Reduction of Infeed Current Effects on Distance Relay by Optimal Sizing and Placement of Inductive Fault Current Limiters

The integration of Distributed Generation (DG) in Electric Power Networks altered the network behavior, particularly in power system protection. One such challenge is the infeed current effect, which distorts the impedance seen by distance relays, making them perceive a larger impedance than the actual fault location and potentially causing misoperation. This paper investigates the use of optimization algorithms - Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and Simulated Annealing (SA) - to size inductive Fault Current Limiters (FCLs) in the IEEE 9-bus system to mitigate infeed current effects. The optimized FCL placements were evaluated based on the measured relay impedance, comparing results with predefined Zone 3 settings and R-X plots from MATLAB, with validation from DIgSILENT PowerFactory. Results demonstrate that optimized FCL placement reduces impedance overestimation, improving fault detection accuracy for distance relays.