Impulse, Switching Surge, and 60-Hz Sparkover Tests by Three Laboratories on a 500-kY Ring-to-Rod Protective Gap

The objective is to promote a better understanding of protective gaps, their characteristics, influence of design factors on perfornance, applications, and limitations. Accordingly, the Working Group sponsored sparkover tests on a proposed 500-kV ring-to-rod protective gap. Comparative tests were conducted at laboratories of the Ohio Brass Company, the Hydro-Electric Power Commission of Ontario, and the Bonneville Power Administration. This paper summarizes and compares the impulse, switching surge, and 60-Hz sparkover test results.