A Communication-free Fault Detection and Classification Scheme for Industrial Microgrids

Abstract

The fault detection and classification (FDAC) of the islanded industrial microgrids is challenging due to the low short circuit current from inverter based sources and the bidirectional nature of current. This article proposes a FDAC scheme, which utilizes the local voltage at the relays, placed at both sides of the line section. The relays can be programmed to adapt to the proposed scheme, and hence there is no need for additional communication. The transient monitoring function (TMF) of the voltage signal (Tv) is calculated, which gives the information of the fault transients. Compared to its pre-fault value, the faulty phase Tv significantly reduces during a fault. Therefore, the Tv of any phase less than a pre-defined threshold (Tth) confirms the occurrence of a faulty event and respective faulty phases. The nature of the Tv is studied with extensive simulations to decide the suitable Tth• The proposed scheme is validated on the modified CIGRE test microgrid for all eleven types of shunt faults. Several test cases are simulated in MATLAB Simulink at various locations with different inception angles, loading conditions, and fault resistances. The obtained results are found to be satisfactory for FDAC, with local information available at relaying points.