Research On Optimization Of Reactive Power Compensation Of Power Grid Considering Reactive Power Of Inverter

With the extensive development and utilization of fossil energy in various countries,mankind is facing a huge problem,that is,the energy crisis.Solar energy is likely to become one of the most promising alternative energy sources.With the photovoltaic grid-connected technology becoming mature,more and more photovoltaic power generation systems are connected to the grid,which not only feeds power to the grid,but also has a certain reactive power regulation ability,so photovoltaic inverter is also one of the important reactive power sources.Studying the control strategy of photovoltaic inverter and bringing the reactive power regulation capability of photovoltaic inverter into the optimization of reactive power compensation can not only improve the power flow distribution of power system,but also improve the stability and economy of power system operation.Based on this,the main work of this paper is as follows:Firstly,the effects of off-grid and grid-connected photovoltaic power generation systems and grid-connected photovoltaic power generation systems on power loss and voltage stability are introduced.then,the reactive power capacity of the inverter is analyzed from three aspects: the principle of reactive power compensation,reactive power and voltage support capacity and reactive power output limit,which lays a theoretical foundation for the subsequent inverter power control.Secondly,the mathematical model of the circuit topology of the grid-connected three-phase inverter is established,and the voltage vector control strategy of the inverter is analyzed.Based on the idea of model predictive control,it is applied to the power control of grid-connected three-phase inverter.on this basis,this paper proposes to take the minimum sum of the square error of the predicted and reference values of active and reactive power in each sampling period as the performance index function,and through the on-line prediction objective function,select the voltage vector that makes the inverter run in the optimal state and trigger the pulse directly.The output power can quickly track the reference power.Compared with the voltage vector control,the structure of the method is simple,no other additional modulation techniques are needed,and the parameters are easy to be designed.The superiority of the proposed method is verified by simulation experiments.Finally,it is proposed to bring the reactive power regulation capability of photovoltaic inverter into the reactive power compensation,taking into account the multi-objective requirements of system operation stability,power quality,economy and compensation cost.the power grid multi-objective reactive power optimization method with reactive power regulation capability of photovoltaic inverter is studied.A multi-objective reactive power optimization mathematical model considering inverter reactive power is established with minimum power loss,minimum reactive power compensation and best voltage stability.Around the multi-objective problem of power grid reactive power compensation optimization,an improved niche multi-objective particle swarm optimization algorithm is proposed to solve the multi-objective optimization model in this paper,which provides more flexible solutions for decision makers.Finally,the inverter model predictive power control and the traditional control method are applied to the power grid reactive power compensation optimization scheme considering the reactive power of photovoltaic inverter,and the superiority of the model predictive power control strategy proposed in this paper is verified.