Research On Reactive Voltage Optimization Strategy Of Photovoltaic Power Distribution Network

In today's society,the problem of fossil energy exhaustion,energy security and environmental pollution has been paid more and more attention.In today's society,the demand for renewable energy is gradually increasing.The government has introduced policies to encourage the development and utilization of wind and solar energy,so as to realize resource conservation and environmental friendliness.Due to the randomness and uncertainty of photovoltaic power generation and the mismatch between photovoltaic power output and load consumption,the voltage fluctuation of the distribution network becomes more and more obvious after the photovoltaic power is connected to the distribution network,and the distribution network is prone to voltage over-limit.Under the premise that the development of society and economy requires higher and higher power quality,this paper makes an in-depth study on the photovoltaic power supply participating in the voltage optimization of distribution network.The content of this paper is as follows:Firstly,a photovoltaic power generation and grid-connection model is established,on which the influence of grid-connection of photovoltaic power on load flow,network loss and voltage deviation of the distribution network is analyzed.Based on the equivalent circuit of the grid-connected photovoltaic power supply,the influence of grid-connected photovoltaic power supply on the over-limit voltage mechanism of the distribution network is analyzed.According to the Matpower simulation software,the single photovoltaic power supply and multiple photovoltaic power supply connected to the distribution network are studied,and the influence law of photovoltaic power supply on the distribution network voltage under different conditions is obtained.Secondly,the improved genetic algorithm is used to optimize the reactive power of the distribution network with photovoltaic power supply.On the basis of considering the minimum loss of the active power network and the minimum voltage deviation,the static and dynamic reactive power optimization models are established respectively.The static reactive power optimization model compares the initial power flow,particle swarm optimization(pso)and the improved genetic algorithm(ga)to optimize the IEEE33 node,and concludes that the improved ga can effectively reduce the active power loss and voltage deviation of the distribution network.Based on the calculation of photovoltaic output fluctuation and load change,the dynamic reactive power optimization divides the whole day into 24 hours.On the basis of considering the number of actions of the reactive power compensation equipment,the IEEE33 node is used for the example simulation analysis.Finally,in view of the errors in the prediction of photovoltaic output and load fluctuation,a dual-time-scale reactive power optimization model covering day-ahead planning and day-long short-term scheduling is designed to coordinate discrete equipment and continuous equipment.Among them,the current plan is to optimize the distribution network with the minimum active power loss as the goal,with the output of reactive power compensation equipment and the transformer ratio of on-load voltage regulation as variables,and with the discrete device action times of adjacent time scale as the constraint.With the minimum voltage deviation of distribution network node as the target,the output value of photovoltaic power supply and SVC as the variable,and the voltage of each time scale obtained by day-ahead plan optimization and the action time and action amount of discrete equipment as the reference value,the distribution network is optimized.Through the coordination and optimization of multi-equipment and double-time-scale,the distribution network can operate safely and economically.