform instantaneous tripping of
the breaker on a per phase basis and start the incorporated autoreclose function.
Note: For the symbols used in the scheme logic, see Appendix L.
DIF.FS-A_TP
DIF.FS-B_TP
DIF.FS-C_TP
DIF-A
&
41
& 82: DIF-A_TRIP
&
401
DIF-B
&
42
& 83: DIF-B_TRIP
&
DIF-C
&
Communication
failure, etc.
43
&
1
CRT_BLOCK
1544
84: DIF-C_TRIP
&
DIF-A_FS
1616
DIF-B_FS
1617
DIF-C_FS
1618
403
402
≥1 400
DIF.FS_TRIP
43C ON
&
TELEPROTECTION OFF
(
from IEC103 command
)
DIFFS
1
DIF_BLOCK
1585 DIF BLOCK
Figure 2.2.2.1 Scheme Logic of Segregated-phase Current Differential Protection
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Tripping output signals can be blocked by the PLC command DIF_BLOCK and CRT_BLOCK.
The output signals of DIF-A, DIF-B and DIF-C are also blocked when a communication circuit
failure is detected by the data error check, sampling synchronism check or interruption of the
receive signals. For DIF-A_FS, DIF-B_FS and DIF-C_FS signals, see Section 2.2.4.
The differential elements DIF have a percentage restraining characteristic with weak restraint in
the small current region and strong restraint in the large current region, to cope with CT
saturation. (For details of the characteristic, see Section 2.16.)
Erroneous current data may be transmitted from the remote terminal when the remote relay is
out-of-service for testing or other purposes. To prevent false operation in this case, the relay sets
the receiving current data to zero in the differential current calculation upon detecting that the
remote terminal is out-of-service.
If the relay is applied to a three-terminal line, the zero setting is performed only for the current
data received from an out-of-service terminal.
Figure 2.2.2.2 shows the remote terminal out-of-service detection logic. The local terminal
detects that the remote terminal is out-of-service by receiving a signal LOCAL TEST which is
transmitted when the scheme switch [L. TEST] is set to "ON" at the terminal under test. As an
alternative means, the local terminal can detect it by using the circuit breaker and disconnector
status signal CBDS-A, B and C transmitted from the remote out-of-service terminal. The signal
CBDS-A is "1" when both the circuit breaker and disconnector are closed. Thus, out-of-service
is detected when either the circuit breaker or disconnector is open in all three phases.
Zero setting of the receive current data is also performed at the terminal under test. If the scheme
switch [L. TEST] is set to "ON" or the signal R.DATA_ZERO is input by PLC, all the receive
current data transmitted from the in-service terminal is set to zero and this facilitates the local
testing. The zero setting of the receive current data is not performed by the alternative way as
mentioned above.
The out-of-service detection logic can be blocked by the scheme switch [OTD].
REM1_IN_SRV: Remote 1 in-service
REM1_OFF_SRV: Remote 1 out-of-service
REM1_NON_USE: Remote 1 not used
1
≥1 REM1_OFF_SRV
LOCAL_TEST1
CBDS-A
CBDS-B
CBDS-C
[OTD]
"ON"
(+)
&
[Open1]
"ON"
(+)
1
≥11 REM1_NON_USE
REM1_IN_SRV
207
208
209
≥1
R.DATD_ZERO
1623
≥1
(∗) Out-of-service detection logic for the remote 2 is same as above.
Figure 2.2.2.2 Out-of-Service Detection Logic
Note: When a communication circuit is disconnected or communication circuit failure occurs, do
not close the circuit breaker. When closing it, make sure that the DIF element is blocked.
(Otherwise, it may cause malfunction.)
2.2.3 Zero-phase Current Differential Protection
The GRL100 provides sensitive protection for high-impedance earth faults by employing
zero-phase current differential protection. For more sensitive protection, residual current is
introduced through an auxiliary CT in the residual circuit instead of deriving the zero-phase
current from the three phase currents.
The zero-phase current differential element has a percentage restraining characteristic with weak
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restraint. For details of the characteristic, see Section 2.16.
The scheme logic is shown in Figure 2.2.3.1. The output signal of the differential element DIFG
performs time-delayed three-phase tripping of the circuit breaker with the tripping output signal
DIFG.FS_TRIP. DIFG.FS_TRIP can start the incorporated autoreclose function when the
scheme switch [ARC-DIFG] is set to "ON". The DIFG can trip instantaneously by PLC
command DIFG_INST_TP.
Tripping output signal can be blocked by the PLC command DIFG_BLOCK and CRT_BLOCK.
The output signal is also blocked when a communication circuit failure is detected by data error
check, sampling synchronism check or interruption of the receive signals. For DIFG_FS signal,
see Section 2.2.4.
Since the DIFG is used for high-impedance earth fault protection, the DIFG output signal is
blocked when zero-phase current is large as shown in the following equation:
ΣI01≥2 pu or ΣI02≥2 pu
where,
ΣI01: Scalar summation of zero-phase current at local terminal relay
ΣI02: Scalar summation of zero-phase current at remote terminal relay
pu: per unit value
In GPS-mode setting and backup mode (refer to 2.2.7.2), DIFG is blocked.
DIFG
DIFG.FS_TRIP
"ON"
&
1
Σ

I01

≥2PU
Σ

I02

≥2PU
≥1
Communication failure, etc.
1
DIFG_BLOCK
1586
85
44
DIFG_FS
1619
&
404
43C ON
86
DIFG_TRIP
DIFGFS
DIFG_INST_TP
1632
≥1
&
+
[DIFG]
t 0
TDIFG
0.0-10.0s
&
Figure 2.2.3.1 Scheme Logic of Zero-phase Current Differential Protection
2.2.4 Fail-safe Function
GRL100 provides OC1, OCD and EFD elements. These are used for fail-safe to prevent
unnecessary operation caused by error data in communication failure. OC1 is phase overcurrent
element and its sensitivity can be set. OCD is phase current change detection element, and EFD
is zero-sequence current change detection element. Both of the OCD and EFD sensitivities are
fixed. The scheme logic is shown in Figure 2.2.4.1.
The outputs of DIF.FS_OP and DIFG.FS_OP signals are connected to DIF-A_FS, DIF-B_FS,
DIF-C_FS and DIFG_FS respectively by PLC function. These are connected at the default
setting.
The fail-safe functions are disabled by [DIF-FS] and [DIFG-FS] switches. In the [DIF-FS], OC1
or OCD or both elements can be selected. If these switches are set to “OFF”, the signals of
DIF.FS_OP and DIFG.FS_OP are “1” and the fail-safe is disabled.
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DIF.FS-A_OP
OC1-A
OC1-B
OC1-C
OCD-A
OCD-B
OCD-C
[DIF-FS]
"BOTH"
"OCD"
"OFF"
"OC"
+
&
&
&
&
≥1
≥1
&
&
≥1
≥1
≥1
409
DIF.FS-B_OP
410
DIF.FS-C_OP
411
DIF.FS_OP
408
EFD & ≥1DIFG.FS_OP
412
[DIFG-FS]
"ON"
+
"OFF"
DIFG_FS
(see Fig. 2.2.3.1.)
DIF-A_FS
DIF-B_FS
DIF-C_FS
(see Fig. 2.2.2.1.)
≥1
Figure 2.2.4.1 Fail-safe Logic
2.2.5 Remote Differential Trip
Note: This function is available only when the three-terminal protection is applied by
setting the scheme switch [TERM] to “3-TERM”. In the case of A-MODE setting,
this function is not available.
When one of the telecommunication channels fails, the terminal using the failed channel is
disabled from performing current differential protection, as a result of the failure being detected
through by the telecommunication channel monitoring.
Figure 2.2.5.1 Protection Disabled Terminal with Channel Failure
The remote differential trip (RDIF) function enables the disabled terminal to trip by receiving a
trip command from the sound terminal, which continues to perform current differential
protection.
Figure 2.2.5.2(a) and (b) show the RDIF scheme logic at RDIF command sending terminal (=
sound terminal) and command receiving terminal (= disabled terminal). The sound terminal
GRL100
GRL100
GRL100
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sends the command when the tripping signals RDIF-A-S, RDIF-B-S, RDIF-C-S or RDIF-S are
output locally and the scheme switches [RDIF] and [TERM] are set to “ON” and “3-TERM”
respectively. The RDIF command is sent to the remote terminal via the 64kb/s digital link
together with other data and signals.
The receiving terminal outputs a local three-phase trip signal RDIF-TRIP under the conditions
that when the command RDIF1 or RDIF2 is received from either of the remote terminals, local
differential protection does not operate, the scheme switches [RDIF] and [TERM] are set to
“ON” and “3-TERM” respectively and no communication channel failure exists in the channel
which received the RDIF command.
When the RDIF function is applied, the command sending signals and receiving signals must be
assigned by PLC function.
DIF-A_TRIP
[RDIF]
+ “ON”
&
&
&
DIF-B_TRIP
DIF-C_TRIP
451
≥1
≥1
≥1
452
DIF-G_TRIP &
453
RDIF-A-S
RDIF-B-S
RDIF-C-S
≥1RDIF-S
454
(a) Sending terminal
RD.FS-A TP
456
&
455
457
458
≥1
≥1
≥1
RDIF-A-R1
1684
RDIF-B-R1
1685
RDIF-C-R1
1686
≥1
1
RDIF_BLOCK
1598
RDIF-R1
1687
&
&
&
&
&
&
RDIF_3PTP
1649
≥1
≥1
≥1
RD.FS-B TP
RD.FS-C TP
RD.FS_TRIP
RD.FS-A_ TRIP
Receiving
signal from
Remote
Terminal 1
≥1
≥1
≥1
≥1
≥1
≥1
RDIF-A-R2
1716
RDIF-B-R2
1717
RDIF-C-R2
1718
RDIF-R2
1719
Receiving
signal from
Remote
Terminal 2
43C ON
+ “ON”
[RDIF]
[TERM]
+ “3-TERM”
&
RD.FS-B_ TRIP
RD.FS-C_ TRIP
RDIF-A_FS
1624
RDIF-B_FS
1625
RDIF-C_FS
1626
DIF elements not operated
DIF.FS_OP
(b) Receiving Terminal
Figure 2.2.5.2 Remote Differential Trip
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2.2.6 Transmission Data
The following data are transmitted to the remote terminal via the 64kb/s digital link. The data
depends on the communication mode and whether a function is used or not. The details are
shown in Appendix N.
A-phase current
B-phase current
C-phase current
Residual current
Positive sequence voltage
A-phase differential element output signal
B-phase differential element output signal
C-phase differential element output signal
A-phase breaker and disconnector status
B-phase breaker and disconnector status
C-phase breaker and disconnector status
Scheme switch [LOCAL TEST] status
Scheme switch [TFC] status
Reclose block command
Sampling synchronization control signal
Synchronized test trigger signal
User configurable data
Current and voltage data are instantaneous values which are sampled every 30 electrical degrees
(12 times per cycle) and consist of eleven data bits and one sign bit. This data is transmitted
every sample to the remote terminal.
Three differential element outputs and the transfer trip command are related to remote terminal
tripping and are transmitted every sampling interval.
Other data is transmitted once every power cycle.
The data transmission format and user configurable data are also shown in Appendix N.
A synchronized test trigger signal is used to test the differential protection simultaneously at all
terminals. For details, see Section 6.5.3.
In addition to the above data, cyclic redundancy check bits and fixed check bits are transmitted to
monitor the communication channel. If a channel failure is detected at the local terminal, all the
local and remote current and voltage data at that instant are set to zero and outputs of the
differential protection and out-of-step protection are blocked, and these protections of remote
terminal are also blocked because the channel failure is also detected at the remote terminal.
2.2.7 Synchronized Sampling
The GRL100 performs synchronized simultaneous sampling at all terminals of the protected
line. Two methods are applied for the sampling synchronization; intra-system synchronization
and GPS-based synchronization. The former is applied to communication modes A-MODE and
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B-MODE, and the latter is applied to GPS-MODE.
The intra-system synchronization keeps the sampling timing error between the terminals within
±10µs or ±20µs and the GPS-based system keeps it within ±5µs or ±10µs for two- or
three-terminal applications.
In both methods, the sampling synchronization is realized through timing synchronization
control and sampling address synchronization control. These controls are performed once every
two power cycles.
2.2.7.1 Intra-system Synchronized Sampling for A-MODE and B-MODE
The synchronized sampling is realized using sampling synchronization control signals
transmitted to other terminals together with the power system data. This synchronized sampling
requires neither an external reference clock nor synchronization of the internal clocks of the
relays at different terminals. The transmission delay of the channel is corrected automatically.
Timing synchronization
One of the terminals is selected as the time reference terminal and set as the master terminal. The
other terminal is set as the slave terminal. The scheme switch [SP.SYN] is used for the settings.
Note: The master and slave terminals are set only for the convenience of the sampling timing
synchronization. The GRL100s at all terminals perform identical protection functions and
operate simultaneously.
To perform timing synchronization for the slave terminal, the sampling time difference between
master and slave terminals is measured. The measurement principle of the sampling time
difference ∆T is indicated in Figure 2.2.7.1. The master terminal and slave terminal perform
their own sampling and send a signal that becomes the timing reference for the other terminal.
t
t
Master
terminal
TM
∆T
Slave
terminal
Td2
Td1
Sampling
timing
TF
Figure 2.2.7.1 Timing Synchronization
Each terminal measures the time TMand TFfrom its own sampling instant to the arrival of the
signal from the other terminal. As is evident from the figure, the times TMand TFcan be
obtained by equation (1) and (2) where Td1 and Td2 are the transmission delay of the channel in
each direction. The sampling time difference ∆T can be obtained from the resulting equation (3).
TM= Td1 −∆T (1)
TF= Td2 + ∆T (2)
∆T = {(TF−TM) + (Td1 −Td2)}/2 (3)
The slave terminal advances or retards its sampling timing based on the time ∆T calculated from
equation (3), thereby reducing the sampling time difference with the master terminal to zero.
This adjustment is performed by varying the interval of the sampling pulse generated by an
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oscillator in the slave terminal.
The difference of the transmission delay time Tdd (= Td1 −Td2) is set to zero when sending and
receiving take the same route and exhibit equal delays. When the route is separate and the
sending and receiving delays are different, Tdd must be set at each terminal to be equal to the
sending delay time minus the receiving delay time. The maximum Tdd that can be set is 10ms.
(For setting, see Section 4.2.6.7. The setting elements of transmission delay time difference are
TCDT1 and TCDT2.)
The time TMmeasured at the master terminal is sent to the slave terminal together with the
current data and is used to calculate the ∆T.
The permissible maximum transmission delay time of the channel is 10ms.
In case of the three-terminal line application, the communication ports of the GRL100 are
interlinked with each other as shown in Figure 2.2.7.2, that is, port CH1 of one terminal and port
CH2 of the other terminal are interlinked. For the setup of the communication system, see
Section 2.2.13.3.
When terminal A is set as the master terminal by the scheme switch [SP.SYN], the
synchronization control is performed between terminals A and B, and terminals B and C. The
terminal B follows the terminal A and the terminal C follows the terminal B. The slave terminals
perform the follow-up control at their communication port CH2.
When the master terminal is out-of-service in A-MODE, the slave terminal that is interlinked
with port 1 of the master terminal takes the master terminal function. In the case shown in Figure
2.2.7.2, terminal B takes the master terminal function when the master terminal A is
out-of-service. In B-MODE and GPS-MODE, even if the master terminal is out-of-service, the
master terminal is not changed. If DC power supply of the out-of-service terminal is “OFF”,
differential elements at all terminals are blocked. Therefore, the [TERM] setting change from
“3TERM” to “2TERM” is required.
GRL100
Terminal B
Terminal A
Terminal C
CH1
Communication
port
GRL100
GRL100
Master Slave
Slave
CH2 CH1
CH2
CH1 CH2
Figure 2.2.7.2 Communication Link in Three-terminal Line
Sampling address synchronization
The principle of sampling address synchronization control is indicated in Figure 2.2.7.3. After
time synchronization has been established, the slave terminal measures the time from sending its
own timing reference signal until it returns from the master terminal. The transmission delay
time Td1 from slave to master terminal can be calculated from equation (4).
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