DEVELOPMENT OF 800KV GAS-INSULATED SWITCHGEAR

Because of the growing demand for electricity in large cities, where the construction of electric power generation stations is difficult, transmission voltages have been rising for achieving large-capacity transmission efficiency. Replying to this tendency, we developed an 800kV gas-insulated switchgear, with a capacity level recognized as the largest in the world, as the first development of UHV gas-insulated switchgear, and we obtained good results in the type tests of this new switchgear. With the gas circuit breaker and the disconnector, in particular, used in this gas-insulated switchgear, we carried out tests on a scale innovative from a global viewpoint. Taking recent research into account, we also renovated test methods. We proved the long-term reliability of all insulators 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, we verified that measured and calculated values agreed.