A hybrid protection scheme to mitigate the effect of distributed generation on relay coordination in distribution system

Increasing penetration level of distributed power generation in distribution system causes failure of existing non-directional and directional overcurrent relay coordination. A hybrid protection schemes based on application of fault current limiter and microprocessor based overcurrent relays is advised to eliminate the impact of distributed generation on distribution system relay coordination. The covariance matrix adaptation evolution strategy directed target to best perturbation based algorithm is applied for optimizing the setting of overcurrent relays. The performance the proposed algorithm is quite satisfactory as compared to other heuristic and met- heuristic based optimization algorithm. The proposed protection scheme requires minimum number of relay replacement and small size fault current limiter to mitigate the impact of distributed generation impact in the distribution system. The proposed protection scheme is simulated in MATLAB and tested on IEEE 30 bus distribution system.