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L60 Line Phase Comparison System
GE Multilin
9.5 UNDERSTANDING L60 OSCILLOGRAPHY
9 APPLICATION OF SETTINGS
9
9.5.2 TWO BREAKER CONFIGURATION
The L60 has extra security when 2 CTs are brought into the relay individually and summed internally. Two currents are pro-
cessed separately to derive the operating signal for each breaker, which is then used for fault detectors and the forming of
positive and negative squares. This adds extra security for external faults beyond one of the breakers, with possible CT sat-
uration at the breaker carrying the full fault current from both the local and remote source as illustrated below.
Figure 9–11: BREAKER-AND-A-HALF SIGNAL PROCESSING
As shown in the oscillography, an external fault occurs on the breaker-and-a half diameter where the “F” CT/VT module is
fed from the Breaker 1 CT and the “M” CT/VT module is fed from the Breaker 2 CT. The positive and negative halves of the
waveform are opposite at two CTs. Operating in tripping mode, the L60 detects this condition and transmits only when pos-
itive samples from both CTs are present. As a result, the transmit signal is very small and does not allow remote operation.
In blocking mode, this fault would result in a continuous block signal sent to the remote relay. The separate processing of
currents is especially advantageous where fault currents are high and CT saturation is possible. Some times later, transient
blocking will recognize an external fault and operate blocking phase comparison until the fault current disappears.
831797A1.CDR
Summary of Contents for UR series
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Page 12: ...xii L60 Line Phase Comparison System GE Multilin TABLE OF CONTENTS ...
Page 32: ...1 20 L60 Line Phase Comparison System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 54: ...2 22 L60 Line Phase Comparison System GE Multilin 2 2 SPECIFICATIONS 2 PRODUCT DESCRIPTION 2 ...
Page 438: ...7 8 L60 Line Phase Comparison System GE Multilin 7 2 TARGETS 7 COMMANDS AND TARGETS 7 ...
Page 478: ...8 40 L60 Line Phase Comparison System GE Multilin 8 3 FAULT LOCATOR 8 THEORY OF OPERATION 8 ...
Page 502: ...A 10 L60 Line Phase Comparison System GE Multilin A 1 PARAMETER LIST APPENDIXA A ...
Page 584: ...B 82 L60 Line Phase Comparison System GE Multilin B 4 MEMORY MAPPING APPENDIXB B ...
Page 622: ...D 10 L60 Line Phase Comparison System GE Multilin D 1 PROTOCOL APPENDIXD D ...
Page 634: ...E 12 L60 Line Phase Comparison System GE Multilin E 2 DNP POINT LISTS APPENDIXE E ...
Page 642: ...F 8 L60 Line Phase Comparison System GE Multilin F 3 WARRANTY APPENDIXF F ...