Novel DC Hybrid Circuit Breaker with Self-charging Operation

With the rapid development of distributed power supply and the rapid growth of DC loads, DC distribution network has become the future development trend of power grid with its advantages of flexible control, high stability and high-power quality. As a key protection device, DC circuit breaker is of great significance for the safe and reliable operation of distribution network. However, the existing hybrid DC circuit breaker scheme in which the power electronic devices are subjected to large electro-thermal stresses in the hard-on transient increases the risk of device failure. In this paper, a hybrid DC circuit breaker scheme for low-voltage DC distribution networks is proposed, including the main branch, the power electronic branch and the active converter branch, which reduces the electro-thermal stress of the power electronic devices during the hard-on transient and improves the reliability of the circuit breaker, and the charging of the converter capacitor can be realized without complex switching operations. A simulation model is built to verify the operating characteristics of the proposed hybrid DC circuit breaker.