Reliability of epoxy spacer for EHV-class gas insulated switchgear

We describe two different results obtained in the development of several types of spacer for GIS. Firstly, for the three-phase spacer of 362 kV GIS, we present the optimal design that was obtained by electric field analysis and mechanical stress analysis using commercial program, respectively. We also report the results of reference test in our factory after manufacturing process. Secondly, the spacer installed in 800 kV GIS that has the highest voltage of power system in Korea, was performed the accelerated deterioration test because this spacer requires high reliability during operation period of power apparatus. This test was carried out during seven months after finishing the type test. In order to confirm the electrical lifetime for epoxy spacer, an equivalent test method was applied at higher voltage than the operating voltage (800/√3=462 kV rms). After that test, we proved the reliability of the spacer through electrical insulation test equal to the type test. From these results, it can be seen that the epoxy spacer had a lifetime guarantee of more than 30 years