Research On Optimal Operation Control Of Reactive Power Coordination In Active Distribution Network

With proposition and development of the active distribution network,a large number of distributed generation access to the network,that greatly affect the voltage,the distribution of the power flow and the loss of the network.However,a s an important index of power quality and power supply economy,the distribution network voltage and active power loss are greatly influenced by the distribution of reactive power flow.Therefore,based on reliable real-time data,through reactive power coordinated optimization of distribution network,it is necessary to control equipment switching and changing reactive power output of DG,so that network power flow can achieve optimal distribution.It is an important measure to ensure the safe and economic operation of distribution network.In this paper,the optimal operation control strategy of reactive power coordination in active distribution network and related problems are studied,mainly in the following aspects.The main characteristic of the active distribution network,which is different from the traditional power grid,is DG with high permeability.Therefore,the qualitative and quantitative analysis of the impact of DG access on the distribution network can reasonably analyze its role in the reactive power optimization control.this paper modeled the common DG and its active and reactive power Then,the influence of DG on the grid voltage and active power loss is simulated and analyzed by theoretical and numerical examples.Based on that,the influence of D G on reactive power regulation is further analyzed,which provides a strong basis for further research.Real-time and accurate running data is the premise and foundation of ensuring the optimal results of reactive power coordination and Optimization in ac tive distribution network.However,the number of users in distribution network is large,and the metering devices such as advanced metering infrastructure(AMI)and synchronous vector measurement unit(PMU)have not been widely applied because of the huge cost and easy to increase the burden of communication,resulting in insufficient real-time measurement in some parts of the distribution network.The equipment operation scheme obtained by using SCADA data directly to optimize the operation of reactive power is poor.So this paper is aimed at the shortage of real time measurement in distribution network,proposed a state estimation method for active distribution network based on Forney factor graph.The method uses the belief propagation algorithm which running on the distribution network factor diagram to do the real time state estimation so as to improve the accuracy and integrity of the data.At the same time,on the basis of the method,this paper optimizes the placement position of the measurement,so that the precision of state estimation is further improved.Finally,aiming at some problems of voltage and reactive power optimization in active distribution network,based on traditional reactive power optimization method,this paper proposed a reactive power hierarchical optimization control strategy for different voltage levels in active distribution network,which divides the reactive power control area into two optimal layers under the voltage level,through coordinating the two layers of coordination variables,we coordinate and control reactive power compensation devices between different optimization levels to switch and regulate reactive power output of DG,so as to achieve the purpose of reactive power optimization operation of the whole network.In this paper,the Matlab is used to model the example,and the simulation and operation simulation of the fixed time period of the active distribution network is carried out.The simulation results verify the effectiveness and feasibility of the proposed method.On this basis,the relevant conclusions are drawn and the follow-up research is prospected.