Symmetrical fault current detector

Details Symmetrical fault current detector Symmetrical fault current detector

1986-04-21

1989-01-10

Pellinen, A. D.

Electricity: electrical systems and devices

Safety and protection of systems and devices

With specific current responsive fault sensor

361 87, H02H 3087

Patent

active

047977752

ABSTRACT:
Excess currents due to faults in an electrical power system are generally larger than excess currents due to the magnetization of distribution transformers. Discrimination has hitherto relied on a threshold detector. Magnetizing currents are, however, asymmetrical, whereas fault currents are symmetrical. A detector detects symmetrical current waveforms on a conductor 1 and thus discriminates between a fault and a magnetizing excess current. A resistor 4, placed across the output terminals of a bridge rectifier 3 has a resistance selected so that the voltage across it exceeds the breakdown voltage of trigger diodes 7 and 8 when the current in conductor 1, in any half cycle, exceeds a desired maximum. Capacitors 13 and 14 will thus only both charge up in response to an excessive symmetrical current. A logic control 23 is connected via lines 21 and 22 to detect such a condition.

REFERENCES:
patent: 3962606 (1976-06-01), Burns et al.
patent: 4454557 (1984-06-01), Hurley
patent: 4544980 (1985-10-01), Serrie et al.
patent: 4553188 (1985-11-01), Aubrey et al.
patent: 4583004 (1986-04-01), Yearsin

Affiliated with

Also associated with

Rating

Symmetrical fault current detector does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Symmetrical fault current detector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Symmetrical fault current detector will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2111436