| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that, in a conventional protective relay system, when a current differential protective relay device that is a master station to be a reference of a sampling time is separated from a transmission network, until all current differential protective relay devices of slave stations establish time synchronism with a current differential protective relay device that is a next master station candidate to newly become the master station, the current differential protective relay devices in the protective relay system fall into a locked state and during that, the protective relay system may lose a protective function.SOLUTION: A master station comprises a separation request processing part 104 which transmits a separation request. A separation permission discrimination part 106 is provided by which, if there is a separation request from the master station to slave stations, it is confirmed beforehand that all the slave stations can be temporally synchronized with the next master station candidate, and a separation permission is transmitted. A master-slave station switching processing part 105 is provided for confirming the separation permissions of all the slave stations and outputting a master station switching command.SELECTED DRAWING: Figure 2 |
