GE Multilin L60 Line Phase Comparison System ix
TABLE OF CONTENTS
8. THEORY OF OPERATION 8.1 OVERVIEW
8.1.1 INTRODUCTION................................................................................................ 8-1
8.1.2 FUNDAMENTAL PRINCIPLE OF PHASE COMPARISON ...............................8-1
8.1.3 VARIATIONS IN PHASE COMPARISON SCHEMES ....................................... 8-6
8.1.4 PHASE COMPARISON EXCITATION............................................................... 8-6
8.1.5 BLOCKING VS. TRIPPING SCHEMES........................................................... 8-10
8.1.6 SINGLE VS. DUAL PHASE COMPARISON.................................................... 8-18
8.1.7 REFINEMENTS TO BASIC SCHEMES...........................................................8-20
8.1.8 MULTI-TERMINAL LINES................................................................................8-23
8.1.9 CHARGING CURRENT COMPENSATION ..................................................... 8-23
8.1.10 L60 SIGNAL PROCESSING............................................................................ 8-25
8.2 SINGLE-POLE TRIPPING
8.2.1 OVERVIEW...................................................................................................... 8-33
8.2.2 PHASE SELECTION........................................................................................ 8-36
8.3 FAULT LOCATOR
8.3.1 FAULT TYPE DETERMINATION..................................................................... 8-37
9. APPLICATION OF
SETTINGS
9.1 PHASE COMPARISON ELEMENT 87PC
9.1.1 DESCRIPTION................................................................................................... 9-1
9.1.2 USE OF SETTINGS........................................................................................... 9-1
9.1.3 SETTINGS EXAMPLE ....................................................................................... 9-3
9.2 DISTANCE BACKUP/SUPERVISION
9.2.1 DESCRIPTION................................................................................................... 9-4
9.2.2 LINES WITH TAPPED TRANSFORMERS........................................................ 9-5
9.2.3 TRANSFORMER LOAD CURRENTS................................................................ 9-5
9.2.4 LV-SIDE FAULTS .............................................................................................. 9-5
9.2.5 TRANSFORMER INRUSH CURRENT .............................................................. 9-5
9.2.6 TRACTIONAL LOAD.......................................................................................... 9-6
9.2.7 SENSITIVITY ISSUES....................................................................................... 9-7
9.2.8 SINGLE-POLE TRIPPING APPLICATIONS...................................................... 9-8
9.2.9 PHASE DISTANCE............................................................................................ 9-9
9.2.10 GROUND DISTANCE......................................................................................9-10
9.3 POTT SIGNALING SCHEME
9.3.1 DESCRIPTION................................................................................................. 9-11
9.4 SERIES COMPENSATED LINES
9.4.1 DISTANCE SETTINGS.................................................................................... 9-12
9.5 UNDERSTANDING L60 OSCILLOGRAPHY
9.5.1 OVERVIEW...................................................................................................... 9-13
9.5.2 TWO BREAKER CONFIGURATION ............................................................... 9-14
A. FLEXANALOG
PARAMETERS
A.1 PARAMETER LIST
A.1.1 FLEXANALOG PARAMETERS .........................................................................A-1
B. MODBUS
COMMUNICATIONS
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-2
B.2 MODBUS FUNCTION CODES
B.2.1 SUPPORTED FUNCTION CODES ...................................................................B-3
B.2.2 READ ACTUAL VALUES OR SETTINGS (FUNCTION CODE 03/04H) ...........B-3
B.2.3 EXECUTE OPERATION (FUNCTION CODE 05H) ...........................................B-4
B.2.4 STORE SINGLE SETTING (FUNCTION CODE 06H).......................................B-4
B.2.5 STORE MULTIPLE SETTINGS (FUNCTION CODE 10H) ................................B-5