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GE Power Management
L90 Line Differential Rela
UR Series Instruction Manual
L90 Revision:
Manual P/N: 1601-0081-B5 (GEK-106231B)
Cop
ht © 2001 GE Power Management
2.9X
GE Power Management
215 Anderson Avenue, Markham, Ontario
Canada L6E 1B3
Tel: (905) 294-6222 Fax: (905) 294-8512
Internet: http://www.GEindustrial.com/pm
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Manufactured under an
ISO9000 Registered system.
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GE Power Management
ADDENDUM
This Addendum contains information that relates to the L90 relay, version 2.9X. This addendum lists a number of
information items tha t appea r in the i nstruc tion manu al GEK-1 06231B (1 601-00 81-B5) bu t are not i ncluded i n the c urrent L90 operations.
The following functions/items are not yet available with the current version of the L90 relay:
• Signal Sources SRC 3 to SRC 6 (availability is pending for this release)
NOTE:
• The UCA2 specifications are not yet finalized. There will be changes to the object models described in Appendix
C: UCA/MMS.
GE Power Management
215 Anderson Avenue, Markham, Ontario
Canada L6E 1B3
Tel: (905) 294-6222 Fax: (905) 294-8512
Internet: http://www.GEindustrial.com/pm
TABLE OF CONTENTS
1. GETTING STARTED
1.1 IMPORTANT PROCEDURES
1.1.1 CAUTIONS AND WARNINGS ........................................................................... 1-1
1.1.2 INSPECTION CHE C KL IS T ......................... ... .. ................. ... ... ................. .. ........ 1-1
1.2 UR OVERVIEW
1.2.1 INTRODUCTION TO THE UR RELAY .............. .................................. ..............1-2
1.2.2 UR HARDWARE ARCHITECTURE.................................... ...............................1-3
1.2.3 UR SOFTWARE ARCHITECTURE ................... ..................................... ...........1-4
1.2.4 IMPORTANT UR CONCEPTS........................................................................... 1-4
1.3 URPC SOFTWARE
1.3.1 PC REQUIREMENTS ........................................................................................ 1-5
1.3.2 SOFTWARE INSTALLATION ............................................................................ 1-5
1.3.3 CONNECTING URPC® WITH THE L90............................................................ 1-6
1.4 UR HARDWARE
1.4.1 MOUNTING AND WIRING................................................................................. 1-8
1.4.2 COMMUNICATIONS.......................................................................................... 1-8
1.4.3 FACEPLATE DIS PL A Y ......... ................ ... ... ................. .. ................. ... ................ 1-8
1.5 USING THE RELAY
1.5.1 FACEPLATE KEYPAD.... ................. .. ................. ... ... ................. .. ................. ... .. 1-9
1.5.2 MENU NAVIGATION ......................................................................................... 1-9
1.5.3 MENU HIERARCHY ................................................................ ..........................1-9
1.5.4 RELAY ACTIVATION....................................................................................... 1-10
1.5.5 BATTERY TAB................................................................................................. 1-10
1.5.6 RELAY PASSWORDS..................................................................................... 1-10
1.5.7 FLEXLOGIC™ CUSTOMIZATION................................................................... 1-10
1.5.8 COMMISSIONING ........................................................................................... 1-10
2. PRODUCT DESCRIPTION
2.1 INTRODUCTION
2.1.1 OVERVIEW........................................................................................................ 2-1
2.1.2 FEATURES ........................................................................................................ 2-2
2.1.3 FUNCTIONALITY...............................................................................................2-3
2.1.4 ORDERING........................................................................................................ 2-4
2.2 PILOT CHANNEL
2.2.1 INTER-RELAY COMMUNICATIONS................................................................. 2-7
2.2.2 CHANNEL MONIT OR ..... ... ... ................ ... ................. ... .. ................. ... ................ 2-8
2.2.3 LOOPBACK TEST ................ .. ... ................. ... ................ ... ... ................. ... .......... 2-8
2.2.4 DIRECT TRANSFER TRIPPING ....................................................................... 2-8
2.3 PROTECTION & CONTROL FUNCTIONS
2.3.1 CURRENT DIFFERENTIAL PROTECTION ......................................................2-9
2.3.2 BACKUP PROTECTION.................................................................................... 2-9
2.3.3 MULTIPLE SETTINGS GROUPS...................................................................... 2-9
2.3.4 USER PROGRAMMABLE LOGIC ..................................................................... 2-9
2.3.5 CONFIGURABLE INPUTS AND OUTPUTS...................................................... 2-9
2.4 METERING & MONITORING FUNCTIONS
2.4.1 METERING ...................................................................................................... 2-10
2.4.2 EVENT RECORDS .......................................................................................... 2-10
2.4.3 OSCILLOGRAPHY .......................................................................................... 2-10
2.4.4 CT FAILURE / CURRENT UNBALANCE ALARM......................................... ..2-10
2.4.5 TRIP CIRCUIT MONITOR ......................................... ......................................2-10
2.4.6 SELF TEST ...................................................................................................... 2-10
2.5 OTHER FUNCTIONS
2.5.1 ALARMS .......................................................................................................... 2-11
2.5.2 LOCAL USER INTERFACE ............................................................................. 2-11
2.5.3 TIME SYNCHRONIZATION.............................................................................2-11
2.5.4 FUNCTION DIAGRAMS..................................................................................2-11
2.6 TECHNICAL SPECIFICATIONS
2.6.1 PROTECTION EL E M ENT S ............... ... ................. ... ................. .. ... ................. 2-13
2.6.2 USER PROGRAMMABLE ELEMENTS ........................................................... 2-16
2.6.3 MONITORING..................................................................................................2-16
2.6.4 METERING ...................................................................................................... 2-17
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L90 Line Differential Relay i
TABLE OF CONTENTS
2.6.5 INPUTS.............................................................................................................2-17
2.6.6 POWER SUPPLY.............................................................................................2-18
2.6.7 OUTPUTS.........................................................................................................2-18
2.6.8 COMMUNICATIONS ........................................................................................2-18
2.6.9 INTER-RELAY COMMUNICATIONS................................................................2-19
2.6.10 ENVIRONMENTAL...........................................................................................2-19
2.6.11 TYPE TESTS....................................................................................................2-20
2.6.12 PRODUCTION TESTS..................................................................... ................2-20
2.6.13 APPROVALS ....................................................................................................2-20
2.6.14 MAINTENANCE................................................................................................2-20
3. HARDWARE
4. HUMAN INTERFACES
3.1 DESCRIPTION
3.1.1 PANEL CUTOUT................................................................................................3-1
3.1.2 MODULE WITHDRAWAL / INSERTION............................................................3-4
3.1.3 REAR TERMINAL LA Y OU T ............................. ... ................. .. ... ................. ... .....3-5
3.1.4 REAR TERMINAL AS S IGNMENTS.... ... ... ................ ... ................. ... ................. ..3-5
3.2 WIRING
3.2.1 TYPICAL WIRING DIAGRAM.............................................................................3-6
3.2.2 DIELECTRIC STRENGTH RATINGS AND TESTING........................................3-7
3.2.3 CONTROL POWER............................................................................................3-7
3.2.4 CT/VT MODULES...... ... ... .. ................. ... ................. .. ................. ... ... ................. ..3-8
3.2.5 CONTACT INPUTS/OUTPUTS ........................................................................3-10
3.2.6 TRANSDUCER INP U TS/OUTPUTS................. ... ... ................ ... ................. ... ...3-16
3.2.7 RS232 FACEPLATE PROGRAM PORT ..........................................................3-17
3.2.8 CPU COMMUNICATION PORTS.....................................................................3-17
3.2.9 IRIG-B...............................................................................................................3-19
3.3 L90 CHANNEL COMMUNICATION
3.3.1 DESCRIPTION .................................................................................................3-20
3.3.2 FIBER: LED & ELED TRANSMITTERS............................................................3-21
3.3.3 FIBER-LASER TR ANSMITTERS ............... ... ... ................. ... ................ ... ... ......3-21
3.3.4 G.703 INTERFACE...........................................................................................3-22
3.3.5 RS422 INTERFACE .........................................................................................3-25
3.3.6 RS422 & FIBER INTERFACE ..........................................................................3-28
3.3.7 G.703 & FIBER INTERFACE............................................................................3-28
4.1 URPC® SOFTWARE INTERFACE
4.1.1 GRAPHICAL USER INTERFACE.......................................................................4-1
4.1.2 CREATING A SITE LIST ....................................................................................4-1
4.1.3 URPC
4.1.4 URPC
®
SOFTWARE OVERVIEW......................................................................4-1
®
SOFTWARE MAIN WINDOW ...............................................................4-3
4.2 FACEPLATE INTERFACE
4.2.1 FACEPLATE.......................................................................................................4-4
4.2.2 LED INDICATORS..... ... ... ................ ... ... ................. .. ................. ... ... ................. ..4-5
4.2.3 CUSTOM LABELING OF LEDs..........................................................................4-7
4.2.4 CUSTOMIZING THE DISPLAY MODULE..........................................................4-7
4.2.5 DISPLAY.............................................................................................................4-8
4.2.6 KEYPAD .............................................................................................................4-8
4.2.7 BREAKER CONTR OL ................... .. ... ................. ... ................ ... ... ................. ... ..4-9
4.2.8 MENUS..... ... ... ................. .. ................. ... ... ................ ... ................. ... ... .............. 4 - 10
4.2.9 CHANGING SETTINGS ................ ................ ... ... ................. .. ................. ... ... ...4-11
5. SETTINGS
5.1 OVERVIEW
5.1.1 SETTINGS MAIN MENU ....................................................................................5-1
5.1.2 INTRODUCTION TO ELEMENTS......................................................................5-3
5.1.3 INTRODUCTION TO AC SOURCES..................................................................5-4
5.2 PRODUCT SETUP
5.2.1 PASSWORD SECURITY....................................................................................5-7
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5.2.2 DISPLAY PROPERTIES.................................................................................... 5-8
5.2.3 COMMUNICATIONS.......................................................................................... 5-8
5.2.4 MODBUS
5.2.5 REAL TIME CLOCK......................................................................................... 5-15
5.2.6 FAULT REPORT.............................................................................................. 5-15
5.2.7 OSCILLOGRAPHY .......................................................................................... 5-16
5.2.8 DATA LOGGER .................... ................ ... ... ................. .. ................. ... .............. 5 - 18
5.2.9 DEMAND ... ................ ... ... ................. .. ................. ... ... ................. .. ... ................. 5-18
5.2.10 USER-PROGRAMMABLE LEDS................ ................. .. ................. ... .............. 5 - 20
5.2.11 FLEX STATE PARAMETERS.......................................................................... 5-21
5.2.12 USER-DEFINABLE DISPLAYS ....................................................................... 5-21
5.2.13 INSTALLATION................................................................................................ 5-23
®
USER MAP.................................................................................... 5-15
5.3 SYSTEM SETUP
5.3.1 AC INPUTS ...................................................................................................... 5-24
5.3.2 POWER SYSTEM............................................................................................ 5-25
5.3.3 SIGNAL SOURCES ......................................................................................... 5-26
5.3.4 L90 POWER SYSTEM..................................................................................... 5-28
5.3.5 LINE ................................................................................................................. 5-30
5.3.6 BREAKERS...................................................................................................... 5-31
5.3.7 FLEXCURVES™.............................................................................................. 5-34
5.4 FLEXLOGIC™
5.4.1 INTRODUCTION TO FLEXLOGIC™...............................................................5-35
5.4.2 FLEXLOGIC™ RULES .................................................................................... 5-43
5.4.3 FLEXLOGIC™ EVALUATION.......................................................................... 5-43
5.4.4 FLEXLOGIC™ PROC EDURE EXAMPLE.......................................................5-43
5.4.5 FLEXLOGIC™ EQUATION EDITOR............................................................... 5-48
5.4.6 FLEXLOGIC™ TIMERS................................................................................... 5-48
5.4.7 FLEXELEMENTS™ ......................................................................................... 5-49
5.5 GROUPED ELEMENTS
5.5.1 OVERVIEW...................................................................................................... 5-53
5.5.2 SETTING GROUP ....... ... ... ................ ... ................. ... ... ................ ... ................. 5-53
5.5.3 LINE DIFFERENTIAL ELEMENTS .................................................................. 5-53
5.5.4 CURRENT DIFFERENTIAL............................................ ................................ .5-54
5.5.5 STUB BUS ..... ................. ... ................ ... ... ................. ... ................ ... ... .............. 5 - 57
5.5.6 LINE PICKUP................................................................................................... 5-58
5.5.7 DISTANCE ....................................................................................................... 5-60
5.5.8 POWER SWING DETECT ............................................................................... 5-72
5.5.9 LOAD ENCROACHMENT....................................................................... .. .. .....5-78
5.5.10 CURRENT ELEMENTS ........................................ .. .........................................5-80
5.5.11 INVERSE TIME OVERCURRENT CURVE CHARACTERISTICS ..................5-81
5.5.12 PHASE CURRENT ..................... ........................................... .. ........................5-86
5.5.13 NEUTRAL CURRENT......................................................................................5-92
5.5.14 GROUND CURRENT.......................................................................................5-99
5.5.15 NEGATIVE SEQUENCE CURRENT .............................................................5-101
5.5.16 BREAKER FAILU R E............... ... ... ................. .. ................. ... ... ................. .. ....5-103
5.5.17 VOLTAGE ELEMENTS.................................................................................. 5-112
5.5.18 PHASE VOLTAGE......................................................................................... 5-113
5.5.19 NEUTRAL VOLT AG E ........ ................ ... ................. ... ................. .. ................. . 5 - 1 15
5.5.20 AUXILIARY VOLTAGE .................................................................................. 5-116
5.5.21 SUPERVISING ELEMENTS .......................................................................... 5-118
5.6 CONTROL ELEMENTS
5.6.1 OVERVIEW.................................................................................................... 5-125
5.6.2 SETTING GROUP S ........ ................. .. ... ................. ... ................. .. ... ............... 5 - 1 25
5.6.3 SYNCHROCHECK.........................................................................................5-126
5.6.4 AUTORECLOSE ....... ................. ... ................. .. ... ................. ... ................. .. ... . 5-130
5.6.5 DIGITAL ELEMENTS..................................................................................... 5-137
5.6.6 DIGITAL COUNTERS.................................................................................... 5-140
5.6.7 MONITORING ELEMENTS ...........................................................................5-142
5.6.8 BREAKER ARCING CURRENT....................................................................5-142
5.6.9 CONTINUOUS MONITOR ............................................................................. 5-144
5.6.10 CT FAILURE DETECTOR .............................................................................5-145
5.6.11 VT FUSE FAILURE........................................................................................5-147
5.6.12 PILOT SCHEMES ...................... ... ................. .. ... ................. ... ................. .. ... . 5-148
5.7 INPUTS / OUTPUTS
5.7.1 CONTACT INPUTS........................................................................................ 5-151
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L90 Line Differential Relay iii
TABLE OF CONTENTS
5.7.2 VIRTUAL INPUTS ..........................................................................................5-153
5.7.3 UCA SBO TIMER ...........................................................................................5-154
5.7.4 CONTACT OUTPUTS ....................................................................................5-154
5.7.5 VIRTUAL OUTPUTS ......................................................................................5-155
5.7.6 REMOTE DEVICES........................................................................................5-155
5.7.7 REMOTE INPUTS ..........................................................................................5-156
5.7.8 REMOTE OUTPUTS: DNA BIT PAIRS ..........................................................5-157
5.7.9 REMOTE OUTPUTS: UserSt BIT PAIRS.......................................................5-158
5.7.10 DIRECT INPUTS /OUTPUTS ........... ................. ... ... ................ ... ................. ... .5-158
5.7.11 RESETTING .................................. .. ... ................. ... ................ ... ... ................. . 5 - 1 60
5.8 TRANSDUCER I/O
5.8.1 DCMA INPUTS ...............................................................................................5-161
5.8.2 RTD INPUTS ................ ... ................ ... ... ................. .. ................. ... ... ............... 5 - 1 62
5.9 TESTING
5.9.1 TEST MODE... ... .. ................. ... ................. .. ... ................. ... ................. .. ... .......5-163
5.9.2 FORCE CONTACT IN P U TS.... ... ... .. ................. ... ................. .. ... ................. ... .5-163
5.9.3 FORCE CONTACT OU TPUTS.............. ... ................ ... ................. ... ............... 5 - 1 63
5.9.4 CHANNEL TESTS ..... ... ................. .. ................. ... ... ................ ... ................. ... .5-164
6. ACTUAL VALUES
6.1 OVERVIEW
6.1.1 ACTUAL VALUES MAIN MENU .........................................................................6-1
6.2 STATUS
6.2.1 CONTACT INPUTS ............................................................................................6-3
6.2.2 VIRTUAL INPUTS ..............................................................................................6-3
6.2.3 REMOTE INPUTS ..............................................................................................6-3
6.2.4 DIRECT INPUTS ............... ... ... ................. .. ... ................. ... ................. .. ... ...........6- 4
6.2.5 CONTACT OUTPUTS ........................................................................................6-4
6.2.6 VIRTUAL OUTPUTS ..........................................................................................6-4
6.2.7 AUTORECLOSE.................................................................................................6-5
6.2.8 REMOTE DEVICES STATUS ............................................................................6-5
6.2.9 REMOTE DEVICES STATISTICS......................................................................6-5
6.2.10 CHANNEL TESTS ..... ... ................. .. ................. ... ... ................ ... ................. ... ... ..6-6
6.2.11 DIGITAL COUNTERS.........................................................................................6-7
6.2.12 FLEX STATES....................................................................................................6-7
6.2.13 ETHERNET ........................................................................................................6-7
6.3 METERING
6.3.1 METERING CONV E N TIO N S ..... ................ ... ... ................. ... ................ ... ...........6-8
6.3.2 87L DIFFERENTIAL CURRENT.......................................... .. ...........................6-11
6.3.3 SOURCES................................................................. .......................................6-12
6.3.4 SYNCHROCHECK................................................ .. .......................... .. .. ...........6-15
6.3.5 TRACKING FREQU E N CY.... ... ... ................ ... ... ................. ... ................ ... ... ......6-16
6.3.6 FLEXELEMENT S ™............................... ... ................ ... ... ................. ... .............. 6 - 16
6.3.7 TRANSDUCER I/O .... ... ................. .. ................. ... ... ................ ... ................. ... ...6-17
6.4 RECORDS
6.4.1 FAULT REPORTS............................................................................................6-18
6.4.2 EVENT RECORDS...........................................................................................6-20
6.4.3 OSCILLOGRAPHY...........................................................................................6-20
6.4.4 DATA LOGGER............................. .. ................. ... ... ................ ... ................. ... ...6-20
6.4.5 MAINTENANC E.................... ... ... ................ ... ................. ... ................. .. ............6-21
6.5 PRODUCT INFORMATION
6.5.1 MODEL INFORMATION...................................................................................6-22
6.5.2 FIRMWARE REVISIONS..................................................................................6-22
7. COMMANDS AND
TARGETS
7.1 COMMANDS
7.1.1 COMMANDS MENU...........................................................................................7-1
7.1.2 VIRTUAL INPUTS ..............................................................................................7-1
7.1.3 CLEAR RECORDS.............................................................................................7-1
7.1.4 SET DATE AND TIME ..... .. ... ................. ... .. ................. ... ................. ... ................7-2
7.1.5 RELAY MAINTENANCE.....................................................................................7-2
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7.2 TARGETS
7.2.1 TARGETS MENU............................................................................................... 7-3
7.2.2 RELAY SELF-TESTS......................................................................................... 7-3
8. THEORY OF OPERATION
8.1 OVERVIEW
8.1.1 INTRODUCTION................................................................................................8-1
8.1.2 ARCHITECTURE ............................................................................................... 8-1
8.1.3 REMOVAL OF DECAYING OFFSET................................................................. 8-2
8.1.4 PHASELET COMPUTATION............................................................................. 8-2
8.1.5 ADAPTIVE STRATEGY..................................................................................... 8-3
8.1.6 DISTURBANCE D ET EC TION.................. ... ... ................ ... ................. ... ... .......... 8-3
8.1.7 FAULT DETECTION.......................................................................................... 8-3
8.1.8 CLOCK SYNCHRONIZATION...........................................................................8-5
8.1.9 FREQUENCY TRACKING AND PHASE LOCKING.......................................... 8-6
8.1.10 FREQUENCY DETECTION............................................................................... 8-6
8.1.11 PHASE DETECTION ......................................................................................... 8-7
8.1.12 PHASE LOCKING FILTER .............................................................................. 8-10
8.1.13 CLOCK IMPLEMENTATION............................................................................ 8-12
8.1.14 MATCHING PHASELETS................................................................................ 8-12
8.1.15 START-UP ....................................................................................................... 8-13
8.1.16 HARDWARE AND COMMUNICATION REQUIREMENTS ............................. 8-13
8.1.17 ON-LINE ESTIMATE OF MEASUREMENT ERRORS ....................................8-13
8.1.18 CT SATURATION DETECTION ...................................................................... 8-14
8.1.19 CHARGING CURRENT COMPENSATION.....................................................8-14
8.1.20 DIFFERENTIAL ELEMENT CHARACTERISTICS........................................... 8-16
8.1.21 RELAY SYNCHRONIZATION..........................................................................8-16
8.2 OPERATING CONDITION CALCULATIONS
8.2.1 DEFINITIONS .................................................................................................. 8-18
8.2.2 2 TERMINAL MODE ........................................................................................ 8-18
8.2.3 TRIP DECISION EXAMPLE............................................................................. 8-22
8.2.4 TRIP DECISION TEST .................................................................................... 8-22
9. APPLICATION OF
SETTINGS
9.1 L90 CT REQUIREMENTS
9.1.1 INTRODUCTION................................................................................................9-1
9.1.2 CALCULATION EXAMPLE 1 ............................................................................. 9-1
9.1.3 CALCULATION EXAMPLE 2 ............................................................................. 9-2
9.2 CURRENT DIFFERENTIAL (87L) SETTINGS
9.2.1 INTRODUCTION................................................................................................9-3
9.2.2 CURRENT DIFF PICKUP...................................................................... ............9-3
9.2.3 CURRENT DIFF RESTRAINT 1......................................... ...............................9-3
9.2.4 CURRENT DIFF RESTRAINT 2......................................... ...............................9-3
9.2.5 CURRENT DIFF BREAK PT.................................... .. ........................................9-3
9.2.6 CT TAP .............................................................................................................. 9-4
9.3 DISTANCE BACKUP/SUPERVISION
9.3.1 DESCRIPTION................................................................................................... 9-5
9.3.2 PHASE DISTANCE............................................................................................ 9-6
9.3.3 GROUND DISTANCE ........................................................................................9-6
9.4 POTT SIGNALING SCHEME
9.4.1 DESCRIPTION................................................................................................... 9-7
9.5 SERIES COMPENSATED LINES
9.5.1 DISTANCE SETTINGS ON SERIES COMPENSATED LINES ......................... 9-8
9.6 LINES WITH TAPPED TRANSFORMERS
9.6.1 DESCRIPTION................................................................................................... 9-9
9.6.2 TRANSFORMER LOAD CURRENTS....................................................... .........9-9
9.6.3 FAULTS AT THE LV SIDE OF THE TRANSFORMER(S)............................... 9-10
9.6.4 EXTERNAL GROUND FAULTS......................................................................9-10
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10. COMMISSIONING
10.1 PRODUCT SETUP
10.1.1 PRODUCT SETUP............................ .. ................................................... .. ........10-1
10.2 SYSTEM SETUP
10.2.1 SYSTEM SETUP ..............................................................................................10-8
10.2.2 FLEXCURVE™ A ...........................................................................................10-10
10.2.3 FLEXCURVE™ B ...........................................................................................10-11
10.3 FLEXLOGIC™
10.3.1 FLEXLOGIC™ ................................................................................................10-12
10.4 GROUPED ELEMENTS
10.4.1 GROUPED ELEMENTS .................................................................................10-21
10.5 CONTROL ELEMENTS
10.5.1 SETTINGS TABLE .........................................................................................10-27
10.6 INPUTS / OUTPUTS
10.6.1 CONTACT INPUTS ........................................................................................10-32
10.6.2 VIRTUAL INPUTS ..........................................................................................10-33
10.6.3 UCA SBO TIMER ...........................................................................................10-33
10.6.4 CONTACT OUTPUTS ....................................................................................10-34
10.6.5 VIRTUAL OUTPUTS ......................................................................................10-35
10.6.6 REMOTE DEVICES........................................................................................10-36
10.6.7 REMOTE INPUTS ..........................................................................................10-37
10.6.8 REMOTE OUTPUTS ......................................................................................10-38
10.6.9 DIRECT MESSAG ING..... .. ................. ... ... ................ ... ................. ... ... ............1 0 - 39
10.6.10 RESETTING ... ... ................ ... ................. ... .. ................. ... ................. ... .. ..........10- 39
10.7 TRANSDUCER I/O
10.7.1 DCMA INPUTS ...............................................................................................10-40
10.7.2 RTD INPUTS ................ ... ................ ... ... ................. .. ................. ... ... ............... 1 0 - 41
10.8 TESTING
10.8.1 FORCE CONTACT IN P U TS /OUTPUTS................... ... ................. ... ... ............1 0 - 42
10.8.2 CHANNEL TESTS ..... ... ................. .. ................. ... ... ................ ... ................. ... .10-42
10.9 L90 COMMISSIONING TESTS
10.9.1 CHANNEL TESTING. ................. ... .. ................. ... ................. .. ... ................. ... .10-43
10.9.2 CLOCK SYNCHRONIZATION TESTS ...........................................................10-44
10.9.3 CURRENT DIFFERENTIAL............................................................................10-45
10.9.4 LOCAL-REMOTE RELAY TESTS..................................................................10-46
A. FLEXANALOG
PARAMETERS
B. MODBUS® RTU PROTOCOL
A.1 PARAMETER LIST
A.1.1 FLEXANALOG PARAMETER LIST................................................................... A-1
B.1 OVERVIEW
B.1.1 INTRODUCTION. ..............................................................................................B-1
B.1.2 PHYSICAL LAYER ............................................................................................ B-1
B.1.3 DATA LINK LAYER ........................................................................................... B-1
B.1.4 CRC-16 ALGORITHM.......................................................................................B-3
B.2 FUNCTION CODES
B.2.1 SUPPORTED FUNCTION CODES...................................................................B-4
B.2.2 03/04H: READ ACTUAL VALUES/SETTINGS.................................................. B-4
B.2.3 05H: EXECUTE OPERATION ........................................................................... B-5
B.2.4 06H: STORE SINGLE SETTING....................................................................... B-5
B.2.5 10H: STORE MULTIPLE SETTINGS ................................................................B-6
B.2.6 EXCEPTION RESPONSES............................................................................... B-6
B.3 FILE TRANSFERS
B.3.1 OBTAINING UR FILES USING MODBUS® PROTOCOL ................................. B-7
B.3.2 MODBUS
®
PASSWORD OPERATION............................................................. B-8
B.4 MEMORY MAPPING
B.4.1 MODBUS® MEMORY MAP .............................................................................. B-9
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B.4.2 MODBUS® MEMORY MAP DATA FORMATS................................................B-46
C. UCA/MMS
D. IEC 60870-5-104
E. DNP
F. MISCELLANEOUS
C.1 UCA/MMS OVERVIEW
C.1.1 UCA....................................................................................................................C-1
C.1.2 MMS...................................................................................................................C-1
C.1.3 UCA REPORTING .............................................................................................C-6
D.1 IEC 60870-5-104 POINTS LIST
D.1.1 INTEROPERABILTY DOCUM E NT .... ... ................. ... ... ................ ... ................. ..D-1
D.1.2 POINTS LIST .......... .. ................. ... ... ................ ... ................. ... ................. .. ... ...D-10
E.1 DNP DEVICE PROFILE
E.1.1 DNP V3.00 DEVICE PROFILE ..........................................................................E-1
E.2 DNP IMPLEMENTATION TABLE
E.2.1 IMPLEMENTATION TABLE...............................................................................E-4
E.3 DNP POINT LISTS
E.3.1 BINARY INPUT POINTS....................................................................................E-8
E.3.2 BINARY OUTPUT AND CONTROL RELAY OUTPUT ....................................E-13
E.3.3 COUNTERS .....................................................................................................E-14
E.3.4 ANALOG INPUTS............................................................................................E-15
F.1 CHANGE NOTES
F.1.1 REVISION HISTORY ......................... ... ................. ... ... ................ ... ... ................ F-1
F.1.2 CHANGES TO L90 MANUAL ............................................................................ F-1
F.2 STANDARD ABBREVIATIONS
F.2.1 ABBREVIATIONS .............................................................................................. F-4
F.3 TABLES AND FIGURES
F.3.1 LIST OF TABLES............................................................................................... F-6
F.3.2 LIST OF FIGURES.............................................................................................F-7
F.4 WARRANTY
F.4.1 GE POWER MANAGEMENT WARRANTY.....................................................F-10
GE Power Management
L90 Line Differential Relay vii
TABLE OF CONTENTS
viii L90 Line Differential Relay
GE Power Management
1 GETTING STARTED 1.1 IMPORTANT PROCEDURES
1 GETTING STARTED 1.1 IMPORTANT PROCEDURES
Please read this chapter to help guide you through the initial setup of your new relay.
1.1.1 CAUTIONS AND WARNINGS
Before attempting to install or use the relay, it is imperative that all WARNINGS and CAUTIONS in this manual are reviewed to he lp prev ent pe rs ona l injury, eq uipm ent da ma ge, an d/
WARNING CAUTION
• Open the relay packaging and inspect the unit for physical damage.
• Check that the battery ta b is inta ct on the power sup ply mo dule (for more details , see th e secti on BATTERY T AB in this
chapter).
• View the rear name-plate and verify that the correct model has been ordered.
or downtime.
1.1.2 INSPECTION CHECKLIST
1
Figure 1–1: REAR NAME-PLATE (EXAMPLE)
• Ensure that the following items are included:
• Instruction Manual
• Products CD (includes URPC software and manuals in PDF format)
• mounting screws
• registration card (attached as the last page of the manual)
• Fill out the registration form and mail it back to GE Power Management (include the serial number located on the rear
nameplate).
• For product information, instruction manual updates, and the latest software updates, please visit the GE Power Man-
agement Home Page.
If there is any noticeable physical damage, or any of the contents listed are missing, please contact GE
Power Management immediately.
NOTE
GE POWER MANAGEMENT
GE Power Management
215 Anderson Avenue
Markham, Ontario
Canada L6E 1B3
TELEPHONE: (905) 294-6222, 1-800-547-8629 (North Ame ric a only )
FAX: (905) 201-2098
E-MAIL: info.pm@indsys.g e.c om
HOME PAGE: http://www.GEindustrial.com/pm
CONTACT INFORMATION AND CALL CENTER FOR PRODUCT SUPPORT:
GE Power Management
L90 Line Differential Relay 1-1
1.2 UR OVERVIEW 1 GETTING STARTED
1.2 UR OVERVIEW 1.2.1 INTRODUCTION TO THE UR RELAY
1
Historically, substation protection, control, and metering functions were performed with electromechanical equipment. This
first generation of equipment was gradually replaced by analog electronic equipment, most of which emulated the singlefunction approach of their electromechanical precursors. Both of these technologies required expensive cabling and auxiliary equipment to produce functioning systems.
Recently, digital electronic equipment has begun to provide protection, control, and metering functions. Initially, this equipment was either single function or had very limited multi-function capability, and did not significantly reduce the cabling and
auxiliary equipment required. However, recent digital relays have become quite multi-functional, reducing cabling and auxiliaries significantly. These devices also transfer data to central control facilities and Human Machine Interfaces using electronic communications. The functions performed by these products have become so broad that many users now prefer the
term IED (Intelligent Electronic Device).
It is obvious to statio n desig ners that the amou nt of cabl ing and au xilia ry eq uipme nt inst alled in station s can be even furth er
reduced, to 20% to 70% of the levels common in 1990, to achieve large cost reductions. This requires placing even more
functions within the IEDs.
Users of power equipment are also interested in reducing cost by improving power quality and personnel productivity, and
as always, in increasing system reliability and efficiency. These objectives are realized through software which is used to
perform functions at both the station and supervisory levels. The use of these systems is growing rapidly.
High speed communications are required to meet the data transfer rates required by modern automatic control and monitoring systems. In the near future, very high speed communications will be required to perform protection signaling with a
performance target response time for a command signal between two IEDs, from transmission to reception, of less than 5
milliseconds. This has been established by the Electric Power Research Institute, a collective body of many American and
Canadian power utilities, in their Utilities Communications Architecture 2 (MMS/UCA2) project. In late 1998, some European utilities began to show an interest in this ongoing initiative.
IEDs with the capabilities outlined above will also provide significantly more power system data than is presently available,
enhance operations and maintenance, and permit the use of adaptive system configuration for protection and control systems. This new generation of equipment must also be easily incorporated into automation systems, at both the station and
enterprise levels. The GE Power Management Universal Relay (UR) has been developed to meet these goals.
1-2 L90 Line Differential Relay
GE Power Management
1 GETTING STARTED 1.2 UR OVERVIEW
1.2.2 UR HARDWARE ARCHITECTURE
Input Elements
Contact Inputs Contact Outputs
Virtual Inputs
Analog Inputs
CT Inputs
VT Inputs
Remote Inputs
Input
Status
Table
CPU Module Output Elements
Protective Elements
Logic Gates
Pickup
Dropout
Operate
Output
Status
Table
Virtual Outputs
Analog Outputs
Remote Outputs
-DNA
-USER
LAN
Programming
Device
Figure 1–2: UR CONCEPT BLOCK DIAGRAM
a) UR BASIC DESIGN
The UR is a digital-based device containing a central processing unit (CPU) that handles multiple types of input and output
signals. The UR can communicate over a local area network (LAN) with an operator interface, a programming device, or
another UR device.
The CPU module contains firmware that provides protection elements in the form of logic algorithms, as well as programmable logic gates, timers, and latches for control features.
Input elements accept a variety of analog or digital signals from the field. The UR isolates and converts these signals into
logic signals used by the relay.
Output elements con vert and isolate the logic signa ls gene rated by th e rela y into di gital or an alog si gnals that can be used
to control field devices.
Operator
Interface
827822A1.CDR
1
b) UR SIGNAL TYPES
The contact inputs and outputs are digital signals associated with connections to hard-wired contacts. Both ‘wet’ and
‘dry’ contacts are supported.
The virtual inputs and outputs are digital signals associated with UR internal logic signals. Virtual inputs include signals
generated by the local user interface. The virtual outputs are outputs of FlexLogic™ equations used to customize the UR
device. Virtual outputs can also serve as virtual inputs to FlexLogic™ equations.
The analog inputs an d outpu ts are si gnals that are associat ed w i th tra ns duc ers , s uch as R esi st anc e Temperature Detectors (RTDs).
The CT and VT inputs refer to ana log current tran sfor mer and vo ltage tra nsform er signals us ed to moni tor AC power lines .
The UR supports 1A and 5 A CTs.
The remote inputs and outputs provide a means of sharing digital point state information between remote UR devices.
The remote outputs interface to the remote inputs of other UR devices. Remote outputs are FlexLogic™ operands inserted
into UCA2 GOOSE messages and are of two assignment types: DNA standard functions and USER defined functions.
GE Power Management
L90 Line Differential Relay 1-3
1.2 UR OVERVIEW 1 GETTING STARTED
c) UR SCAN OPERATION
1
Read Inputs
Protection elements
serviced by sub-scan
Protective Elements
Solve Logic
Set Outputs
Figure 1–3: UR SCAN OPERATION
The UR device operates in a cyclic scan fashion. The UR reads the inputs into an input status table, solves the logic program (FlexLogic™ equati on), and then s ets e ach ou tput to the ap propriat e state in an ou tput st atus ta ble. An y resu lting t ask
execution is priority interrupt-driven.
PKP
DPO
OP
827823A1.CDR
1.2.3 UR SOFTWARE ARCHITECTURE
The firmware (software embedded in the relay) is designed in functional modules which can be installed in any relay as
required. This is achieved with Object-Oriented Design and Programming (OOD/OOP) techniques.
Object-Oriented techniques involve the use of ‘objects’ and ‘classes’. An ‘object’ is defined as “a logical entity that contains
both data and code that manipulates that data”. A ‘class’ is the generalized form of similar objects. By using this concept,
one can create a Protec ti on Cla ss w ith the Protec ti on El em ents as obj ec ts o f the cl ass s uch as Time Overcurrent, Instantaneous Overcurrent, Current Differential, Undervoltage, Overvoltage, Underfrequency, and Distance. These objects represent completely self-contained software modules. The same object-class concept can be used for Metering, I/O Control,
HMI, Communications, or any functional entity in the system.
Employing OOD/OOP in the software architecture of the Universal Relay achieves the same features as the hardware
architecture: modularity, scalability, and flexibility. The application software for any Universal Relay (e.g. Feeder Protection,
Transformer Protection, Distance Protection) is constructed by combining objects from the various functionality classes.
This results in a ’common look and feel’ across the entire family of UR platform-based applications.
1.2.4 IMPORTANT UR CONCEPTS
As described above, the arch itecture of th e UR rela y is different from prev ious de vice s. In orde r to achie ve a gen eral und erstanding of this device, some sections of Chapter 5 are quite helpful. The most important functions of the relay are contained in "Elements". A description of UR elements can be found in the INTRODUCTION TO ELEMENTS section. An
example of a simple element, and some of the organization of this manual, can be found in the DIGITAL ELEMENTS
MENU section. An explanation of the use of inputs from CTs and VTs is in the INTRODUCTION TO AC SOURCES section.
A description of how digital signals are used and routed within the relay is contained in the INTRODUCTION TO FLEXLOGIC™ section.
1-4 L90 Line Differential Relay
GE Power Management
1 GETTING STARTED 1.3 URPC SOFTWARE
1.3 URPC SOFTWARE 1.3.1 PC REQUIREMENTS
The Faceplate keypad and display or the URPC software interface can be used to communicate with the relay.
The URPC software interface is the preferred method to edit settings and view actual values because the PC monitor can
display more information in a simple comprehensible format.
The following minimum requirements must be met for the URPC software to properly operate on a PC.
Processor: Intel
RAM Memory: 64 MB minimum (128 MB recommended)
Hard Disk: 50 MB free space required before installation of URPC software
O/S: Windows
Device: CD-ROM drive
Port: COM1(2) / Ethernet
Refer to the following procedure to install the URPC software:
1. Start the Windows
2. Insert the URPC software CD into the CD-ROM drive.
3. If the installation program does not start automatically, choose Run from the Windows® Start menu and type
D:\SETUP.EXE. Press Enter to start the installation.
4. Follow the on-screen instructions to install the URPC software. When the Welcome window appears, click on Next to
continue with the installation procedure.
5. When the Choose Destination Location window appears and if the software is not to be located in the default direc-
tory, click Browse and type in the complete path name including the new directory name.
6. Click Next to continue with the installation procedure.
7. The default program group where the application will be added to is shown in the Select Program Folder window. If it
is desired that the application be added to an already existing program group, choose the group name from the list
shown.
8. Click Next to begin the installation process.
9. To launch the URPC application, click Finish in the Setup Complete window.
10. Subsequently, double click on the URPC software icon to activate the application.
Refer to the HUMAN INTERFACES chapter in this manual and the URPC Software Help program for more
information about the URPC software interface.
NOTE
®
Pentium 300 or higher
®
NT 4.x or Windows® 9x/2000
®
operating system.
1.3.2 SOFTWARE INSTALLATION
1
GE Power Management
L90 Line Differential Relay 1-5
1.3 URPC SOFTWARE 1 GETTING STARTED
1.3.3 CONNECTING URPC® WITH THE L90
1
This section is intended as a quick start guide to using the URPC software. Please refer to the URPC Help File and the
HUMAN INTERFACES chapter for more information.
a) CONFIGURING AN ETHERNET CONNECTION
Before starting, verify that the Ethernet network cable is properly connected to the Ethernet port on the back of the relay.
1. Start the URPC software. Enter the password "URPC" at the login password box.
2. Select the Help > Connection Wizard menu item to open the Connection Wizard. Click "Next" to continue.
3. Click the "New Interface" button to open the Edit New Interface window.
• Enter the desired interface name in the Enter Interface Name field.
• Select the "Ethernet" interface from the drop down list and press "Next" to continue.
4. Click the "New Device" button to open the Edit New Device Window.
• Enter the desired name in the Enter Interface Name field.
• Enter th e Modbus address o f the relay (fr om
PROTOCOL
• Enter the IP address (from
the
5. Click the " 4.1 Read Dev ice Inf ormation" button the n "OK" when the relay in formati on has been re ceiv ed. C lick "Next" to
continue.
6. Click the "New Site" button to open the Edit Site Name window.
• Enter the desired site name in the
7. Click the "OK" b utt on then click "F inish ". The ne w Site Lis t tree wil l be ad ded to th e Site Li st wi ndow (or O nline window)
located in the top left corner of the main URPC window.
The Site Device has now been configured for Ethernet communications. Proceed to Section c) CONNECTING TO THE
RELAY below to begin communications.
Ö
MODBUS SLAVE ADDRESS) in the
Enter TCPIP Address
SETTINGS Ö PRODUCT SETUP ÖØ COMMUNICATIONS ÖØ NETWORK Ö IP ADDRESS) in
field.
Enter Site Name
SETTINGS
Enter Modbus Address
field.
Ö
PRODUCT SETUP ÖØ COMMUNICATIONS ÖØ MODBUS
field.
b) CONFIGURING AN RS232 CONNECTION
Before starting, verify that the RS232 serial cable is properly connected to the RS232 port on the front panel of the relay.
1. Start the URPC software. Enter the password "URPC" at the login password box.
2. Select the
3. Click the "New Interface" button to open the Edit New Interface window.
• Enter the desired interface name in the
• Select the "RS232" interface from the drop down list and press "Next" to continue.
4. Click the "New Device" button to open the Edit New Device Window.
• Enter the desired name in the
• Enter the PC COM port number in the
5. Click "OK" then click "Next" to continue.
6. Click the "New Site" button to open the Edit Site Name window.
• Enter the desired site name in the
7. Click the "OK" b utt on then click "F inish ". The ne w Site Lis t tree wil l be ad ded to th e Site Li st wi ndow (or O nline window)
located in the top left corner of the main URPC window.
The Site Device has now been configured for RS232 communications. Proceed to Section c) CONNECTING TO THE
RELAY below to begin communications.
Help > Connection Wizard
Enter Interface Name
menu item to open the Connection Wizard. Click "Next" to continue.
Enter Interface Name
COM Port
Enter Site Name
field.
field.
field.
field.
1-6 L90 Line Differential Relay
GE Power Management
1 GETTING STARTED 1.3 URPC SOFTWARE
c) CONNECTING TO THE RELAY
1. Select the Display Properties window through the Site List tree as shown below:
1
2. The Display Properties window will open with a flashing status indicator.
• If the indicator is red, click the Connect button (lightning bolt) in the menu bar of the Displayed Properties window.
3. In a few moments, the flashing light should turn green, indicating that URPC is communicating with the relay.
Refer to the HUMAN INTERFACES chapter in this manual and the URPC Software Help program for more
information about the URPC software interface.
NOTE
GE Power Management
L90 Line Differential Relay 1-7
1.4 UR HARDWARE 1 GETTING STARTED
1.4 UR HARDWARE 1.4.1 MOUNTING AND WIRING
1
Please refer to the HARDWARE chapter for detailed relay mounting and wiring instructions. Review all WARNINGS AND
CAUTIONS.
1.4.2 COMMUNICATIONS
The URPC software communicates to the relay via the faceplate RS232 port or the rear panel RS485 / Ethernet ports. To
communicate via the faceplate RS232 port, a standard “straight-through” serial cable is used. The DB-9 male end is connected to the relay and the DB-9 or DB-25 female end is connected to the PC COM1 or COM2 port as described in the
HARDWARE chapter.
Figure 1–4: RELAY COMMUNICATIONS OPTIONS
To communicate through the L90 rear RS485 port from a PC RS232 port, the GE Power Management RS232/RS485 converter box is required. This device (catalog number F485) connects to the computer using a "straight-through" serial cable.
A shielded twisted-pair (20, 22, or 24 AWG) connects the F485 converter to the L90 rear communications port. The converter terminals (+, –, GND) are connected to the L90 communication module (+, –, COM) terminals. Refer to the CPU
COMMUNICATION PORTS section in the HARDWARE chapter for opti on details. The line shou ld b e te rmi nated with an RC network (i.e. 120 Ω, 1 nF) as described in the HARDWARE chapter.
1.4.3 FACEPLATE DISPLAY
All messages are display ed on a 2 × 20 characte r vacuum fluo rescen t displa y to make them visi ble unde r poor lighti ng conditions. Messages are displayed in English and do not require the aid of an instruction manual for deciphering. While the
keypad and display are not actively being used, the display will default to defined messages. Any high priority event driven
message will automatically override the default message and appear on the display.
1-8 L90 Line Differential Relay
GE Power Management
1 GETTING STARTED 1.5 USING THE RELAY
1.5 USING THE RELAY 1.5.1 FACEPLATE KEYPAD
Display messages are organized into ‘pages’ under the following headings: Actual Values, Settings, Commands, and Targets. The key navigates through these pages. Each heading page is broken down further into logical subgroups.
The MESSAGE keys navigate through the subgro ups. The VALUE keys scroll increment or decreme nt
numerical setting values when in programming mode. These keys also scroll through alphanumeric values in the text edit
mode. Alternatively, values may also be entered with the numeric keypad.
The key initiates and adv ance to the next chara cte r in te xt e dit mod e or e nters a decimal poin t. The key may be
pressed at any time for context sensitive help messages. The key stores altered setting values.
1.5.2 MENU NAVIGATION
Press the key to select the desired header display page (top-level menu). The header title appears momentarily followed by a header display page menu item. Each press of the key advances through the main heading pages as
illustrated below.
Ö
Ö
ACTUAL VALUES SETTINGS COMMANDS
ØØØØ
ACTUAL VALUES
STATUS
SETTINGS
PRODUCT SETUP
Ö
Ö
COMMANDS
VIRTUAL INPUTS
Ö
Ö
TARGETS
No Active
Targets
1
Ö
Ö
USER DISPLAYS
when in use
(
Ø
User Display 1
The setting and actual value messages are arranged hierarchically. The header display pages are indicated by double
scroll bar characters (
pages represent the highest level of the hierarchy and the sub-header display pages fall below this level. The MESSAGE
and keys move within a group of headers, sub-headers, setting values, or actual values. Continually pressing the
MESSAGE key from a header display displays specific information for the header category. Conversely, continually
pressing the MESSAGE key from a setting value or actual value display returns to the header display.
HIGHEST LEVEL LOWEST LEVEL (SETTING VALUE)
SETTINGS
PRODUCT SETUP
SETTINGS
SYSTEM SETUP
)
1.5.3 MENU HIERARCHY
), while sub-header pages are indicated by single scroll bar characters (
PASSWORD
SECURITY
ACCESS LEVEL:
Restricted
). The head er displ ay
GE Power Management
L90 Line Differential Relay 1-9
1.5 USING THE RELAY 1 GETTING STARTED
1.5.4 RELAY ACTIVATION
1
The relay is defaulted to the "Not Programmed" state when it leaves the factory. This safeguards against the installation of
a relay whose settings have not been entered. When powered up successfully, the TROUBLE indicator will be on and the
IN SERVICE indicator off. The relay in the "Not Programmed" state will block signaling of any output relay. These conditions will remain until the relay is explicitly put in the "Programmed" state.
Select the menu message
RELAY SETTINGS:
Not Programmed
To put the relay in the "Programmed" state, press either of the VALUE keys once and then press . The faceplate TROUBLE indicator will turn off and the IN SERVICE indicator will turn on. The settings for the relay can be programmed manually (refer to the SETTINGS chapter) via the faceplate keypad or remotely (refer to the URPC Help file) via
the URPC software interface.
The battery tab is installed in the power supply module before the L90 shipped from the factory. The battery tab prolongs
battery life in the event the relay is powered down for long periods of time before installation. The battery is responsible for
backing up event records, oscillography, data logger, and real-time clock information when the relay is powered off. The
battery failure self-te st error gen erated by the relay is a m inor and s hould no t af fect the rel ay functio nality. When the relay is
installed and ready for co mmis sioni ng, the tab sh ould be rem oved. The battery tab should be re-inserte d if the relay is powered off for an extended period of time. If required, contact the factory for a replacement battery or battery tab.
SETTINGS Ö PRODUCT SETUP ÖØ INSTALLATION Ö RELAY SETTINGS
1.5.5 BATTERY TAB
1.5.6 RELAY PASSWORDS
It is recommended that passwords be set up for each security level and assigned to specific personnel. There are two user
password SECURITY access levels:
1. COMMAND
The COMMAND access level restricts the user from making any settings changes, but allows the user to perform the following operations:
• operate breakers via faceplate keypad
• change state of virtual inputs
• clear event records
• clear oscillography records
2. SETTING
The SETTING access level allows the user to make any changes to any of the setting values.
Refer to the CHANGING SETTINGS section (in the HUMAN INTERFACES chapter) for complete instructions
on setting up security level passwords.
NOTE
1.5.7 FLEXLOGIC™ CUSTOMIZATION
FlexLogic™ equation editing is required for setting up user-defined logic for customizing the relay operations. See section
FLEXLOGIC™ in the SETTINGS chapter.
1.5.8 COMMISSIONING
Templated tables for charting all the required settings before entering them via the keypad are available in the COMMISSIONING chapter, which also includes instructions for commissioning tests.
1-10 L90 Line Differential Relay
GE Power Management
2 PRODUCT DESCRIPTION 2.1 INTRODUCTION
2 PRODUCT DESCRIPTION 2.1 INTRODUCTION 2.1.1 OVERVIEW
The L90 relay is a digital current differential relay system with an integral communications channel interface.
The L90 is intended to provide complete protection for transmission lines of any voltage level. Both three phase and single
phase tripping schemes are available. Models of the L90 are available for application on both two and three terminal lines.
The L90 uses per phase differential at 64 kbps transmitting 2 phaselets per cycle. The current differential scheme is based
on innovative patented techniques developed by GE. The L90 algorithms are based on the Fourier transform–phaselet
approach and an adaptive statistical restraint. The restraint is similar to a traditional percentage differential scheme, but is
adaptive based on relay measurements. When used with a 64 kbps channel, the innovative “phaselets” approach yields an
operating time of 1.0 to 1.5 cycles typical. The adaptive statistical restraint approach provides both more sensitive and
more accurate fault sensin g. This al lows the L90 to dete ct relati vely higher im pedan ce sin gle line to gro und f aults th at existing systems may not. The basic current differential element operates on current input only. Long lines with significant
capacitance can ben efit from charg ing cu rrent com pens ation i f termin al vol tage me asurem ents a re appli ed to the relay. The
voltage input is also used for some protection and monitoring features such as directional elements, fault locator, metering,
and distance backup.
The L90 is designed to operate over different communications links with various degrees of noise encountered in power
systems and communications environments. Since correct operation of the relay is completely dependent on data received
from the remote end, special attention must be paid to information validation. The L90 incorporates a high degree of security by using a 32-bit CRC (cyclic redundancy code) inter-relay communications packet.
In addition to current differential protection, the relay provides multiple backup protection for phase and ground faults. For
overcurrent prot ect ion , th e time overcurrent c urve s may be s ele cte d fro m a selection of stan dard cu rve shapes or a custom
FlexCurve™ for optimum co-ordination. Additionally, one zone of phase and ground distance protection with power swing
blocking, out-of-step tripping, line pickup, load encroachment, and POTT features is included.
The L90 incorporates charging current compensation for applications on very long transmission lines without loss of sensitivity. The line capacitive current is removed from the terminal phasors.
The relay uses a sampling rate of 64 samples per cycle to provide metering values and flexible oscillography.
Voltage and current metering is included as a standard feature. Additionally, currents are available as total RMS values.
Power, power factor and frequency measurements are also provided.
Diagnostic feature s inc lude a seque nce of record s of 10 24 tim e-tagge d eve nts. Th e intern al cl ock u sed fo r time-tagg ing ca n
be synchronized with an IRIG-B signal. This precise time stamping allows the sequence of events to be determined
throughout the system. Events can also be programmed (via FlexLogic™ equations) to trigger oscillography data capture
which may be set to record the measured parameters before and after the event for viewing on a portable computer (PC).
These tools will significantly reduce troubleshooting time and simplify report generation in the event of system faults.
A faceplate RS232 port may be used to connect a PC for programming settings and for monitoring actual values. A variety
of communications modules are available. Two rear RS485 ports are standard to allow independent access by operating
and engineering staff. All serial ports use the Modbus
puters with baud rates up to 115.2 kbps. The RS232 port has a fixed baud rate of 19.2 kbps. Optional communications
modules include a 10BaseF Eth ern et interfa ce whic h can b e used t o provi de fast, reliabl e commu nicati ons in noisy enviro nments. Another option provides two 10BaseF fiber optic ports for redundancy. The Ethernet port supports MMS/UCA2 protocol.
The relay uses flash memory technology which allows field upgrading as new features are added.
The testing features can be used to verify and test settings and operations.
®
RTU protocol. The RS485 ports may be connected to system com-
2
GE Power Management
L90 Line Differential Relay 2-1
2.1 INTRODUCTION 2 PRODUCT DESCRIPTION
2.1.2 FEATURES
LINE CURRENT DIFFERENTIAL:
• Phase segregated, high-speed digital current differential system
• Overhead and underground AC transmission lines, series compensated lines
• Two and three terminal line applications
2
• Zero-sequence removal for application on lines with tapped transformers connected in a grounded Wye on the line
side
• GE phaselets approach based on Discrete Fourier Transform with 64 samples per cycle and transmitting 2 timestamped phaselets per cycle
• Adaptive restraint approach improving sensitivity and accuracy of fault sensing
• Increased security for trip decision using Disturbance Detector and Trip Output logic
• Continuous clock synchronization via the distributed synchronization technique
• Increased transient stability through DC decaying offset removal
• Accommodates up to 5 times CT ratio differences
• Peer-to-Peer (Master-Master) architecture changing to Master-Slave via DTT (if channel fails) at 64 kbps
• Charging current comp ens ati on
• Interfaces direct fiber, multiplexed RS422 and G.703 connections with relay ID check
• Per phase line differential protection Direct Transfer Trip plus 8 user-assigned pilot signals via the communications
channel
• Secure 32-bit CRC protection against communications errors
BACKUP PROTECTION:
• DTT provision for pilot schemes
• 1 zone distance protection with POTT scheme, power swing blocking/out-of-step tripping, line pickup, and load
encroachment
• 2-element TOC and 2-element IOC directional phase overcurrent protection
• 2-element TOC and 2-element IOC directional zero sequence overcurrent protection
• 2-element TOC and 2-element IOC negative sequence overcurrent protection
• Undervoltage and overvoltage protection
ADDITIONAL PROTECTION:
• Breaker failure protection
• Stub bus protection
• VT and CT supervision
• GE "Sources" approach allowing grouping of different CTs and VTs from multiple input channels
• Open pole detection
• Breaker trip coil supervision and "seal-in" of trip command
• FlexLogic™ allowing creation of user-defined distributed protection and control logic
CONTROL:
• 1 and 2 breakers configuration for 1½ and ring bus schemes, pushbutton control from the relay
• Auto-reclosing and synchrochecking
• Breaker arcing current
2-2 L90 Line Differential Relay
GE Power Management
2 PRODUCT DESCRIPTION 2.1 INTRODUCTION
MONITORING:
• Oscillography of current, voltage, FlexLogic™ operands, and digital signals (1× 128 cycles to 31 × 8 cycles config-
urable)
• Events recorder - 1024 events
• Fault locator
METERING:
• Actual 87L remote phasors, differential current and channel delay at all line terminals of line current differential protec-
tion
• Line current, voltage, real power, reactive power, apparent power, power factor, and frequency
COMMUNICATIONS:
• RS232 front port - 19.2 kbps
• 1 or 2 RS485 rear ports - up to 115 kbps
• 10BaseF Ethernet port supporting MMS/UCA2.0 protocol
2.1.3 FUNCTIONALITY
The following SINGLE LINE DIAGRAM illustrates relay functionality using ANSI (American National Standards Institute)
device numbers
2
52
Monitoring
50DD
(via Dedicated Communications)
79
CLOSE TRIP
51P(2)
51_2(2)
50_2(2)
50P(2)
Data From/To Remote End
L90 Line Differential Relay
Figure 2–1: SINGLE LINE DIAGRAM
50BF(2)
87L 21P
67P(2)
FlexElement
50G(2)
68
51G(2)
TM
78
Metering
50N(2)
51N(2)
Transducer
Inputs
59X
3V_0
21G67N/G
59P
27P(2)
59N
27X
25(2)
831706AS.CDR
GE Power Management
L90 Line Differential Relay 2-3
2.1 INTRODUCTION 2 PRODUCT DESCRIPTION
T able 2–1: DEVICE NUMBERS AND FUNCTIONS
2
DEVICE
NUMBER
21G Ground Distance 51N Neutral Time Overcurrent
21P Phase Distance 51P Phase Time Overcurrent
25 Synchrocheck 51_2 Negative Sequence Time Overcurrent
27P Phase Undervoltage 52 AC Circuit Breaker
27X Auxiliary Undervoltage 59N Neutral Overvoltage
50BF Breaker Failure 59P Phase Overvoltage
50DD Adaptive Fault Detector
50G Ground Instantaneous Overcurrent 67P Phase Directional Overcurrent
50N Neutral Instantaneous Overcurrent 68 Power Swing Blocking
50P Phase Instantaneous Overcurrent 78 Out-of-step Tripping
50_2 Negative Sequence Instantaneous Overcurrent 79 Automatic Recloser
51G Ground Time Overcurrent 87L Segregated Line Current Differential
FUNCTION DEVICE
(sensitive current disturbance detector)
Table 2–2: ADDITIONAL DEVICE FUNCTIONS
FUNCTION FUNCTION FUNCTION
Breaker Arcing Current (I
Breaker Control FlexLogic™ Equations Pilot Scheme (POTT)
Contact Inputs (up to 96) L90 Channel T ests Setting Groups (8)
Contact Outputs (up to 64) Line Pickup Stub Bus
CT Failure Detector Load Encroachment Transducer I/O
Data Logger Metering: Current, Voltage, Power,
Digital Counters (8) User Programmable LEDs
Digital Elements (16) Virtual Inputs (32)
Direct Inputs (8 per L90 comms channel) MMS/UCA Communications Virtual Outputs (64)
DNP 3.0 MMS/UCA Remote I/O ("GOOSE") VT Fuse Failure
Event Recorder ModBus Communications
Fault Locator ModBus User Map
Fault Reporting O pen Pole Detector
2
T) FlexElements™ Oscillography
NUMBER
FUNCTION
59X Auxiliary Overvoltage
67N Neutral Directional Overcurrent
Energy, Frequency, Demand,
Power Factor, 87L differential
current, local & remote phasors
User Definable displays
2.1.4 ORDERING
The relay is available as a 19-inch rack horizontal mount unit or as a reduced size (¾) vertical mount unit, and consists of
power supply, CPU, Digital Input/Output, Trans ducer I/O an d L90 C ommunic ations modul es. Eac h of these can be supp lied
in a number of configurations which must be specified at the time of ordering. The information required to completely specify the relay is provided in the followin g table.
2-4 L90 Line Differential Relay
GE Power Management
2 PRODUCT DESCRIPTION 2.1 INTRODUCTION
Table 2–3: ORDER CODES
L90 L90 -
Base Unit
CPU
Software
Mount /
Faceplate
Power
Supply
CT/VT
DSP
Digital I/O
Transducer
I/O (max of 4
per unit)
Inter-Relay
Communications
L90
00 - H C
00 - V F
| | ||| | | | | | | |
| | | | | | | | | | |
A
| | | | | | | | | | |
C
| | | | | | | | | | |
D
00
-F
- H
-F
||| | | | | | | |
| | | | | | | |
H C
| | | | | | | |
V F
|||||||
H
|||||||
L
8A
8C |
- L
- H
- L
| | | | | |
|
6A 6A 6A 6A 6A
6B 6B 6B 6B 6B
6C 6C 6C 6C 6C
6D 6D 6D 6D 6D
6E 6E 6E 6E 6E
6F 6F 6F 6F 6F
6G 6G 6G 6G 6G
6H 6H 6H 6H 6H
6K 6K 6K 6K 6K
6L 6L 6L 6L 6L
6M 6M 6M 6M 6M
6N 6N 6N 6N 6N
6P 6P 6P 6P 6P
6R 6R 6R 6R 6R
6S 6S 6S 6S 6S
6T 6T 6T 6T 6T
6U 6U 6U 6U 6U
5C 5C 5C 5C 5C |
5E 5E 5E 5E 5E |
5F 5F 5F 5F 5F |
N
S
|
XX XX XX XX
N
| | | |
_ _
U
For Full Sized Horizontal Mount
W
For Reduced Size Vertical Mount
R
Base Unit
RS485 + RS485 (ModBus RTU, DNP)
RS485 + 10BaseF (
RS485 + Redundant 10BaseF (
No Software Options
Horizontal (19” rack)
Vertical (3/4 size)
125 / 250 V AC/DC
24 to 48 V (DC only)
Standard 4CT/4VT
Standard 8CT
No Module
|
2 Form-A (Volt w/ opt Curr) & 2 Form-C outputs, 8 Digital Inputs
|
2 Form-A (Volt w/ opt Curr) & 4 Form-C Outputs, 4 Digital Inputs
|
8 Form-C Outputs
|
16 Digital Inputs
|
4 Form-C Outputs, 8 Digital Inputs
|
8 Fast Form-C Outputs
|
4 Form-A (Voltage w/ opt Current) Outputs, 8 Digital Inputs
|
6 Form-A (Voltage w/ opt Current) Outputs, 4 Digital Inputs
|
4 Form-C & 4 Fast Form-C Outputs
|
2 Form-A (Curr w/ opt Volt) & 2 Form-C Outputs, 8 Digital Inputs
|
2 Form-A (Curr w/ opt Volt) & 4 Form-C Outputs, 4 Digital Inputs
|
4 Form-A (Current w/ opt Voltage) Outputs, 8 Digital Inputs
|
6 Form-A (Current w/ opt Voltage) Outputs, 4 Digital Inputs
|
2 Form-A (No Monitoring) & 2 Form-C Outputs, 8 Digital Inputs
|
2 Form-A (No Monitoring) & 4 Form-C Outputs, 4 Digital Inputs
|
4 Form-A (No Monitoring) Outputs, 8 Digital Inputs
|
6 Form-A (No Monitoring) Outputs, 4 Digital Inputs
|
8 RTD Inputs
4 RTD Inputs, 4 dcmA Inputs
8 dcmA Inputs
820 nm, multi-mode, LED, 1 Channel
7A
1300 nm, multi-mode, LED, 1 Channel
7B
1300 nm, single-mode, ELED, 1 Channel
7C
1300 nm, single-mode, LASER, 1 Channel
7D
Channel 1: G.703; Channel 2: 820 nm, multi-mode LED
7E
Channel 1: G.703; Channel 2: 1300 nm, multi-mode LED
7F
Channel 1: G.703; Channel 2: 1300 nm, single-mode ELED
7G
Channel 1: G.703; Channel 2: 1300 nm, single-mode LASER
7Q
820 nm, multi-mode, LED, 2 Channels
7H
1300 nm, multi-mode, LED, 2 Channels
7I
1300 nm, single-mode, ELED, 2 Channels
7J
1300 nm, single-mode, LASER, 2 Channels
7K
Channel 1 - RS422; Channel 2 - 820 nm, multi-mode, LED
7L
Channel 1 - RS422; Channel 2 - 1300 nm, multi-mode, LED
7M
Channel 1 - RS422; Channel 2 - 1300 nm, single-mode, ELED
7N
Channel 1 - RS422; Channel 2 - 1300 nm, single-mode,
7P
G.703, 1 Channel
7R
RS422, 1 Channel
7T
G.703, 2 Channels
7S
RS422, 2 Channels
W
7
1550 nm, single-mode, LASER, 1 Channel
72
1550 nm, single-mode, LASER, 2 Channel
73
Channel 1 - RS422; Channel 2 - 1550 nm, single-mode, LASER
74
Channel 1 - G.703, Channel 2 - 1550 nm, single -mode, LASER
75
MMS/UCA2, Modbus TCP/IP, DNP
MMS/UCA2, Modbus TCP/IP, DNP
)
LASER
)
2
GE Power Management
L90 Line Differential Relay 2-5
2.1 INTRODUCTION 2 PRODUCT DESCRIPTION
The order codes for replacement modules to be ordered separately are shown in the following table. When ordering a
replacement CPU module or Faceplate, please provide the serial number of your existing unit.
Table 2–4: ORDER CODES FOR REPLACEMENT MODULES
-
POWER SUPPLY
UR
CPU
2
FACEPLATE
DIGITAL I/O
CT/VT DSP
L60 INTER-RELAY
COMMUNICATIONS
L90 INTER-RELAY
COMMUNICATIONS
TRANSDUCER I/O
-
| 1H |
| 1L |
|9A|
|9C|
|9D|
| 3C |
| 3F |
|6A|
|6B|
|6C|
|6D|
|6E|
|6F|
|6G|
|6H|
|6K|
|6L|
|6M|
|6N|
|6P|
|6R|
|6S|
|6T|
|6U|
| 8A |
| 8B |
| 8C |
| 8D |
| 8Z |
|7U|
|7V|
|7Y|
|7Z|
| 7A |
| 7B |
| 7C |
| 7D |
| 7E |
| 7F |
| 7G |
| 7Q |
| 7H |
| 7I |
| 7J |
| 7K |
| 7L |
| 7M |
| 7N |
| 7P |
| 7R |
| 7S |
| 7T |
| 7W |
| 72 |
| 73 |
| 74 |
| 75 |
|5C|
|5E|
|5F|
125 / 250 V AC/DC
24 - 48 V (DC only)
RS485 + RS485 (ModBus RTU, DNP 3.0)
RS485 + 10BaseF (MMS/UCA2, ModBus TCP/IP, D NP 3.0)
RS485 + Redundant 10BaseF (MMS/UCA2, ModBus TCP/IP, DNP 3.0)
Horizontal Faceplate with Display & Keypad
Vertical Faceplate with Display & Keypad
2 Form-A (Voltage w/ opt Current) & 2 Form-C Outputs, 8 Digital Inputs
2 Form-A (Voltage w/ opt Current) & 4 Form-C Outputs, 4 Digital Inputs
8 Form-C Outputs
16 Digital Inputs
4 Form-C Outputs, 8 Digital Inputs
8 Fast Form-C Outputs
4 Form-A (Voltage w/ opt Current) Outputs, 8 Digital Inputs
6 Form-A (Voltage w/ opt Current) Outputs, 4 Digital Inputs
4 Form-C & 4 Fast Form-C Outputs
2 Form-A (Current w/ opt Voltage) & 2 Form-C Outputs, 8 Digital Inputs
2 Form-A (Current w/ opt Voltage) & 4 Form-C Outputs, 4 Digital Inputs
4 Form-A (Current w/ opt Voltage) Outputs, 8 Digital Inputs
6 Form-A (Current w/ opt Voltage) Outputs, 4 Digital Inputs
2 Form-A (No Monitoring) & 2 Form-C Outputs, 8 Digital Inputs
2 Form-A (No Monitoring) & 4 Form-C Outputs, 4 Digital Inputs
4 Form-A (No Monitoring) Outputs, 8 Digital Inputs
6 Form-A (No Monitoring) Outputs, 4 Digital Inputs
Standard 4CT/4VT
Sensitive Ground 4CT/4VT
Standard 8CT
Sensitive Ground 8CT
HI-Z 4CT
110/125 V, 20 mA Input/Output Channel Interface
48/60 V, 20 mA Input/Output Channel Interface
125 V Input, 5V Output, 20 mA Channel Interface
5 V Input, 5V Output, 20 mA Channel Interface
820 nm, multi-mode, LED, 1 Channel
1300 nm, multi-mode, LED, 1 Channel
1300 nm, single-mode, ELED, 1 Channel
1300 nm, single-mode, LASER, 1 Channel
Channel 1: G.703; Channel 2: 820 nm, multi-mode LED
Channel 1: G.703; Channel 2: 1300 nm, multi-mode LED
Channel 1: G.703; Channel 2: 1300 nm, single-mode ELED
Channel 1: G.703; Channel 2: 820 nm, single-mode LASER
820 nm, multi-mode, LED, 2 Channels
1300 nm, multi-mode, LED, 2 Channels
1300 nm, single-mode, ELED, 2 Channels
1300 nm, single-mode, LASER, 2 Channels
Channel 1 - RS422; Channel 2 - 820 nm, multi-mode, LED
Channel 1 - RS422; Channel 2 - 1300 nm, multi-mode, LED
Channel 1 - RS422; Channel 2 - 1300 nm, single-mode, ELED
Channel 1 - RS422; Channel 2 - 1300 nm, single-mode, LASER
G.703, 1 Channel
G.703, 2 Channels
RS422, 1 Channel
RS422, 2 Channels
1550 nm, single-mode, LASER, 1 Channel
1550 nm, single-mode, LASER, 2 Channel
Channel 1 - RS422; Channel 2 - 1550 nm, single-mode, LASER
Channel 1 - G.703, Channel 2 - 1550 nm, single -mode, LASER
8 RTD Inputs
4 dcmA Inputs, 4 RTD Inputs
8 dcmA Inputs
2-6 L90 Line Differential Relay
GE Power Management
2 PRODUCT DESCRIPTION 2.2 PILOT CHANNEL
2.2 PILOT CHANNEL 2.2.1 INTER-RELAY COMMUNICATIONS
Dedicated inter-relay communications may operate over 64 kbps digital channels or dedicated fiber optic channels. Available interfaces inclu de:
• RS422 at 64 kbps
• G.703 at 64 kbps
• Dedicated fiber optics at 64 kbps. The fiber optic options include:
• 820 nm multi-mode fiber with an LED transmitter
• 1300 nm multi-mode fiber with an LED transmitter
• 1300 nm single-mode fiber with an ELED transmitter
• 1300 nm single-mode fiber with a LASER transmitter
• 1550 nm single-mode fiber with a LASER transmitter
All fiber optic options use an ST connector. L90 models are available for use on two or three terminal lines. A two terminal
line application requires one bi-directional channel. However, in two terminal line applications, it is also possible to use an
L90 relay with two bi-directional channels. The second bi-directional channel will provide a redundant backup channel with
automatic switchover if the first channel fails.
The L90 current differential relay is designed to function in a Peer to Peer or Master–Master architecture. In the Peer to
Peer architecture, all relays in the system are identical and perform identical functions in the current differential scheme. In
order for every relay on t he l ine to be a Peer, each relay must be able to communicate with all o f the other relays. If there i s
a failure in communications among the relays, the relays will revert to a Master - Slave architecture, with the Master as the
relay that has current phasors from all terminals. The use of two different operational modes is intended to increase the
dependability of the current differential scheme by reducing reliance on the communications.
The main difference between a Master and a Slave L90 is that only a Master relay performs the actual current differential
calculation, and only a Master relay communicates with the relays at all other terminals of the protected line.
At least one Master L90 relay must have live communications to all other terminals in the current differential scheme; the
other L90 relays on that line may operate as Slave relays. All Master relays in the scheme will be equal, and each will perform all functions. Each L9 0 rela y in the sche me wil l determ ine if it is a Master by com par ing the nu mber of te rminal s on the
line to the number of active communication channels.
The Slave terminals only communicate with the Master; there is no Slave to Slave communications path. As a result, a
Slave L90 relay cannot calculate the differential current. When a Master L90 relay issues a local trip signal, it also sends a
Direct Transfer Trip signal to all of the other L90 relays on the protected line.
If a Slave L90 relay issues a trip from one of its backup functions, it can send a transfer trip signal to its Master and other
Slave relays if such option is designated. Because a Slave cannot communicate with all the relays in the differential
scheme, the Master will then “broadcast” the Direct Transfer Trip signal to all other terminals.
The Slave L90 Relay performs the following functions:
• Samples currents and voltages
• Removes DC offset from the current via the mimic algorithm
• Creates phaselets
• Calculates sum of squares data
• Transmits current data to all Master L90 relays
• Performs all local relaying functions
• Receives Current Differential DTT and Direct Input signals from all other L90 relays
• Transmits Direct Output signals to all communicating relays
• Sends synchronization information of local clock to all other L90 clocks
The Master L90 Relay performs the following functions:
• Performs all functions of a Slave L90
• Receives current phasor inform ati on fr om all relay s
• Performs the Current Differential algorithm
• Sends a Current Differential DTT signal to all L90 relays on the protected line
2
GE Power Management
L90 Line Differential Relay 2-7
2.2 PILOT CHANNEL 2 PRODUCT DESCRIPTION
In the Peer to Peer mode, all L90 relays act as Masters.
2
L90 - 1
L90 - 1
Tx
CHn
Rx
CHn
Tx
Rx
OPTIONAL REDUNDANT CHANNEL
TYPICAL 2-TERMINAL APPLICATION
Tx
CHn
Rx
Tx
CHn
Rx
Rx
Tx
Tx
CHn
CHn
L90 - 3
Rx
CHn
Tx
Rx
Tx
Rx
Tx
Rx
Tx
Rx
L90 - 2
CHn
CHn
L90 - 2
CHn
TYPICAL 3-TERMINAL APPLICATION
831009A4.CDR
Figure 2–2: COMMUNICATION PATHS DIAGRAM
2.2.2 CHANNEL MONITOR
The L90 has logic to detect that the communications channel is deteriorating or has failed completely. This can provide an
alarm indication and disable the current differential protection. Note that a failure of the communications from the Master to
a Slave does not prevent the Ma st er f rom p erforming the curre nt differential algori thm ; failure of the comm uni ca tions from a
Slave to the Master w ill pr event the Master f rom pe rform in g th e c orr ect current diff erential logic. Cha nne l propagation dela y
is being continuo us ly mea sur ed a nd a dj usted according to chan ges in the communication s p ath. Every relay on the p r otec tion system can assigned an unique ID to prevent advertent loopbacks at multiplexed channels.
2.2.3 LOOPBACK TEST
This option allows the user to test the relay at one terminal of the line by “looping” the transmitter output to the receiver
input; at the same time, the signal sent to the remote will not change. A local loopback feature is included in the relay to
simplify single ended testing.
2.2.4 DIRECT TRANSFER TRIPPING
The L90 includes provis ion for s ending and rece iving a sin gle-po le Direct Transfer Trip (DTT) signa l from cur rent diff erentia l
protection between the L90 relays at the terminals of the line using the pilot communications channel. The user may also
initiate an additional 8 pilot signals with an L90 communications channel to create trip/block/signaling logic. A FlexLogic™
operand, an external contact closure, or a signal over the LAN communication channels can be assigned for that logic.
2-8 L90 Line Differential Relay
GE Power Management
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