Optimization Of Loop-Network Reconfiguration Strategies In Power System Restoration With Large-Scale Wind Power Integration

With the proposal of dual carbon goal including carbon peak and carbon neutral,it is urgent to build a clean,low-carbon,safe and efficient energy system.In the future,the proportion of new energy such as wind power will be further increased.The large-scale wind power integration brings opportunities and challenges for emergency restoration of power system.As the key stage in the power system restoration process,network reconfiguration plays a significant role in the rapid and safe system restoration.The wind power uncertainty puts forward more stringent requirements for the carrying capacity of the recovered network.Under this background,this paper focuses on the optimization of network reconfiguration when large-scale wind power integration and studies from three aspects: the scenario modeling of wind power output,the determination of the target network with wind power,and the strategy to eliminate line overloads.The main contents of this paper include:(1)The ability of radical network to carry wind power is analyzed,and the multi-scenario set of wind power output is constructed.According to the structural characteristics of the radial network,the network capacity for wind power uncertainty is analyzed.The result shows that the carrying capacity of radial network is poor,which threatens the network safety.Therefore,a restoration scheme is proposed by putting some lines into operation to construct loop-network.Considering the wind power uncertainty,a multi-scenario set of wind power output is constructed based on the extreme scenario method.Then it is used to better serve the determination of the subsequent target network and the method to eliminate line overloads.(2)Based on the proposed restoration scheme,the loop-network satisfying the multi-scenario set of wind power output is constructed.Firstly,based on the electric network theory,the analytical expression of loop-closing operands about branch switching is obtained.Then,the optimization model of target network considering wind power output is established.In order to solve the problem of complex model,the original model is decomposed into two layers,and an iterative solving strategy based on the infeasible cut linear constraint is adopted.The rationality of the proposed scheme is verified by IEEE-30 bus system with wind power integration.(3)Aiming at the problem of line overloads during the network reconfiguration,an optimization method for loop-network restoration considering multi-scenario sets of wind power is proposed.Firstly,a model is established with the goal of minimizing the comprehensive operation number.Then,the model is layered and iteratively solved.An optimization model considering DC power flow constraint is established to obtain the proposed lines.The AC power flow constraint and the standing phase angle(SPA)constraint are checked for the lines.Finally,the optimal loop-network restoration scheme to eliminate line overloads is formulated.The effectiveness of the proposed strategy is verified by IEEE-39 and IEEE-118 bus systems with wind power integration.