GE L30 Instruction Manual page 8

8 APPLICATION OF
SETTINGS
9 COMMISSIONING
10 THEORY OF
OPERATION
viii
8.1 CT requirements .............................................................................................. 8-1
8.1.1 Introduction .............................................................................................................................8-1
8.1.2 CT saturation analysis tool ...............................................................................................8-2
8.2 Current differential (87L) settings ................................................................ 8-3
8.2.1 Introduction .............................................................................................................................8-3
8.2.2 Current differential pickup................................................................................................8-4
8.2.3 Current differential restraint 1 ........................................................................................8-4
8.2.4 Current differential restraint 2 ........................................................................................8-4
8.2.5 Current differential break point......................................................................................8-4
8.2.6 CT tap..........................................................................................................................................8-4
8.3 Channel asymmetry compensation using GPS .......................................... 8-6
8.3.1 Introduction .............................................................................................................................8-6
8.3.2 Compensation method 1...................................................................................................8-6
8.3.3 Compensation method 2...................................................................................................8-7
8.3.4 Compensation method 3...................................................................................................8-8
8.4 Instantaneous elements................................................................................. 8-9
8.4.1 Instantaneous element error during L30 synchronization................................8-9
9.1 Testing ............................................................................................................... 9-1
9.1.1 Channel testing......................................................................................................................9-1
9.1.2 Clock synchronization tests .............................................................................................9-2
9.1.3 Current differential ...............................................................................................................9-3
9.1.4 Local-remote relay tests....................................................................................................9-4
10.1 Overview .........................................................................................................10-1
10.1.1 L30 design ............................................................................................................................. 10-1
10.1.2 L30 architecture .................................................................................................................10-2
10.1.3 Removal of decaying offset .......................................................................................... 10-2
10.1.4 Phaselet computation ..................................................................................................... 10-2
10.1.5 Disturbance detection ..................................................................................................... 10-3
10.1.6 Fault detection .................................................................................................................... 10-3
10.1.7 Ground differential element.......................................................................................... 10-5
10.1.8 Clock synchronization...................................................................................................... 10-6
10.1.9 Frequency tracking and phase locking ................................................................... 10-6
10.1.10 Frequency detection......................................................................................................... 10-7
10.1.11 Phase detection.................................................................................................................. 10-8
10.1.12 Phase-locking filter......................................................................................................... 10-10
10.1.13 Matching phaselets........................................................................................................ 10-11
10.1.14 Start-up................................................................................................................................ 10-12
10.1.15 Hardware and communication requirements .................................................. 10-12
10.1.16 Online estimate of measurement errors.............................................................. 10-12
10.1.17 CT saturation detection................................................................................................ 10-13
10.1.18 Charging current compensation ............................................................................. 10-14
10.1.19 Differential element characteristics....................................................................... 10-15
10.1.20 Relay synchronization................................................................................................... 10-16
10.2 Operating condition characteristics........................................................10-17
10.2.1 Description ......................................................................................................................... 10-17
10.2.2 Trip decision example ................................................................................................... 10-19
10.2.3 Trip decision test ............................................................................................................. 10-19
10.3 Fault locator .................................................................................................10-20
10.3.1 Description ......................................................................................................................... 10-20
L30 LINE CURRENT DIFFERENTIAL SYSTEM - INSTRUCTION MANUAL
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