Self Powered Low Voltage DC Circuit Breaker

Short circuit protection remains one of the major technical barriers in DC power system because of the high rate of rise of fault currents and the absence of current zeros. Circuit breaker based on power semiconductor devices have the potential of fast interruption of fault currents. The paper analyses the performance of various solid state circuit breakers. Wideband devices such as silicon carbide offers better performance than silicon devices in terms of on-state conduction loss, faster fault clearing time and higher temperature handling capability. Among the SiC device normally on JFET has better performance than SiC BJT and SiC MOSFET, in terms of avalanche and short circuit rating. A self powered normally-on circuit breaker was analyzed and designed. The overload protection feature which is essential for a circuit breaker was incorporated. Experimental tests were conducted to verify the performance of the breaker under overload and short circuit conditions. The results shows that the breaker operation is completed in 17 microseconds and the recovery voltages rises to 520 V. The designed breaker is capable of interrupting short circuit current at 27 A.