| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a device capable of resolving a problem of a ratio actuation relay provided in a circuit of a conventional transformer, and catching even an omen phenomenon of a transformer internal failure. <P>SOLUTION: Current transformers (CT) 5 and 6 are arranged in a primary side and a secondary side of a transformer 3, and a current which flows into said two current transformers is measured independently. Harmonics analysis is performed in each of circuits 11A and 11B, and a ratio of a higher order harmonic current to a fundamental-wave-frequency current is calculated using the detected data of the primary current and the secondary current. Then, a decision of a failure or insulation deterioration of a transformer is made to be possible on the basis of data calculated by a harmonic content ratio comparison circuit 19. <P>COPYRIGHT: (C)2012,JPO&INPIT |
