A fast scheme for fault detection in DC microgrid based on voltage prediction

Abstract

Protection schemes for AC transmission systems are well understood and matured. On the other hand, developing proper protection scheme for DC system is still a research challenge. A distributed fault detection and localization scheme, based on local measurements, is proposed in this paper. It is based on the fact that a fault generally leads to a significant drop in the voltage along with its high rate of change. The voltage at the fault point is predicted using a quadratic time varying function. In case of fault, the difference in the predicted and the true values exceeds certain threshold. A systematic procedure for setting the necessary threshold value is also suggested. The protection system has been modelled and tested for different fault types, their locations. and with the noisy measurement. The proposed scheme is validated on a ring type DC microgrid system using Real Time Digital Simulator (RTDS).