Failure modes and remedies of a solid-state low voltage DC circuit breaker through 3,000,000＋ operation cycles

This paper reports and analyzes the failure modes of a 1.2 kV low voltage (LV) solid-state dc circuit breaker (DCCB) over 3,000,000＋ opening operations. The motivation of this work is to study the assembly and component reliability of such a DCCB with real-world operational stress. To achieve the goal, accelerated DCCB operation tests are performed. After a comprehensive review of the test records and examination of the DCCB components, a total of five failure modes and three operational issues are identified. The natures of the failures and issues span from electrical design and mechanical structure to thermal management and cybersecurity. With each corresponding remedy being implemented, failures and issues are effectively addressed. To the best of the authors’ knowledge, this work is the first to publish results from DCCB that achieved 3,000,000＋ operations, providing meaningful references to improve solid-state DCCB design for LVDC applications.