Research On Distributed Generation Optimal Allocation About Static Voltage Stability Of Distribution Network

With the gradual depletion of traditional fossil fuels,increasingly severe global environmental problems,frequent occurrence of transmission accidents in centralized large power grid,Distributed Generation(DG)with its flexible,economic and environmental advantages,DG has become a hot area of research in the global power industry and has received wide attention and application.Distributed Generation has good environmental benefits,it has the advantage of flexibility and reliability to solve the power consumption of special users when the power supply demand or load changes.At the same time,the stability of traditional large power grid plays an auxiliary and supporting role.However,due to the Distributed Generation technology,most of them are connected directly to the regional power grid,Because the difference of their capacity,grid-connected nodes and Grid connected mode,and the differences in performance,A series of power quality problems can be brought by the large scale Distributed Generation connected to the power grid.Such as voltage fluctuation,harmonic,frequency disturbance,etc.Voltage level,as an important indicator to measure the quality of electric energy.Considering Static voltage stability of distribution network,To ensure the voltage level of distribution network after grid connected distributed generation,Is an important aspect of the research of Distributed Generation technology.Based on this,this paper carries out the following research work.Firstly,this paper introduces the types and characteristics of the Distributed Generation,and establishes the mathematical model.And then analyzes the influence on the static voltage stability of Distribution Network after the distributed Generation connected in Distribution Network.The IEEE 33-nodes test system and MATLAB simulation software is used to compare 4 impact factors,including the number of DGs,their locations,capacities and the power factors.On the voltage stability assessment index L,it presents two cases,one is an single DG connected to single feeder bus and another is multiple DGs connected to multiple feeder buses.Simulations studies have been carried out on test system,comparing the voltage stability assessment index L,which shows that multiple DG connected to multiple feeder buses is more beneficial to voltage stability of distribution networks.In order to improve the static voltage stability of Distribution Network,a Distributed Generation optimization scheme is proposed.In the case that the number,capacity and location of the Distributed Generation connection are uncertain,the optimization mathematical model of distribution network with distributed generation is established.With DG connection capacity maxminum,Distribution Network static voltage stability index L minimum and the maximum node voltage deviation Vpcmax becomes smallest as optimization goal,The node voltage deviation Vpc is less than seven percent as constraint conditions,Using adaptive particle swarm optimization to optimize the configuration of DG.Thus,the static voltage stability of the whole Distribution Network is improved,and a set of optimal access scheme for distributed generation is obtained.In order to verify the feasibility of the proposed scheme,through an actual Distribution Network in a certain area of Chongqing,a practical example is verified.The correctness and feasibility of the scheme are proved.