Historical review of high voltage switchgear developments in the 20th century for power transmission and distribution system in Japan

In Japan during the 20th century, developments of high voltage transmission and distribution apparatus advanced tremendously and circuit breakers were the center of these developments. And as a result, 1100 kV SF/sub 6/ gas insulated switchgear (GIS) for ac transmission systems and also 500 kV dc GIS for dc transmission systems have become available. Vacuum circuit breakers (VCBs) have also been actively developed and a 168 kV two break VCB and 100 kA VCB are already available. This paper describes these developments and future trends in technology.

I. Introduction

Following the invention of gas in 1900, the very high voltage insulating and large interrupting capabilities of gas circuit breakers (GCBs) were gradually understood, leading to significant advances in the latter half century. In Japan, compact, high voltage and high capacity substation equipment enclosed in was subjected to severe environmental contamination (particularly during the typhoon season), severe seismic problems and densely populated urban areas. GIS was suitable because all components could be installed at ground level. Also, because of the superb characteristics of the required capabilities for high capacity normal currents, insulating size and breaker interrupting could be obtained.