Reliability enhancement method for distribution system using a network cooperation recovery optimization technique

The distributed generation (DG) and soft open point (SOP) have been connected to the distribution network, so distribution network fault recovery has changed from the single tie line recovery to collaborated recovery of DG and SOP, resulting in the reliability of distribution network is seriously underestimated under the traditional reliability assessment mode. Therefore, in order to overcome this shortcoming, this paper presents reliability assessment methodology for enhancing reliability of electrical distribution system using a network collaboration recovery technique. The paper employs a highly flexible model to fully exploit the synergistic restoration potential of flexible resources, enabling precise reliability evaluation through the formulation of optimal fault recovery strategies. Firstly, the restoration strategy for SOP and tie line reconfiguration in coordination with DG islanding is proposed in order to consider the mutual influence between SOP and DG in fault recovery and fully explore the collaborative recovery ability of DG and SOP; Secondly, this paper proposes a radial network constraint method that allows island recovery and load shedding operations. The method ensures to obtain the optimal solution for the restoration strategy while constraining the radial operation of the distribution network; Thirdly, in order to improve the computational accuracy of the proposed model, this paper uses the big M method and second-order cone relaxation to transform the model into a mixed-integer second-order cone programming problem and solves the model using a solver; Finally, the effectiveness and superiority of the proposed method is investigated through the case study on IEEE 33 and 54-node distribution systems, and the SAIDI index can be reduced by 5.98% for IEEE 33 system and 3.07% for 54-node system.