Research On Distribution Network Optimization Considering Comprehensive Vulnerability Of Distribution Network

The distribution network is becoming larger and more complicated,and its operation safety is gradually receiving more and more attention.The irrational operation structure of the power grid will greatly reduce its own robustness,which is easily caused by fluctuations in the flow.The failure directly reflects the weak vulnerability of the power grid structure,and it is necessary to optimize the operating structure of the power grid,which requires the use of power grid reconstruction and optimization techniques.On the other hand,as the distribution generation(Distribution Generation,DG for short)connected to the power grid gradually increases,the changes in the power flow also become complicated,and the location and access of irrational DG access nodes in the power grid The capacity will also reduce the vulnerability of the distribution network.Therefore,it is necessary to use the grid optimization configuration technology to reasonably optimize the location and capacity of the DG connected to the grid.Firstly,aiming at the fragility research of the power grid,taking the fragility of the power grid as the starting point,based on the complex network theory,the index of the fragility of the power grid is comprehensively formed based on the degree of the branch and the number of the branches.Further in-depth study of the impact of various operating electrical parameters of the power grid on the fragility of power grid branches,and then proposed indicators for evaluating the fragility of the motion status of the power grid branch,thereby forming a comprehensive evaluation of the power grid branch from the grid structure level and the grid operating state level.Vulnerability indicators.Then based on the comprehensive vulnerability index of the power grid branch,from the perspective of considering that the mean value of each branch of the power grid and the balanced distribution of the value can affect the overall vulnerability of the power grid,the comprehensive vulnerability index of this branch For the transition,a comprehensive grid vulnerability index that can describe the overall vulnerability of the grid is proposed.Then establish a multi-objective grid reconstruction optimization model that takes into account the comprehensive vulnerability index of the power grid,construct a comprehensive optimization objective function that uses the comprehensive grid vulnerability index and the grid line active loss index to reconstruct and optimize,and then propose an adaptation to the optimization objective function This paper uses an improved quantum particle swarm algorithm.Compared with the original quantum particle swarm algorithm,this algorithm adds a shrinkage expansion coefficient to the particle evolution equation,and then achieves the purpose of adjusting the shrinkage speed of the particles.The scope of the initial optimization can be as large as possible to avoid falling into local optimization.On the other hand,the optimization scope can be as small as possible at the end of the iteration to achieve the goal of the algorithm’s rapid convergence.At the same time,a more suitable integer ring network coding is used in the particle coding,which greatly improves the effective solution ratio in the formed solution space.Finally,the above examples are used to analyze the static reconfiguration of the power grid,and the validity of the model is verified.Based on this,the dynamic reconfiguration optimization of the power grid is further carried out,and the corresponding dynamic reconfiguration period division strategy is proposed,and the corresponding example analysis is performed to verify the effectiveness of the strategy and model.Furthermore,an optimal configuration model for DG access to the power grid is established,and a dual-objective optimization function that takes into account the vulnerability index is also constructed.The above-mentioned improved quantum particle swarm algorithm is combined with a particle coding method that optimizes the fusion of position and capacity to form Optimal power grid configuration model.Based on this model,a case study of a single-DG access optimization configuration for the entire network and a case study of a fixed optimization area more in line with the actual situation were performed to verify the effectiveness of the model.An example of grid optimization configuration based on the grid operation structure.The results show that the combination of grid reconfiguration optimization and grid optimization configuration can maximize the overall optimization of the grid operation.