Research On Prediction Model Of Grid-connected PV System In High-altitude Desert Area

With the advent of the global energy crisis,the sustainable green energy is used more and more widely,and the utilization rate of photovoltaic industry is getting higher and higher in high-altitude desert area.When large-scale photovoltaic power generation system is connected to the power grid,the challenge to the Power Grid Corp is becoming increasingly serious.There are two main challenges: first,the output power of photovoltaic system is intermittent and volatility,when large-scale photovoltaic power generation system is connected to the power grid,it will bring challenges to Power Grid Corp's scheduling management and power balance and power generation security and stability.Second,the green energy enjoys high electricity prices when it compared with other energy.Power Grid Corp must prevent to measurement errors and illegal behavior of electricity generation for the gap between import and export electricity prices.In order to make full use of green energy,and ensure the safe and reliable operation of Power Grid Corp,it is necessary to predict the output power of grid-connected photovoltaic power system accurately.Therefore,in view of the special climatic conditions in the high-altitude desert area,the prediction model of output power for grid-connected photovoltaic power generation system is established.In this paper,mainly studies and discusses about the following aspects:1.Compared with other regions in China,there have the characteristics of low ambient temperature in the high-altitude desert area.Under the climatic conditions,the prediction model of output current is calculated based on the analysis of equivalent circuit of silicon PV panel.The modified formula is presented for improving the accuracy of open-circuit voltage,short-circuit current,maximum current and maximum voltage.Furthermore,the improved output current prediction model is established for the high-altitude desert area.2.Based on the topology of the PV power stations,electric power exchange relationship of each link is analyzed.The under prediction model of output power is proposed,made use of the improved output current prediction model in the high-altitude desert area and relationship between power and voltage-current.3.The comprehensive error curve is obtained,comparing the daily under predicted power curve with actual output power.Comprehensive error expression is obtained using the probability estimation method.The output power prediction model for photovoltaic system is established which adapt to the high-altitude environment,while comprehensive error compensation to the under predictive power model.