| In recent years,with the gradual failure of traditional energy and the continuous deterioration of global environmental and climate problems,in order to make the better development of power science and technology,the distributed generation technology based on wind power generation,photovoltaic power generation and other new energy has gradually become the trend of power grid operation and development.However,a large number of distributed power sources connected to the distribution network will have great changes to the traditional distribution network structure and operation mode.Therefore,it is very important to restore the distribution network faults with distributed power supply quickly and effectively under the premise of ensuring the stable operation of the power grid.In this paper,we propose a multi-stage fault recovery method based on the improved quantum particle swarm algorithm,with the island division and network reconstruction of the distribution network.The main work is as follows:1.Based on the structure of the distribution network,the topology of the distribution network is analyzed based on the concept of graph theory,and the forward generation method of node stratification is selected to calculate the power flow of the distribution network.The simulation of power flow calculation analyzes the influence of the access location of DG on the distribution network.We conclude that the voltage increase of the whole network is not obvious when the distribution is near the power point.2.Taking the priority to restore the important load and realize the load recovery as the main target function,and establish the island division model.Select the depth-first search algorithm to search and check for running island search.Complete the initial power supply restoration.Finally,PG&E 69 node distribution system and the isolated island partition system can be obtained.3.Establishing a distribution network reconstruction model with network loss value and node voltage deviation as the target function,and use the network reconstruction of the distribution network to make it better applied to fault recovery.However,the standard quantum particle swarm algorithm is prone to precocious phenomenon,which reduces the global search ability and affects the effect of fault recovery.Therefore,we use the decimal encoding and introduce the differential evolution operator to improve its algorithm,so that the objective function can reach the optimal value.Through comparative simulation analysis,the network loss value of the distribution network system after using the improved algorithm is reduced by 10.4%compared with the original algorithm,and the voltage difference of the node is also reduced by 16.8%,which ensures the stability of the power grid operation and proves the superiority of the algorithm in this paper.4.A multi-stage fault restoration method is adopted for the multi-fault distribution network.After the fault occurs,the fault type is analyzed through topology identification,then the non-fault power loss area is isolated,and the main network connectivity is restored for network reconstruction.Finally,the load cutting operation is determined through the current calculation to ensure the voltage stability.This method can better meet the applicability of fault recovery and improve the efficiency of fault recovery.Through simulation analysis,the proposed multi-stage fault restoration method can effectively solve the distribution network fault problem.For multiple fault restoration,by comparing the simulation analysis with the genetic algorithm and the taboo search algorithm.It can be seen that the time consumption of the algorithm effectively reduces the network loss and ensures the stability of the node when the voltage is reduced by 10%and 21.13%compared with the other two algorithms,effectively improving the efficiency of fault restoration. |
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