A Comparative Study on the Partial Discharge Characteristics of Dry-air and SF6

SF
6
gas has excellent insulation performance and has been widely used as the main insulating medium for Gas Insulated Switchgear (GIS). Unfortunately, since SF
6
gas has a very high Global Warming Potential (GWP), it generates a greenhouse effect. There is a growing interest in finding alterative gases to minimize the use of SF
6
gas. In this paper, the partial discharge (PD) characteristics of SF
6
and dry-air are compared to evaluate dry-air as an alternative gas that can replace SF
6
gas. PD measurements were performed for both SF
6
and dry-air using a prototype of 170kV eco-friendly GIS with non-uniform electric field which are designed to use dry-air as an insulation medium according to the eco-friendly GIS standard of KEPCO (GS-5925-0151), the main power utility in Korea. PD signals were measured for both SF
6
and dry-air by ultra-high frequency (UHF) sensors in order to check whether there is any difference in the received PD signal according to the difference of gas medium under the same condition. In this paper, the authors analyzed the sensitivity of PD signals to dry-air and SF
6
gas under the same conditions were analyzed, and furthermore, to verify through experiments whether the UHF PD sensor, which is widely used in SF
6
, can be applied to dry-air. The results provide a reference for practical application of the dry-air that can replace SF
6
gas in the power industry. It is expected that eco-friendly GIS filled with dry-air can be able to contribute for the rapid spread in the power network.