| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a malfunction prevention device for a protective relay which can prevent a malfunction of the protective relay without using a zero-phase-sequence current transformer, and which is not necessary to be enlarged in its size. <P>SOLUTION: A malfunction prevention device for a protective relay according to this invention operates based on a current flowing in a common circuit connected commonly to output circuits of a plurality of current transformers which set an electric circuit of each phase of a three-phase AC electric circuit as a primary conductor. The electric circuit of each phase is configured so as to be grounded via a grounding switch at the time of transmission stop. The device comprises a switching means that drives the grounding switch based on the operation in which the grounding is performed, and shorts the output circuits of the plurality of current transformers and cuts off at least either of the output circuits of the plurality of current transformers or the common circuit. <P>COPYRIGHT: (C)2012,JPO&INPIT |
