VOLTAGE BALANCE RELAY

PROBLEM TO BE SOLVED: To provide a voltage balance relay capable of improving a detection function.SOLUTION: A voltage balance relay body 120 detects unbalance between voltages VA and VB of systems A and B which are connected to a generator that is not shown in the figure, inputted from instrument transformers of the systems A and B but cannot detect the unbalance in the case where fuses of the same phase provided in first and second instrument transformers are simultaneously disconnected. Therefore, the detection function is complemented and improved by providing a fuse disconnection detection device 110. In the fuse disconnection detection device 110, first and second voltage comparators 5 and 6 issue signals S1 and S2 in the case where the voltages VA and VB become lower than a setting value VS, and first and second OR circuits 7 and 8 output a logical value 1 under the condition where an excitation signal SC of the generator that is not shown in the figure is present. If a state of the logical value 1 continues for a predetermined time, first and second circuit close delay timers 9 and 10 issue signals SX1 and SX2, and first and second relays 41 and 42 are excited. The signals SA and SB are outputted to the outside, and fuse disconnection is reported. 【課題】検出機能を向上させることができる電圧平衡継電器を得る。【解決手段】電圧平衡継電器本体１２０は、図示しない発電機に接続されたＡ系及びＢ系の計器用変圧器から入力されるＡ系及びＢ系の電圧ＶＡ，ＶＢの不平衡を検出するが、第一及び第二計器用変圧器に設けられた同相のヒューズが同時に断線したときは検出不能なので、ヒューズ断線検出装置１１０を設けて検出機能を補完し向上させる。ヒューズ断線検出装置１１０において、第一及び第二電圧比較器５，６は電圧ＶＡ，ＶＢが設定値ＶＳよりも低くなったとき信号Ｓ１，Ｓ２を発し、第一及び第二論理和回路７，８は図示しない発電機の励磁信号ＳＣの存在を条件に論理値１を出力し、論理値１の状態が所定時間継続すると第一及び第二閉路遅延タイマ９，１０が信号ＳＸ１，ＳＸ２を発し、第一及び第二継電器４１，４２を励磁し、外部に信号ＳＡ，ＳＢを出してヒューズ断線を報知する。【選択図】図１