Short circuit protection remains one of the major technical barriers in DC power systems. This paper introduces a new concept of ultrafast autonomous SSCBs. The new SSCB comprises one or more normally-on WBG transistor as the main static switch and a fast-starting isolated DC/DC converter as the protection driver. It detects short circuit faults by sensing its drain-source voltage rise, and draws power from the fault condition itself to turn and hold off the switch.
Prototypes experimentally demonstrate repeated interruption of fault currents up to 180 amperes at a DC bus voltage of 400 volts within 0.8 μs. A method to extend this concept to higher bus voltages is also proposed and verified with PSPICE simulation. A hybrid protection strategy, which combines protective power converters, autonomous SSCBs, and networked SSCBs, is proposed for shipboard DC power architectures.