PROTECTION RELAY DEVICE, ELECTRIC POWER SYSTEM PROTECTION SYSTEM, AND ELECTRIC POWER SYSTEM PROTECTION METHOD

PROBLEM TO BE SOLVED: To detect a fault current even when the accidental current exhibits a low current value.SOLUTION: An electric power system 1 includes a power-plant-side circuit GS having a parallel breaker 2a, a power-receiving-line-side circuit 1S having a power-transmitting-line breaker 2b, and a power-receiving-line-side circuit 2S having a power-transmitting-line breaker 2c. The power-plant-side circuit GS has an AVR 4 and a governor 5 and is measured by a measuring device 6a. The power-receiving-line-side circuits 1S and 2S have measuring devices 6b and 6c, respectively, and are measured for the current value and the direction thereof. The electric power system 1 includes a protection relay device 10 having a receiving section 11, a determination and processing section 12, and a breaker operation section 13. The determination and processing section 12 determines whether an accident is caused in a power transmitting line based on electric power system information E comprising measurement results of the measuring devices 6a, 6b and 6c, for example, and determines whether the parallel breaker 2a and the power-transmitting-line breakers 2b and 2c are to be switched on/off. Thus, a fault current can be detected even when the accidental current exhibits a low current value.SELECTED DRAWING: Figure 1 【課題】事故電流の電流値が微小であっても故障電流を検知することを可能にする。【解決手段】電力系統１には、発電所側回路ＧＳに並列用遮断器２ａが、受電線側回路１Ｓに送電線遮断器２ｂが、受電線側回路２Ｓに送電線遮断器２ｃが設けられ、発電所側回路ＧＳにはＡＶＲ４及び調速機５が設けられて計測装置６ａにより計測され、受電線側回路１Ｓ，２Ｓには計測装置６ｂ，６ｃが設けられて電流値とその向きが計測されている。この電力系統１には、保護継電装置１０が設けられ、保護継電装置１０は受信部１１と、判断処理部１２と、遮断器操作部１３とを備えている。判断処理部１２は、計測装置６ａ，６ｂ，６ｃの計測結果等から構成されている電力系統情報Ｅに基づいて、送電線の事故の有無を判断し、並列用遮断器２ａ及び送電線遮断器２ｂ，２ｃの入／切を判断する。これにより、事故電流の電流値が微小であっても故障電流を検知することが可能になる。【選択図】 図１