GE D90 Plus - Page 9

TABLE OF CONTENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL ix
Distance element time domain algorithm.................................................................................... 628
Distance element frequency domain algorithm........................................................................ 628
Distance supervision............................................................................................................................... 629
Distance characteristics........................................................................................................................ 630
Memory polarization............................................................................................................................... 636
Distance elements analysis................................................................................................................. 637
Phase distance applied to power transformers .................................................. 642
Example of system with power transformers............................................................................. 645
Ground directional overcurrent theory................................................................. 647
Ground directional overcurrent example ..................................................................................... 648
Series compensated lines ........................................................................................ 649
Memory polarized directional comparators................................................................................ 649
Dynamic reach control .......................................................................................................................... 650
Single-pole tripping................................................................................................... 652
SLG fault scenario for single-pole tripping ................................................................................... 654
SLG fault evolving into an LLG fault scenario for single-pole tripping ............................ 655
Phase selection.......................................................................................................................................... 656
Communications channels for pilot-aided schemes............................................................... 657
Permissive echo signaling.................................................................................................................... 664
Pilot scheme and phase selector coordination.......................................................................... 665
Cross-country fault example .............................................................................................................. 666
16 APPENDIX Warranty..................................................................................................................... 669
Revision history ......................................................................................................... 669