Multi-stage Service Restoration for Distribution Network with DGs

Abstract

 In order to solve the problem of fast service restoration in distribution network with distributed generators （DGs），a multi-stage service restoration method is proposed. The service restoration method organically combines the four phases of service topological identification，islanding，connectivity restoration with main network of DGs and network reconfiguration，and load shedding operation. Once the distribution network is faulty，the service area is identified by the service topology identification method to determine the next stage of service restoration execution and to update the topology parameters. During the island configuration phase，the islanding method based on depth-first search algorithm is proposed，Which gives the priority to restore the key load and maximum loads as the goal and to improve the utilization of DGs. Heuristic rules to optimize the tie switch quickly restore the out-of-service areas and main network connectivity. Network reconfiguration phase based on the parent-child list rules avoids infeasible solution The flow calculation is used to verify whether or not the next phase is executed. The load shedding stage removes the non-critical load to ensure the stable work of the system. The example shows that this method is suitable for the case of large-scale out-of-service，multiple failures，and cascading failures in the distribution network with DGs. It can make an effective restoration strategy according to the actual situation and improve the efficiency of complex fault restoration with strong applicability.

Keywords: distribution network,  service restoration,  distributed generators,  intentional islanding,  network optimization