Effects of multiple interruptions on post‐arc current,reignition, and lifetime of distribution breaker

The purpose of this investigation is to study the interruption performance of the Molded Case Circuit Breaker (MCCB) currently used for the protection of low‐voltage circuits. It is anticipated that interruptions, especially numerous high‐current interruptions, will degrade interruption performance. In order to investigate the performance change after many interruptions, it is important to understand the interruption characteristics. Multiple‐interruption experiments at large currents were conducted and the phenomena which govern the success or failure of interruption were identified. It was shown that after multiple interruptions a post‐arc current begins to flow and that the duration of the arc is ten to a few hundred microseconds. In order to explore the relationship between the post‐arc current and the degradation of the interruption characteristics, the conditions governing the post‐arc current were investigated experimentally. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(4): 42–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10358