Research On The Method Of Improving The The Acceptance Ability Of The Distribution Network To DG

At present,the excessive exploitation of fossil energy and the serious environmental pollution caused by its combustion accelerate the pace of human beings to find new energy.Therefore,Distributed Generation(DG)has attracted unprecedented attention from all countries due to its advantages of clean and pollution-free.As a result,people began to consider the development level of DG,but when it is connected to the distribution network,it will cause many adverse changes,such as voltage distortion,so the reconfiguration of distribution network is used to study this problem.The reconfiguration of distribution network is to change the switch state of some branches in the distribution network and optimize some parameters of the distribution network,so as to improve the system performance.This optimization tool helps to change the network configuration,and use the optimal power flow in the network to improve its function.Based on the in-depth study of the domestic and foreign related results,this paper studies the reconfiguration method of distribution network to improve the acceptance ability of the distribution network to DG,mainly as follows:Firstly,the necessity and benefits to develop DG are expounded.The regulations on the maximum acceptance capacity of distribution network to DG and the methods of improving the acceptance ability of the distribution network to DG at home and abroad are studied,including the innovation method for distribution network components and the reconfiguration method of distribution network for distribution network structure(its effect determined by the advantages and disadvantages of the algorithm),etc.Secondly,the influence of DG access on the distribution network is analyzed,including loss,power quality,planning,protection,reliability,etc.In the above aspects,the change of network loss is especially expounded.The calculation results are deeply analyzed,and the conclusion that the location and capacity of DG are closely related to the network loss is reached.Then various types of distribution network power flow strategies are enumerated.The advantages and disadvantages ofeach strategy are compared to find that the back/forward sweep method,which has many advantages,such as not requiring admittance matrix,employing small memory,easily converging,simply programming and unnecessarily sparsely processing,is selected.At the same time,in order to make the strategy more efficient and more easily integrate into the distribution network model with DG,the improvement measures of the strategy are added.At last,the goal and related limitation of the distribution network model with DG are determined.Thirdly,the grid connection interface and power flow model of various types of DG are given.In addition,the concept of Plant Growth Simulation Algorithm is described.Regarding the lowest network loss as the objective function,Plant Growth Simulation Algorithm is used in the reconfiguration of distribution network.The MATPOWER flow calculation software based on MATLAB language is used to ensure high calculation accuracy.The example shows that the model can reduce the network loss and raise the network voltage level at the same time.Finally,Plant Growth Simulation Algorithm is improved.The improved Plant Growth Simulation Algorithm uses the strong global search ability of Particle Swarm Optimization with high inertia weight to find the initial growth point next to the global optimal solution,so that Plant Growth Simulation Algorithm can quickly converge to the global optimal solution.At the same time,the improved formula is used to reduce the size of growing point set so as to optimize its operation efficiency.Then the improved PGSA-PSO is used in the reconfiguration of distribution network with the stationary capacity and floating address DG as well as stationary address and floating capacity DG.And the improved back/for-ward sweep power flow method for the distribution network is adopted.The test results of 33 nodes confirm the feasibility and efficiency of the configuration.Compared with the related literature,this method can obtain the optimal configuration results faster,greatly reduce the loss,and in the condition of the stationary capacity and floating address DG as well as stationary address and floating capacity DG,the network structure after the reconstruction of distribution network will be affected by the address and capacity respectively.Based on the improved PGSA-PSO,the reconstruction ofdistribution network can not only reduce the network loss by a more wide margin,but also improve the acceptance capacity of distribution network to DG,and make DG connect to the appropriate position,that is,on the premise of ensuring the system economy,it can improve the acceptance capacity of DG as much as possible.