Research On Reactive Power Optimization Method Of Distribution Network Based On Voltage Control Target Tracking

The state’s investment in distributed energy is increasing.But distributed energy also has its inherent disadvantage to solve the energy gap,that is,the distributed energy can not provide long-term and stable effective force.The existence of these characteristics has brought great influence on the operation of power grid,and the influence of distributed PV grid connected to the power grid is mainly to change the reactive power distribution in the distribution network.Therefore,the control strategy of voltage and reactive power after distributed photovoltaic access system is studied in this paper.The main research work done in this paper is as follows:Firstly,the influence of distributed photovoltaic intervention on power grid is analyzed.The structure of distributed photovoltaic(distributed photovoltaic)is introduced.The influence of distributed PV access system on reactive power distribution and voltage distribution of power grid is studied.The results show that the distribution network is mainly radiated or chain network.After distributed PV access system,the power and reactive power of the whole transmission line will be reduced.Therefore,the higher the access point is,the more obvious the voltage is corresponding to the terminal.Secondly,the technical comparison and selection of voltage control methods based on reactive power compensation are carried out.At present,the voltage control in our country is controlled by the method of stratified partition,and the capacitor or reactor is usually installed at the 10 kV bus bar of the substation.This method of reactive power regulation can not be applied to the voltage rise or fall at the end of a branch.Therefore,this voltage control mode can not be effective for voltage rise after distributed photovoltaic access.And SVG has the function of emitting and absorbing reactive power,so the installation of SVG in the key node can compensate and absorb the active and reactive power transmitted on the line,and play an effective control of the voltage.Finally,the external point penalty function optimization method is introduced to control the voltage distribution of the distribution network connected to the distributed photovoltaic system.Taking voltage control as the objective function,the capacity of SVG is taken as a penalty term to solve it.In order to achieve the purpose of controlling the voltage fluctuation under the condition of smaller input SVG capacity,A case study in Jiangxia District of Wuhan is carried out.The test results show that SVG can effectively change the voltage distribution of distribution network and reduce the three-phase imbalance in distribution network.