Analysis of the Maximum Electric Field for Changing Pressure using Breakdown Characteristic of $N_2+SF_6$, $N_2+CF_4$, $N_2$ Gases in a Cryogenic Environment

극저온 환경을 고려한 기압별 $N_2+SF_6$, $N_2+CF_4$, $N_2$가스의 절연파괴 전압 값을 이용한 최대전계 분석

High voltage cryogenic insulation issues need to be addressed in order to promote the commercialization of high temperature superconducting (HTS) equipment. As a fundamental step in the development of the optimum bushings for HTS devices, the breakdown characteristics of liquid nitrogen mixed with liquefied insulating gases such as $N_2$, $SF_6$, and $CF_4$ have been investigated. In order to investigate the possibility of substituting $CF_4$ gas for $SF_6$ gas for the bushings of HTS electrical equipment, AC withstanding voltage tests have been performed. In this paper, finding the maximum electric field $E_{max}$ using utilization factor ${\eta}$. This result is applicable to developing the real scale HTS equipment of the design parameters.