Accurate Irradiance Measurement on Large Scale Photovoltaic System Application

Abstract

As the number of large scale photovoltaic power plants (which also known as solar parks) is growing in recent years, standard activities related to the system such as the operation and maintenance of the plant and grid management have become more crucial. In order to ensure a standard quality of these activities, accurate irradiance measurement is required. Due to the relatively wide area of a large scale solar park, the irradiance measurement would most likely be suffering from additional error induced by spatial variation. Therefore proper planning regarding the optimum amount of irradiance measurement devices and how these devices are arranged in a space is one solution to minimize the issue. A statistical model based on data interpolation, clustering, and searching concepts has been built in order to approximate the optimum irradiance measurement devices configuration on an actual solar park. The statistical model utilizes satellite-derived irradiance data as its main input. In return, the model estimates the measurement uncertainty for every additional irradiance measurement devices and also roughly approximates themost probable positions for the devices. The study case result shows that an imaginary solar park in Leipzig with a total area of 1.8 km2 can reduce its measurement uncertainty for about 4% by increasing the amount of irradiance measurement devices from 2 to 30. While in similar case, identical imaginary solar park built in Arizona is only able to reduce its measurement uncertainty by no more than 2%. It has also been shown that utilizing a dataset with 4 times less temporal resolution would lead to reduction of measurement uncertainty for a maximumof 1%. Instead of being uniformly distributed throughout the solar park, the model’s suggested positions for the measurement devices are concentrated on certain areas within the solar park. It is found that these concentrated areas are formed due to yearly spatial variations that occur within the particular region. In the end, it is hoped that the information provided by themodel can accommodate the need of some actors within the solar park industry with regards to how relatively large area of a solar park influences the accuracy of irradiance measurement.