A Reliable Fuzzy Logic Controlled Power Converter Type Fault Current Limiter for Interconnected Power Systems

The recent advancement in the use of renewable energy resources and their interconnection to the main grid has increased the demand for high-rated protection devices. Because it is both technically and economically impossible to replace existing protection devices such as circuit breakers with higher ratings, the use of various types of Fault Current Limiters aids in limiting current and maintaining system reliability. A microgrid consists of various renewable energy sources and storage systems connected in an organized manner. One of the microgrid’s primary concerns is ensuring its safety, stability and reliability during fault occurrences. The system addressed here employs a Bridge type fault current limiter (FCL) controlled using fuzzy logic (FLC) to ensure efficient protection of the microgrid. The Fuzzy logic controller inserts an appropriate current limiting reactance during contingencies and removes it during normal conditions. Proposed system is tested virtually using MATLAB simulations using the WSCC 9 Bus test set up. Various fault conditions such as SLG, LL-G, and LLL-G with and without the proposed fuzzy controlled FCL system were compared and analyzed. Along with the fault studies the total harmonic distortion of the system was analyzed, and the results demonstrated that fault current can be maintained to acceptable limits with increased reliability of the system.