Optimization of loop-network reconfiguration strategies to eliminate transmission line overloads in power system restoration process with wind power integration

With large-scale wind power integration, the uncertainty of the wind power outputs will aggravate the transmission line overloads during the black-start restoration process. By constructing regional loop-networks, this paper proposes an optimization method of network reconfiguration strategies to eliminate the line overloads. Firstly, a multi-scenario set of the wind power outputs is constructed based on the extreme scenario method. Secondly, a loop-network reconfiguration optimization model is established to meet the requirements of the multi-scenario set simultaneously, where the line overloads are not permitted. Then, a two-layer solving framework is proposed to solve the optimization model. The upper-level layer is a multi-scenario mixed integer linear programming (MILP) model with the DC power flow constraints, whose objective is to minimize the operation complexity index. The lower-level layer serves to check the standing phase angle (SPA) constraint and the AC power flow constraints of the optimal schemes obtained from the upper-level layer. Therefore, the loopnetwork reconfiguration optimization model is alternatively solved by iterative computation. The effectiveness of the proposed method is verified by the modified IEEE 39-bus system and the modified IEEE 118-bus system, and applicability of this method to practical systems is verified by the southwestern Yunnan power system in China.