GE L90

L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL iii
L90 Line Current Differential System
Table of contents
1INTRODUCTION 1.1 Safety symbols and definitions ........................................................................... 1-1
1.1.1 General cautions and warnings .................................................................................... 1-1
1.2 For further assistance........................................................................................... 1-2
2PRODUCT
DESCRIPTION
2.1 Product description ............................................................................................... 2-1
2.1.1 Features.................................................................................................................................... 2-3
2.2 Pilot channel relaying............................................................................................ 2-5
2.2.1 Inter-relay communications............................................................................................ 2-5
2.2.2 Channel monitor................................................................................................................... 2-7
2.2.3 Loopback test......................................................................................................................... 2-7
2.2.4 Direct transfer tripping ...................................................................................................... 2-8
2.3 Security .................................................................................................................... 2-8
2.4 Order codes...........................................................................................................2-11
2.4.1 Order codes with enhanced CT/VT modules.........................................................2-12
2.4.2 Order codes with process bus modules ..................................................................2-19
2.4.3 Replacement modules.....................................................................................................2-26
2.5 Signal processing................................................................................................. 2-28
2.5.1 UR signal processing ........................................................................................................2-28
2.6 Specifications........................................................................................................ 2-30
2.6.1 Protection elements..........................................................................................................2-31
2.6.2 User-programmable elements ....................................................................................2-40
2.6.3 Monitoring..............................................................................................................................2-42
2.6.4 Metering..................................................................................................................................2-43
2.6.5 Inputs .......................................................................................................................................2-44
2.6.6 Power supply........................................................................................................................2-45
2.6.7 Outputs....................................................................................................................................2-46
2.6.8 Communication protocols..............................................................................................2-48
2.6.9 Inter-relay communications..........................................................................................2-49
2.6.10 CyberSentry security.........................................................................................................2-50
2.6.11 Graphical front panel........................................................................................................2-50
2.6.12 Environmental......................................................................................................................2-51
2.6.13 Type tests...............................................................................................................................2-52
2.6.14 Production tests..................................................................................................................2-52
2.6.15 Approvals ...............................................................................................................................2-53
2.6.16 Maintenance.........................................................................................................................2-53