Modular Hybrid DC Circuit Breaker for Medium-Voltage DC System

Abstract

This paper proposes a new modular hybrid DC Circuit Breaker (DCCB) for Medium-Voltage DC (MVDC) grid system. The proposed DCCB has mechanical switch which is composed of Vacuum Interrupter (VI) and Permanent Magnetic Actuator (PMA). And commutation path which is composed of two IGBTs and diodes is connected to the VI in parallel. The proposed DCCB can operate protection coordination of DC grid through the open/close operation of PMA. To interrupt the DC fault current, PMA driver circuit was designed to separate the VI in a few milliseconds. The proposed DCCB has a simple design and ensures the modularization to deal with high voltage level. Experimental results in reduced scale have demonstrated the breaking performance and black-box model was also investigated for the feasibility of modularization.