系统合环中工频变化量方向保护误动分析

Analysis about a misoperation of directional protection for power-frequency variable in connection of power system

针对某220kV线路在恢复送电过程中变电所侧RCS-901A纵联保护误动,根据线路两侧现场实测的故障录波波形和数据,判断出误动是由于发电厂侧收发信机的光电耦合器被击穿,导致收发信机一直处于听信状态。详细分析了RCS-901A型微机保护工频变化量方向纵联保护动作及保护装置在手合过程中工频变化量方向继电器工作原理,指出使用RCS-90lA型微机保护的线路,在线路送电过程中一定要保证收发信机和高频通道的正常工作,才能避免类似误动事故的再次发生。

RCS-901A longitudinal protection on the side of substation misoperated during the 220 kV line resumed transmission. According to waveform and data of fault recorder on two sides of the line, misoperation of relay protection is caused by the transceiver on the side of power plant being at the state of signaling-stop at all times, because of breakdown in its optocoupler. This paper analyses the directional protection of RCS-901A microcomputer for power-frequency variable and the theory about the operation of directional relay for power-frequency variable while the protector is manually engaged, and points out the occurrence of misoperation can be avoided only by ensuring normal operation of both transceiver and high-frequency channel while electric power is being transmitted in the power lines protected with RCS-901A microcomputer.