Research On Method Of Location Selection And Capacity Determination Of Connecting Distributed Generation To Distribution Network

In recent years,power has become the core of new round of energy revolution.Distributed generation(Distributed Generation,DG)is getting more and more attention and application because of its unique technical advantages.When the DG has an access to the distribution network,it has a certain impact on the power flow,network loss,node voltage and reliability of traditional distribution network.How to choose the reasonable location and capacity of DG to make the distribution network run more reliably and economically is a problem which needs to be solved urgently.Based on this,this thesis mainly researches on the reasonable choice of DG's location and capacity in distribution network.Firstly,the influence of grid-connected DG on distribution network planning,network loss and voltage is analyzed,and the importance of rational selection of DG grid connection and capacity to safe and stable operation of distribution network is clarified.Then,the power flow calculation of distribution network with DG is studied.Different types of DGs are abstracted into mathematical models which can be used in the calculation of power flow,and its corresponding node types are summarized.The processing method of the node type is analyzed for the calculation of power flow,and the IEEE-33 node system is used as the simulation system,and it is to verify the correctness of the power flow calculation of distribution network with DG using back/forward sweep method.On the location problem of DG,DG is divided into the type of power random DG and power controllable DG,and the output power models of fan,photovoltaic and fuel cell are established.The assessment of the node is based on the the improvement index of network loss and voltage stability index which are the main basis,and the actual situation of the distribution network and other related factors are considered.DG's optional installation location is choosed based on those factors.The optimization model of choosing location and capacity of DG is established based on the minimum sum of the cost of the power purchased by distribution network every year and the comprehensive cost of DG's investment every year.The basic particle swarm algorithm is studied and its learning factors and weights are improved.The correctness of the improved particle swarm algorithm is verified by the classical function.Finally,taking the distribution system of IEEE-33 node as an example,the improved particle swarm optimization algorithm is used to solve the access planning schemes of DG including wind power,photovoltaic and fuel cell.The distribution network with DG is compared with the distribution network without DG from the aspects of economy,voltage stability and network loss.It can be found that reasonable access of DG can bring better economic benefits and operational reliability to distribution network.