Determination of optimum resistance for resistive fault current limiter for protection of a power system with distributed generation

When a distributed generator (DG) is connected to a system and if a fault occurs, it acts as a source of fault current. Original relay protection scheme is affected by the connection of distributed generators (DG) and causes mal-operation of both primary and backup relays. The fault current contribution of DG can be limited by placing fault current limiter (FCL) in series with the DG. This paper proposes a novel method for the determination of the optimum resistance value for the FCL and thus to retain the original settings of relays. For optimizing the value of resistance of resistive fault current limiter Genetic Algorithm (GA) is used and the original relay settings are restored. The effectiveness of proposed method in the presence of single and multiple DG existence is also illustrated.