Diagnostics of surge arresters using high voltage gradient ZnO elements for the 800 kV GIS by UHF partial discharge methods

It is important to perform partial discharge tests in order to evaluate the soundness of the insulation parts of surge arresters. Normally, surge arresters have been evaluated by ERA methods in factory tests. In this case, newly developed surge arresters for the 800 kV GIS using high voltage gradient ZnO elements have been diagnosed by UHF partial discharge methods. This paper describes test results of surge arresters for the 800 kV GIS by partial discharge tests.