Research On Distributed Photovoltaic Grid-connected Voltage Control Strategy Based On Power Prediction

It is extremely urgent to develop clean energy and reduce the use of traditional fossil energy since that would be the only choice for human beings to achieve sustainable development.At present,clean energy power stations around the world have been put into good use.Compared with traditional large-scale centralized power generation,distributed generation is relatively independent,not only has a short construction period,flexible installation location,but also can provide power quality to regional power grids.And real-time control of performance,the advantages are obvious.Research on distributed photovoltaic power generation and related grid-connected technologies has become the current theoretical and engineering circles hot issue.As the distributed PV penetration rate continues to increase,the output power fluctuates greatly,the harmonic content of the power grid increases,and the voltage exceeds the limit.The research work in this paper is mainly aimed at the deployment of the distribution network voltage.Firstly,by analyzing the front and back of the distributed photovoltaic access distribution network,as well as the single photovoltaic power supply access and multiple photovoltaic voltage access situations,it is found that the location of the access point,the input power,etc.The limit of the voltage is decisive.Secondly,aiming at the shortcomings of existing power prediction methods,a BP network photovoltaic power prediction method based on day type and fusion theory is proposed.The weather type and the factors affecting the PV power output are fully considered,and the information fusion theory is used to reduce the prediction.At the same time,the input quantity of the model ensures that the influence factors are not missing.By optimizing the model parameters to improve the prediction speed,the error correction improves the prediction accuracy again and obtains a better prediction effect,so that the predicted value of the feeder voltage at the next moment is relatively accurate.Finally,considering the single useful reduction of economic deficiency and limited reactive power regulation capability,a coordinated power distribution voltage control strategy based on power prediction is proposed,which fully utilizes the residual reactive power regulation capability of each inverter to reduce the investment in energy storage equipment.Or,in-situ consumption through flexible load,to achieve the maximum power output of distributed photovoltaics.The paper analyzes the power flow after the distributed photovoltaic access distribution network,and obtains the mechanism of the overvoltage occurrence of the feeder after the distributed photovoltaic grid connection.It is found that the photovoltaic power output fluctuation has great influence on it.In order to reduce the possibility of voltage over-limit,this paper proposes a power distribution-based voltage regulation strategy based on power prediction.It tries to predict the relationship between the output voltage and the feeder voltage through a more accurate photovoltaic power prediction.Size,make adjustment strategy choices in advance.Finally,the simulation software is used to analyze the results.It is proved that the prediction mode and the voltage regulation strategy are feasible,which is conducive to the energy consumption and regulation of large-scale distributed photovoltaic systems accessing the distribution network.