Research On Distribution Network Partitioning And Reactive Power Optimization Control With Distributed Photovoltaic Integration

In recent years,with the rapid consumption of traditional fossil energy,photovoltaic power generation in distributed power sources has received extensive attention due to its resource adequacy and cleanliness.However,the intermittent and random nature of distributed PV output makes the power flow state of the distribution network fluctuate frequently.In addition,distributed photovoltaic access makes the distribution network distribution characteristics more obvious,and traditional centralized optimization control has been difficult to meet this new form of control requirements.To this end,this paper studies the distribution method of distribution network with distributed photovoltaics and the coordination and optimization of each region after partitioning.This paper proposes a partitioning method based on improved Louvain algorithm and a distributed reactive power optimization method based on partitioning coordination.The main research work of the thesis is as follows:1.Distribution network partitioning method based on community detection algorithm under photovoltaic access.Firstly,the method considers the influence of distributed photovoltaic access on the partition,and defines the electrical distance expectation matrix between nodes.Secondly,in order to characterize the in-situ balance capability of reactive power in the partition,an electrical module function is defined.Finally,in order to further improve the quality of partitioning,an improved Louvain community detection algorithm is proposed.The partitioning result of this algorithm lays the foundation for distributed reactive power optimization of distribution network based on partition coordination.2.Distributed reactive power optimization method for distribution network based on zoning coordination under photovoltaic access.Firstly,based on the convex hull relaxation technique,this method establishes a centralized reactive power optimization model for distribution networks with distributed photovoltaics.Then,based on the partition,the reactive power optimization model is decomposed into sub-optimal models of several regions by interval decoupling.Finally,the original dual-multiplier method is used to coordinate the solution of each sub-optimization model.The optimization method has the advantages of small communication burden,flexible control,and strong global optimization capability.Only a small number of variable interactions between adjacent partitions can realize distributed optimization and voltage control of global active network loss.3.Simulation analysis.The IEEE 33 node and PG&E 69 nodes with distributed PV access are used as examples to verify the simulation.The simulation results show that the distribution network partitioning method with distributed photovoltaic access can automatically obtain stable and reasonable partitioning results.In addition,the convex hull relaxation technique and the original dual multiplier method are suitable for distributed reactive power optimization of distribution networks with distributed photovoltaics,which can achieve effective control of node voltage.