Compactness and High-reliability Technology for UHV Circuit-breakers, disconnectors and earthing switches

摘要

UHV circuit breakers (CB) and other switchgears are the highest voltage rating and larger capacityequipment than other ratings, but applying reliable downsizing technology to UHV equipment will improvesuch advantage factors as environmental performance, safety and cost efficiency. Japanese utilities andmanufactures have been positively developing switchgear technologies of "high reliability" and "sizereduction". The keys for these technologies are suppressing various incidents of over voltage and findingways to reduce lightning and switching surges, which CBs generate surge voltage at current interruption ontransmission lines and disconnecting switches (DS's) generate very fast transient over voltage (VFTO) atswitching. Inserting suitable resistor in the switching process was studied and developed as a solution for thesurge voltage suppressing, and has been put to practical use in UHV switchgears. To ensure reliability ofpower system and its electricity, it is important to clear line fault and restore the system in short time. Highspeed grounding switch (HSGS) technology has been developed as the solution and able to provide highspeed re-closing on UHV system.These technologies have already been field-tested since 1996 in Japan and sufficiently validated. Sametechnologies are also being adopted to UHV system development in China, where the project is well underway. The high reliable downsizing technologies are expected to apply wider range of applications further.