| 摘要 |
PROBLEM TO BE SOLVED: To constitute a protection relay system which can commonly use an input converter for mainly detecting and detecting an accident of the protection relay system using a current variation width relay for protecting a power system by detecting an accident current. SOLUTION: The protection relay system includes a short-circuit distance relay element to be input by a current signal and a voltage signal, and a short-circuit overcurrent relay element to be input by the current signal. Further, the system has a main detecting element for outputting the operation signal when both the short-circuit distance relay element, the short-circuit overcurrent relay element, and the current variation relay element which operates when a current value of the current signal exceeds a predetermined variation width. A drawing-out command signal is output to the accident detecting element for preventing an output by mistake from the system when the main detecting element is operated by mistake, and a circuit breaker to be controlled when the main detecting element and the accident detecting element are operated. The current variation width relay element uses the current variation width relay only when the current signal is changed to be increased. COPYRIGHT: (C)2004,JPO
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