Electricity: electrical systems and devices – Safety and protection of systems and devices – With phase sequence network analyzer
Reexamination Certificate
2006-09-12
2006-09-12
Sircus, Brian (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
With phase sequence network analyzer
Reexamination Certificate
active
07106565
ABSTRACT:
A directional ground relay (50) for receiving electric values relating to voltage and current from a power transmission line (1) to be protected. The directional ground relay may decide a direction of a fault in the power transmission line based upon the electric values. The directional ground relay comprises a zero-phase sequential current calculation unit (10-2) for calculating a zero-phase sequential current based upon the current detected from the power transmission line. The directional ground relay further comprises a phase-comparison unit (10-3) configured to compare a phase of the zero-phase sequential current to a phase of voltage corresponding to the voltage in the power transmission line, to decide whether the zero-phase sequential current is within a pre-determined range, and to output the phase of the voltage as a faulty phase of voltage, when the zero-phase sequential current is within the pre-determined range.
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Electric Technology Research Association Report, vol. 37-1, no date.
Amo Hidenari
Kase Takahiro
Sonobe Yasutaka
Demakis James A.
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sircus Brian
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