Discharge performance of conductor spikes in GIS under AC voltage

Gas insulated switchgear (GIS) is widely applied in power systems due to its excellent insulation performance. The reliability of GIS will be influenced by various insulation defects generated during the manufacture, installation, adjustment, operation and maintenance of the apparatus. Some defects, including conductor spikes, free metal particles, etc., make local electric field higher. Due to the HUMP effect of SF6 gas, the partial discharge inception voltage and the breakdown voltage of these defects are approximate to each other in non-uniform electric field under operating conditions. These defects cannot be effectively detected through partial discharge detection method as a result of this phenomenon. Different geometry of conductor spikes are used in this article, the partial discharge inception voltage and the breakdown voltage of these defects are measured by using ERA method, the results indicate that the breakdown performance is singular because of existence of space charge, and the partial discharge performance is closely related to the uniformity of gas gap.