Experimental Performance Validation of Z-Source DC Circuit Breaker for High Impedance Faults

Z-source DC circuit breakers (ZSCB's) provide automatic fault interruption without requiring sense and trip electronics. Further enables for rapid fault interruption with simple and less complex circuitry. However, the circuit breaker's minimum detectable fault ramp rate restricts the widespread use of ZSCBs. This limitation hinders the ZSCB's performance for protecting against high impedance short circuit faults and overload events. The effective solution of incorporating current sensors and an auxiliary branch with a power electronic switch has already been proposed in the literature. However, the proposed method has not been experimentally verified at higher system voltages and currents to validate the circuit breaker's performance. This paper describes the control strategy of the solution implemented with a modified Q-Z-Source circuit breaker (MQZSCB) and presents experimental results to support the circuit breaker's performance for high impedance faults considering more electric aircraft (MEA) standardized voltage rating of 270 V DC and at nominal current of 10 A with a preset fault current value of 20 A.