8-4
L60 Line Phase Comparison System
GE Multilin
8.1 OVERVIEW
8 THEORY OF OPERATION
8
Figure 8–3: STABILITY ANGLE
Figures 8–4A, 8–4B, 8–4C, and 8–4D are for three-terminal lines and they correspond directly to Figures 8–2A, 8–2B, 8–
2C, and 8–2D. It will be noted from Figure 8–3 that for a three-terminal line, the relay at A must receive information from
both the remote terminals. The same applies to the relays at terminals B and C. As in the case of the two-terminal lines, the
integrator illustrated in Figure 8–4 will actually be set for 3 to 4 ms.
While all the sketches in Figures 8–2 and 8–4 compare the positive half cycle of current with a receiver output, the negative
half cycle might just as well have been selected. However, if this were done, in Figure 8–2A for example, it would have
been necessary to compare the presence of negative current with a received SPACE signal rather than a MARK signal.
It should be recognized that the above discussion, as well as Figures 8–1 and 8–2, are rudimentary. The complete phase
comparison scheme is considerably more sophisticated and will be discussed in more detail subsequently. However, at this
point it would be well to note that phase comparison on a continuous basis is not permitted mainly because it would tend to
reduce the security of the scheme. For this reason, fault detectors are provided. They initiate phase comparison only when
a fault occurs on, or in the general vicinity of, the protected line. A simplified sketch of the logic of a phase comparison
blocking scheme including fault detectors is illustrated in Figure 8–5. This is a somewhat more fully developed version of
Figure 8–2D, and the same logic is present at both ends of a two-terminal line.
83
17
2
4
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D
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Summary of Contents for UR series
Page 2: ......
Page 4: ......
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 ...