Capacitor Commutation Method for MVDC Hybrid Circuit Breakers

• Main Author: Hyosung Kim
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Designs
• Subjects: medium voltage DC (MVDC); hybrid circuit breaker; conduction loss; arc; capacitor commutation
• Online Access: https://www.mdpi.com/2411-9660/5/2/28

The medium voltage DC (MVDC) type system can connect multiple terminals to a common MVDC bus, so it is possible to connect several renewable DC power sources to the common MVDC bus, but a DC circuit breaker is needed to isolate short circuit accidents that may occur in the MVDC bus. For this purpose, the concept of a hybrid DC circuit breaker that takes advantage of a low conduction loss contact type switch and an arcless-breaking semiconductor switch has been proposed. During break the hybrid switch, a dedicated current commutation device is required to temporarily bypass the load current flowing through the main switch into a semiconductor switch branch. Existing current commutation methods include a proactive method and a reverse current injection method by a LC (Inductor-capacitor) resonant circuit. This paper proposes a power circuit of a new MVDC hybrid circuit breaker using a low withstanding voltage capacitor branch for commutation and a sequence controller according to it, and verifies its operation through an experiment.