Research on performance ratio composition and standard energy efficiency ratio correction method of photovoltaic power station

Abstract

The performance ratio (PR) of the system is used to quantify the power generation efficiency of the photovoltaic power generation system. The size of the index is affected by many factors. After the environmental impact is compensated, the standard energy efficiency ratio (PRstc) of the system is obtained. PRstc is an important index for evaluating the power generation efficiency of photovoltaic power stations. Improving the accuracy of PRstc is conducive to improving the state evaluation and analysis capabilities of power stations, providing a theoretical basis for comparative analysis of photovoltaic power stations in different regions, and improving the scientific operation and maintenance of power stations. The PRstc calculation method of the industry standard NB / T 10394-2020 does not consider the influence of the change of the power temperature coefficient of the component and the weak light response of the photovoltaic cell, which ultimately leads to the calculation result less than the actual value. In order to reduce the error in the calculation of PRstc, the mathematical relationship between PR and power loss of photovoltaic power station is discussed. The calculation method of power loss caused by the change of environmental factors is proposed, and the PRstc is calculated by using the variation. Finally, the PRstc is calculated according to the actual operation data of photovoltaic power station, and compared with the calculation method of industry standard NB / T 10394-2020. The results show that when the total irradiation dose is high, the difference between the two PRstc values is less than 2 %. When the total irradiation is low, the calculation result is larger than that of the standard method, and the difference between the two increases with the decrease of the total irradiation. Due to the consideration of the change of power generation caused by the characteristics of photovoltaic modules, the error caused by the change of power temperature coefficient and weak light response of modules is reduced, which is more advantageous than the calculation method of industry standard.