Optimal Coordination of Directional Overcurrent Relays for Fuse Saving in Distribution Networks With Distributed Generation

Ensuring the fuse remains intact during a fault is a key challenge in coordinating protection devices within distribution networks and microgrids. Coordinating protection becomes more complicated with the integration of distributed generations and different operating modes. To address the issue of undetected faults by the recloser in island mode, employing a pair of directional over-current relays on the lines could be a viable solution. Similarly, the fault current limiter is used to apply consistent settings for relay characteristics in various operating modes of the distribution network. In this paper, we want to optimize the value of fault current limiter and relays settings be set in such a way which the total operation time of the main and backup relays is minimized and the coordination between relay-relay and relay-fuse is maintained. To achieve this, genetic algorithm has been used to calculate the optimal value of relay settings and fault current limiter. The advantage of this design is avoiding mistakes in protection zones due to resistance or measurement errors. Moreover, eliminating the need for telecommunication system, and requiring single settings for relays compared to similar approaches is other remarkable advancement in this method.