Development of an Efficient Solid-State Fault Current Limiter for Microgrid

This paper deals with the development of a resonant-type solid-state fault current limiter (SSFCL), suitable for distribution-generation (DG) units in the microgrid. The proposed SSFCL has both series and parallel resonant circuits that are tuned at the supply frequency. In normal condition, the SSFCL exhibits very low impedance through the series resonant circuit. In fault conditions, the SSFCL offers very high impedance by the parallel resonant circuit. Upon fault occurrence, an auto-triggered silicon control rectifier (SCR) inserts the parallel resonant circuit in the load current path. In addition to self-controlling capability of the proposed SSFCL, it can be controlled using an external command generated by a fault detection algorithm. Therefore, with a very simple structure, it provides adequate certainty of operation. A prototype single-phase SSFCL is simulated in the Electromagnetic Transient Program (EMTP) and tested. The results show that the proposed SSFCL can significantly reduce the fault current in a short time.