Controlled power sequencing for fault protection in DC nanogrids

Abstract

For dc power distribution systems, we show how coordinated operation of electronic power converters and mechanical contactors (segmentizing switches) can permit rapid response to short circuit faults. It is possible to de-power the dc bus, open a contactor to isolate the faulted branch, then restore power to the remaining branches in less than 8 ms, so that the remaining loads can ride through the entire operation. This is faster than can typically be achieved in ac power networks using conventional technologies. Clamping diodes and point of load capacitors improve system robustness. Our results provide a detailed analysis, design guidelines, and explain how the protection scheme responds to different configuration of the system.