GE L90 Instruction Manual page 8

10. APPLICATION OF
SETTINGS
viii
TABLE OF CONTENTS
9.3.4 MEMORY POLARIZATION ..............................................................................9-25
9.3.5 DISTANCE ELEMENTS ANALYSIS.................................................................9-26
9.4 PHASE DISTANCE APPLIED TO POWER TRANSFORMERS
9.4.1 DESCRIPTION .................................................................................................9-30
9.4.2 EXAMPLE .........................................................................................................9-32
9.5 SINGLE-POLE TRIPPING
9.5.1 OVERVIEW ......................................................................................................9-34
9.5.2 PHASE SELECTION ........................................................................................9-37
9.5.3 COMMUNICATIONS CHANNELS FOR PILOT-AIDED SCHEMES.................9-38
9.5.4 PERMISSIVE ECHO SIGNALING ....................................................................9-46
9.5.5 PILOT SCHEME / PHASE SELECTOR COORDINATION...............................9-47
9.5.6 CROSS-COUNTRY FAULT EXAMPLE............................................................9-48
9.6 FAULT LOCATOR
9.6.1 OVERVIEW ......................................................................................................9-49
9.6.2 MULTI-ENDED FAULT LOCATOR...................................................................9-49
9.6.3 SINGLE-ENDED FAULT LOCATOR ................................................................9-55
10.1 CT REQUIREMENTS
10.1.1 INTRODUCTION ..............................................................................................10-1
10.1.2 CALCULATION EXAMPLE 1............................................................................10-1
10.1.3 CALCULATION EXAMPLE 2............................................................................10-2
10.2 CURRENT DIFFERENTIAL (87L) SETTINGS
10.2.1 INTRODUCTION ..............................................................................................10-3
10.2.2 CURRENT DIFFERENTIAL PICKUP ...............................................................10-3
10.2.3 CURRENT DIFF RESTRAINT 1 .......................................................................10-3
10.2.4 CURRENT DIFF RESTRAINT 2 .......................................................................10-3
10.2.5 CURRENT DIFF BREAK POINT ......................................................................10-3
10.2.6 CT TAP .............................................................................................................10-4
10.2.7 BREAKER-AND-A-HALF ..................................................................................10-6
10.2.8 DISTRIBUTED BUS PROTECTION .................................................................10-9
10.3 CHANNEL ASYMMETRY COMPENSATION USING GPS
10.3.1 DESCRIPTION ...............................................................................................10-10
10.3.2 COMPENSATION METHOD 1 .......................................................................10-10
10.3.3 COMPENSATION METHOD 2 .......................................................................10-11
10.3.4 COMPENSATION METHOD 3 .......................................................................10-11
10.4 DISTANCE BACKUP/SUPERVISION
10.4.1 DESCRIPTION ...............................................................................................10-13
10.4.2 PHASE DISTANCE ........................................................................................10-14
10.4.3 GROUND DISTANCE.....................................................................................10-15
10.5 PROTECTION SIGNALING SCHEMES
10.5.1 OVERVIEW ....................................................................................................10-17
10.5.2 DIRECT UNDER-REACHING TRANSFER TRIP (DUTT) ..............................10-17
10.5.3 PERMISSIVE UNDER-REACHING TRANSFER TRIP (PUTT)......................10-17
10.5.4 PERMISSIVE OVER-REACHING TRANSFER TRIP (POTT) ........................10-17
10.5.5 HYBRID POTT SCHEME (HYB-POTT)..........................................................10-18
10.5.6 DIRECTIONAL COMPARISON BLOCKING...................................................10-19
10.5.7 DIRECTIONAL COMPARISON UNBLOCKING .............................................10-20
10.6 SERIES COMPENSATED LINES
10.6.1 DISTANCE SETTINGS ON SERIES COMPENSATED LINES ......................10-22
10.6.2 GROUND DIRECTIONAL OVERCURRENT ..................................................10-23
10.7 LINES WITH TAPPED TRANSFORMERS
10.7.1 DESCRIPTION ...............................................................................................10-24
10.7.2 TRANSFORMER LOAD CURRENTS ............................................................10-24
10.7.3 LV-SIDE FAULTS ...........................................................................................10-25
10.7.4 EXTERNAL GROUND FAULTS .....................................................................10-25
10.8 INSTANTANEOUS ELEMENTS
10.8.1 INSTANTANEOUS ELEMENT ERROR DURING L90 SYNCHRONIZATION ...10-
26
L90 Line Current Differential System GE Multilin