An Analysis of Factors Affecting the Variation of Performance Ratio in a Medium-Scale Solar Photovoltaic System Over a Six-Month Period

Santipap Suksavut — 2025-09-05

This research aims to analyze the performance ratio (PR) of a utility-scale solar photovoltaic system based on six months of operational data collected from October 2024 to March 2025. The study utilized actual field data from a 358.80 kWp PV system at the power distribution center in Udon Thani, Thailand. The daily weather-corrected performance ratio (PRact) was calculated using the energy injected into the grid (Egrid) and global solar irradiation (Hi). The results were then analyzed for monthly trends. The findings revealed that the average PRact ranged from approximately 72.4% to 81.2% across the observed months, with the lowest value in February. A significant improvement in PRact was observed after a panel cleaning event on February 24, 2025, indicating that soiling had a substantial impact on system efficiency. When compared with the PVsyst simulation, which estimated an average PR of 81.11%, the actual values were closely aligned during certain periods, particularly in the early stages of the observation. These results suggest that ongoing PR monitoring, combined with appropriate maintenance strategies, can enhance system reliability and support long-term performance evaluation of utility-scale solar PV systems.

Defence Technology Academic Journal

An Analysis of Factors Affecting the Variation of Performance Ratio in a Medium-Scale Solar Photovoltaic System Over a Six-Month Period