Experimental studies of factors of influence on solar generation power plants

Abstract

Intensive development of grid-connected solar power plants leads to significant problems of management and reliability of the country's electrical systems, due to the stochastic nature of weather phenomena, such as clouds, rainfall, fog and others. Therefore, forecasting the generation of solar power plants is an important issue as improving the reliability of the country's electrical system and improving the economic efficiency of solar power plants by reducing fines for imbalances in electricity. Experimental studies have been conducted to determine the influence of natural factors, such as the angle of the sun over the horizon, temperature of photovoltaic modules, solar radiation, contamination of module surfaces, precipitation and fog on the generation of 2.4 MW solar power plant located in Kharkiv region of Ukraine. The study found a clear relationship between the active power of the solar station, solar radiation, ultraviolet index and the surface temperature of the photovoltaic module. The nature of changes in solar radiation during 12 months of observations was established, the minimum solar radiation of 200 W/m2 was recorded in December, the maximum solar radiation of about 1200 W/m2 was observed in June. Based on statistical data, the dependences for determining the difference between the surface temperature of solar panels and the air temperature on a clear day depending on the hourly generation of the solar power plant are obtained. It is established that the generation of a solar power plant at 100 % cloud cover is from 20 to 28 % compared to the generation on clear days. Contamination of the surface of photovoltaic modules and their cleaning depending on the intensity and amount of precipitation has a significant impact on the generation of a solar power plant. Fog has a significant effect on lasing, which reduces lasing by 50 %. Graphs of specific generation (ratio of hourly generation of solar power plant, in terms of solar panel temperature 25 °C, to the average hourly angle of the sun above the horizon), which will help determine the generation of solar power plant for each hour during the day. To increase the accuracy of generation forecasting, the specific generation graphs are divided into two intervals: the first and second half of the day. Analysis of specific power graphs suggests that the specific generation varies throughout the year due to different air temperatures, air vapor content and the thickness of the layer of air through which the sun's rays pass, depending on the location of the sun above the horizon.