Evaluation of overvoltage protection requirements for a DC UAV electrical network

This paper analyses the behaviour of a highly-capacitive DC UAV network under fault conditions. Through simulation, the nature of overvoltage transients caused by the redistribution of stored energy following the clearance of a fault is illustrated. It is found that clearance of fault currents at or around their peak magnitude can result in substantial quantities of inductive energy being redirected into the smaller load capacitors, causing severe overvoltages across these loads. Recommendations for a protection strategy are given on the basis of the results presented, with consideration given to the use of surge arrestors to provide additional overvoltage protection to sensitive loads.