Research On Partition Strategy And Power Flow Optimization Method For Distribution Network Containing Distributed Generation

In recent years,in the context of energy conservation and the rapid development of smart grids,people have started to pay attention to the sustainable development of energy use and the improvement of environmental quality,which has made traditional fossil energy gradually fade out of the energy market.However,various new and renewable energy sources have begun to emerge,and a distributed generation(DG)with intermittent and uncertain characteristics has begun to enter people’s lives.Since then,distributed Photovoltaic generation(PV)has developed rapidly,and the technologies of PV cells and low-speed wind turbines have also progressed rapidly.The development of other renewable energy sources has also made breakthroughs in varying degrees,which has attracted the attention of the world.Among them,DG can participate in the voltage regulation of the distribution network by controlling their power to support the stability and reliability of the power grid.With the massive increase in distributed power in the future,the power distribution system will face a variety of DGs with relatively scattered locations,which will greatly increase the probability of problems such as overvoltage,reverse flow,and overloads.Nowadays,although the related technologies of DGs are becoming more mature,the phenomenon of abandoning Wind Turbine generator systems(WT)and PV is still common.To avoid this kind of situation,exploring the voltage regulation function of DG or improving the absorption of DG by the distribution network has become a topic worth studying.In recent years,researchers at home and abroad have begun to propose methods for optimizing the power flow of the distribution network in the form of partitions and combining the inverters connected to the DGs to improve the voltage in distribution network.This paper has carried out the research on the distribution network partition strategy and the Optimal Power Flow(OPF)method with DGs connected.The specific paper has carried out the following work:First of all,a series of problems of the distribution network with DGs are introduced.Then a further analysis through the Open DSS software is conducted.Subsequently,an overview of the distribution network partition based on voltage control is introduced,as well as the partition principle considering the combined control of Reactive Power Compensation(RPC)and Active Power Curtailment(APC).In order to meet the above partition principle,this paper proposes an improved partition algorithm based on voltage sensitivity and a OPF method.Under the framework of the partition strategy of RPC and APC,the addition of reactive power support capability matrix,sensitivity matrix and position matrix is further considered based on the original modularity increment index,so that the improved Fast-Newman algorithm becomes more suitable for the partition requirements of the distribution network.Secondly,the model construction of the distribution network OPF method based on the improved partition algorithm is completed,and realized the partition OPF simulation for the RPC and the APC regulation of the DGs for the regulation node set.That shows the combined control of active and reactive power output by the DGs.On the basis of the optimization model,the simulation of the OPF method described in this article is realized.It is verified that the improved Fast-Newman algorithm is practical.Finally,in order to make the OPF method consider more factors and make the optimization more reasonable,this paper introduces two sub-objectives contain minimized APC of DGs and minimized network loss on the basis of combined control of active and reactive power for combined normalization.The OPF method can be developed in a more ideal direction,making it more economical and practical.Then,a case study was operated on the modified IEEE34 node and the modified IEEE123 node.Through compared with the model simulation results of the original method,it was further proved that the method can balance multiple sub-objectives in OPF,less network loss,and more effective use of DGs.