Document Type and Number:
Japanese Patent JPH01502299
Kind Code:
A
Abstract:
A system and method is disclosed for detecting an abnormality in a network for distributing or transmitting electric power at a predetermined fundamental frequency. The system produces a signal representing the fundamental frequency and another signal representing a harmonic current occurring in the network. The phasor relation between the fundamental voltage and harmonic current representing signal are compared. The system produces a signal indicating the occurrence of a high impedance fault in response to a predetermined change in the compared phasor relationship. Embodiments are disclosed utilizing expression of signals within the network in polar coordinates, as well as embodiments utilizing signals expressed in rectangular coordinates. Such embodiments include circuitry for detecting zero crossing phenomena, as well as circuitry for producing representation of signal products.
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Application Number:
JP50226888A
Publication Date:
August 10, 1989
Filing Date:
January 15, 1988
Export Citation:
International Classes:
G01R31/02; G01R25/00; G01R31/08; H02H1/00; H02H3/00; H02H3/38; (IPC1-7): G01R25/00; G01R31/02; G01R31/08; H02H3/00; H02H3/38