Development of 800 kV gas-insulated switchgear

An 800 kV gas-insulated switchgear, with a capacity level recognized as the largest in the world, was developed as the first development of UHV gas-insulated switchgear, and good results were obtained in the type tests for this switchgear. With the gas circuit breaker and the disconnector used in this gas-insulated switchgear, tests on a scale innovative from a global viewpoint were carried out. Taking recent research into account, test methods were renovated. The long-term reliability of all insulators was demonstrated by submitting them to long-term voltage and current tests. Finally, measuring surges due to the switching of a disconnector and a shunt reactor on the equipment installed at the site, it was verified that measured and calculated values agreed