PURPOSE: To enable the reclosing time to be equivalent as before and to execute a high-speed multi-phase reclosing while maintaining stability even if a system voltage is high by speedily grounding a fault breaking phase after the transmission line fails and is broken and readily extinguishing secondary arc current.
CONSTITUTION: When a fault occurs at a point F, a fault current flows through a transmission line 1, thus operating flow transmission line protection relay devices 10 and 11, breaking circuit breakers 2a and 3a, and activating reclosing. Then, circuit breakers 12a and 13a for grounding are thrown and an accident break phase is forced to be grounded, thus readily extinguishing secondary arc current. By speedily grounding the fault breaking phase with the circuit breakers 12a and 13a for grounding, the reclosing time can be made equivalent to a conventional level even in a UHV system and stably and speedily performing multiple-phase reclosing.
SHIRATA YOSHIHIRO
YOSHIDA MASAYUKI
UENO KAZUO
HORI MASAO
KUDO KAZUHIKO
TOSHIBA CORP