Research On The Fault Restoration Of Distribution Network With Photovoltaic Power

With the continuous development of economy and the improvement of people's living standard,the electric power users put forward higher and higher requirements to the power supply reliability of distribution network.As a large number of distributed power supply access to low voltage distribution network,the traditional distribution network structure and operation control method change dramatically.When the power distribution system failure caused a large area blackout occurs,how to ensure that the important load power and fast recovery of power supply in the area of non-fault power failure has become an urgent problem.Based on the analysis with photovoltaic power distribution network topology and power flow calculation,the thesis takes into account the different moments of photovoltaic power and load uncertainty and proposes a fault conditions of photovoltaic power distribution network dynamic power supply recovery strategy.According to the daily output curve of photovoltaic power supply and the daily load curve during the period of recovery,the thesis establishes sample similarity evaluation index,the k-means algorithm is applied to segment the fault recovery interval and transform the dynamic fault restoration of the distribution network with the photovoltaic power into the multiple static fault recovery problems,in which the load of distribution network is represented the corresponding cluster center,the practicability of this method in engineering practice is improved.According to the operation characteristics and islanding operation ability of the distributed power supply,the isolated island partition stage should obtain the separate island power supply feasible region and the union island power supply feasible region.On this basis,the node importance and the line betweenness are taken as the evaluation index of island partitioning,island partition model is built,quantum-inspired evolutionary algorithm is used to solve the model,the feasibility of quantum chromosome is modified by depth first search algorithm.The result of example analysis shows that the method can distinguish the importance of the same level by the line betweenness and effectively improve the proportion of important load.According to the principle of distribution network fault restoration,the distribution network fault restoration stage should take the loss of electricity load,the recovery system network loss,the number of switch operation and the maximum voltage drop as the evaluation index of fault restoration,the corresponding membership function is constructed,the weights of each evaluation index are determined by the analytic hierarchy process,thus,the distribution network fault restoration model is built.The ant colony algorithm is used to solve the model,the thesis ensures the constraint of radial operation by setting up the operating switch,the effectiveness of this method in engineering practice is improved.research on fault restoration of distribution network with photovoltaic power has been completed.