Optimization Strategy Of Skeleton Network Reconfiguration After Blackout Coordinating Recovery Of Units And Important Loads

Network reconfiguration is a connecting stage for the recovery process after a blackout of power system.A reasonable network reconstruction scheme could make full use of the generation capacity restored to energize the blackout stations as soon as possible and lay a foundation for the comprehensive restoration of the loads.Units are divided into network layer units and plant layer units,which can describe the power system more exactly and consider the situation of units more detailed.In former skeleton network reconfiguration studies that consider the two-layer unit model,the restoration of important loads are neglected.In this thesis,a two-layer unit restarting coordinated with important load recovery optimization model is established.By studying the interaction of two-layer units and important loads,the coordinated multi-objective hierarchical restoration method for units is proposed.The continuous unit restoration process is divided into sequential time steps.For each time step,the non-dominated sorting genetic algorithm and the combined use of CRITIC objective weighting method and grey relation projection method are employed to solve the unit restoration optimization problem.Furthermore,the fuzzy analytical hierarchy process and the greedy algorithm are employed to determine the restoration scheme of important loads for each time step.The effectiveness of the proposed method is validated by the optimization results on the New England 10-unit 39-bus power system.Because of the complexity of system restoration after blackout,the continuous restoration process is divided into several fixed interval time steps.However,the time consuming of energizing paths are neglected.In this thesis,a hierarchical skeleton reconfiguration strategy based on dynamic time step modeling is proposed.Considering the unit ramping time and time consumption of recovering energizing paths during system restoration process,a dynamic time step partition mechanism is established.For each time step,utilizing stratified sequential algorithm to optimize the network-layer units,plant-layer units and important loads.More concretely,using start-up power constrain as global constrain and adding the unit and load pre-selection mechanism,the optimization of units restarting and important loads recovery is realized by backtracking algorithm and greedy algorithm respectively.The effectiveness of the proposed method is validated by the numerical results of a restoration example based on the New England 10-unit 39-bus power system.