Electricity: electrical systems and devices – Safety and protection of systems and devices – With specific quantity comparison means
Patent
1986-04-10
1987-11-10
Pellinen, A. D.
Electricity: electrical systems and devices
Safety and protection of systems and devices
With specific quantity comparison means
361 65, H02H 326
Patent
active
047061561
ABSTRACT:
A distance relay, for indicating single phase to ground faults on a polyphase electric power transmission system, having guard zone comparators (17,18,19) generating a first guard zone quadrilateral characteristic (21,23,25,27) in respect of each phase of the system and additional comparators (43,45,47) cooperating with the guard zone comparators (17,18,19) for generating a second main quadrilateral characteristic (23,25,27,49) in respect of each phase of the system, and a logic circuit arrangement (31 to 41) whereby the relay indicates the presence of a fault on a single phase to ground within the reach of the main characteristic relating to the relevant phase only if the corresponding guard zone characteristic, and no other, indicates a fault. The slope of the reactance line (21) of each guard zone characteristic is arranged to change its slope under two-phase phase to earth fault conditions by a lesser amount than the reactance line (49) of the corresponding main characteristic. By using the comparators false operation of the relay due to changes in slope of the reactance lines of the characteristics under two-phase to ground fault conditions is avoided.
REFERENCES:
patent: 4293886 (1981-10-01), Church et al.
patent: 4377833 (1983-03-01), Udren
patent: 4405966 (1983-09-01), Cavero
patent: 4433353 (1984-02-01), Wilkinson
Jennings Derek S.
Pellinen A. D.
The General Electric Company p.l.c.
LandOfFree
Protection apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Protection apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Protection apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1071693