A hybrid algorithm for fault locating in looped microgrids

Abstract

Protection is the last obstacle to realizing the idea of microgrid. Some of the main challenges in microgrid protection include topology changes of microgrid, week-infeed fault, bidirectional power flow effects, blinding of the protection, sympathetic tripping, high impedance fault, and low voltage ride through (LVRT). Besides these challenges, it is desired to eliminate the relays for distribution lines and locate faults based on distributed generations (DGs) voltage or current. On the other hands increasing in the number of DGs and lines would result in high computation burden and degradation the efficiency and accuracy of the methods that utilize all these information. This paper deals with this issue by analyzing only DGs' voltage. In the first step, a fault is detected by the voltage of each DG, then the DG with the highest voltage collapse injects 333 Hz harmonic to find another DG that the fault occurs within them. Two criteria are defined in such a way to prevent injection of voltage harmonic by the other DGs. Finally, the fault is located in the reduced space of search by wavelet transform and optimized multiclass support vector machine (M-SVM). In the simulation results, the contribution of this method is shown and results also validate the efficiency of the proposed method.