Electricity: electrical systems and devices – Safety and protection of systems and devices – With tuned circuit
Patent
1989-05-09
1990-02-20
Deboer, Todd E.
Electricity: electrical systems and devices
Safety and protection of systems and devices
With tuned circuit
361 85, 361 87, H02H 346
Patent
active
049031635
ABSTRACT:
A single or multiple phase directional harmonic overcurrent relay device suitable for simultaneously monitoring overcurrents at either of two harmonic frequencies in an electric power system is provided which comprises current and voltage input means, upper and lower harmonic current and voltage filters, a trip means which can enable an appropriate protective or diagnostic device when a condition of harmonic overcurrent exists, and a phase detection means which receives signals from the voltage and current filters and transmits a signal to the trip means only when the phase angle between the harmonic voltage and harmonic current is within a specified range. The two harmonics that are to be monitored simultaneously, such as the 5th and 7th harmonics, can be selected by means of a series of simple filter cards which can be inserted into a card cage in an apparatus housing the relay of the present invention. The relay of the present invention also employs adjustable taps for conveniently setting the minimum level of harmonic current corresponding to a condition of overcurrent, and provides a selection of time-overcurrent characteristic operating curves to delay the operation of the trip means once a condition of harmonic overcurrent has been detected. The relay is advantageous in that extremely low levels of harmonic overcurrent can be monitored so as to or prevent damage to a power system, and in that two harmonic currents may be monitored simultaneously.
REFERENCES:
patent: 4196463 (1980-04-01), Dickerson
patent: 4208687 (1980-06-01), Sun et al.
patent: 4477854 (1984-10-01), Usui et al.
patent: 4513344 (1985-04-01), Usui
Atwater Philip L.
Jacobs Malin L.
Deboer Todd E.
Koltos E. Philip
The United States of America as represented by the Secretary of
LandOfFree
Directional harmonic overcurrent relay device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Directional harmonic overcurrent relay device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Directional harmonic overcurrent relay device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1620836