An Accurate Off-line Fault Location Technique for DC Distribution System

DC system has been gaining an increasing attraction for many advantages when compared with AC counterpart. In order to remove the fault and restore the power supply as soon as possible, it is necessary to quickly and accurately locate the fault position. In this paper, an accurate off-line fault location method for DC distribution system is proposed. Firstly, the damped resonant frequency of probe voltage and current is almost independent of fault location by optimizing the parameters of probe power unit. Secondly, the equivalent inductance and resistance of the damped resonant circuit are calculated by adopting Least Square method. Thus, the fault position is obtained according to the established relation model between the equivalent resistance and the inductance of unit cable length. Finally, lots of simulation results under various kinds of fault conditions demonstrate the higher location accuracy, more reliable and stronger robustness of the proposed method.