A study of capacitive current switching capability by flashover characteristics between contacts of circuit breakers

This paper describes the capacitive current interruption capability of circuit breakers from the viewpoint of flashover characteristics between the contacts of breakers. The authors obtained flashover characteristics between the contacts having a short gap between them by comparing the data for new contacts and the data for contacts eroded after having been exposed to three interruptions at T60 according to amended regulations JEC 2300 (1998) and IEC 62271‐100 (2001). Comparison of the flashover characteristics and the electric field calculations obtained by measurements using new and eroded contacts have shown that the deterioration of dielectric strength amounts to 10 to 20%. The authors also conducted flashover tests for the contacts and nozzle after a significant number of interruptions. The total number of interruptions can be considered as the maximum possible number of interruptions according to CIGRE research. The deterioration of dielectric characteristics is 10 to 30%. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(1): 28–37, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10281