Lightning Impulse Breakdown Characteristics of N_2 Gas under Quasi-Uniform Electric Field

摘要

This paper describes the breakdown characteristics of lightning impulse for N_2 under a quasi-uniform electric field in high gas pressure. The breakdown voltages of Weibull plots had the same characteristics curve in both of positive and negative polarities between 0.4 and 0.7 MPa. The breakdown voltages of Weibull plots of positive polarity in N_2 were more distribute than those of negative polarity. The breakdown voltage was decreased when electrode area increased in both positive and negative polarities. The breakdown voltage V_(0.1% ) whose breakdown probability is 0.1% by location parameter as zero was increased as gas pressure increased. V_(0.1% )of positive polarity was about 25% lower than that of negative polarity. On the other hand, the breakdown voltage for breakdown probability of 50% of positive polarity was the same as that of negative polarity. To discuss minimum breakdown voltages, the authers attempted to obtaine minimum breakdown voltage based on location parameter V_(min). Because approximate curves of Weibull plots of positive polarity for N_2 do not have location parameter, V_(0.1% ) was define as minimum breakdown volatge, and it was lower than V_(min) of negative polarity. In addition, the normalized value by theoretical breakdown strength in positive polarity for N_2 was lower than V_(min) of negative polarity for N_2, Dry-Air, and SF_6.