Electricity: electrical systems and devices – Safety and protection of systems and devices – Feeder protection in distribution networks
Patent
1989-04-03
1990-06-19
DeBoer, Todd E.
Electricity: electrical systems and devices
Safety and protection of systems and devices
Feeder protection in distribution networks
361 66, H02H 308
Patent
active
049358375
ABSTRACT:
The square wave phase comparison signals generated for each phase of a power distribution system by phase comparison relays at each end of a protected three phase transmission line segment are combined to generate a single, multi-level signal with discrete values for each instantaneous combination of square wave signals. The single, multi-level signal is used to modulate a carrier signal which is transmitted over a single channel of a two-way communications link to the other terminal where the carrier signal is demodulated to reproduce the multi-level signal. The reproduced multi-level signal is then decoded to generate remote square wave signals which are compared with the phase of locally generated square wave signals to generate trip signals for circuit breakers at the respective terminals. Square waves representative of priority functions, such as direct transfer trips, can be integrated into the single, multi-level signal transmitted to the other terminal.
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Westinghouse, Technical Data 76-2, Effective 09/78 pp. 1-4, Westinghouse Electric Corporation, Relay-Instrument Division, Coral Springs, Fla.
Westinghouse I.L. 40-201.42, Instructions, Segregated Phase Comparison System Three Subsystems (A/B/C) Using DIT-4A Audio Tones, Effective Apr. 1979, Westinghouse Electric Corporation, Relay-Instrument Division, Coral Springs, Fla. pp. 1-30.
ABB Power T&D Company Inc.
Deboer Todd E.
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