A novel protection strategy for distribution systems with distributed generation

In this paper, a new strategy is proposed to provide a solution to the recloser–fuse coordination problem that appears after distributed generation penetration in distribution systems. The core of this strategy is based on classifying the coordination status at fault conditions to either coordination holds or coordination lost. The main benefit from this classification process is to indicate if the existing protection scheme can deal with the fault or an additional action is required. Three different actions are then proposed in this strategy to decrease the cases where coordination is lost. The first is based on searching for the best DG location, while the second is based on changing the recloser characteristics and the last one is based on preparing information about which DG when disconnected, the protection coordination can be re-attained. The proposed strategy is evaluated by being implemented to the IEEE 34-node test feeder. The obtained results show the ability of the classification process to discriminate between the cases where coordination holds and those where coordination is lost. Moreover, a considerable decrease in the cases classified as coordination lost after applying the proposed solutions is achieved. All the required software is developed by the authors using MATLAB m-files as a platform.