Temperature-corrected Performance Ratio of Grid-Connected Photovoltaic System: Tropical versus Continental Climate

Performance ratio (PR) is often used as a performance metric in commercial acceptance tests of an installed grid-connected photovoltaic (GCPV) system. Recently, PR has been claimed to significantly affect seasonal and weather variations, which would invite unnecessary risk to the commercial acceptance test. In the updated IEC 61724-1, the temperature-corrected performance ratio (TCPR) has been included as the performance metric to remove the seasonal and weather variations. However, not all climate regions experience these variations, which means that TCPR might not be necessary for certain climate regions. Due to that, this study aims to analyse the relevancy of determining TCPR in addition to the normal PR for GCPV systems for different climate regions. The analysis was conducted using PVsyst software by comparing the PR and TCPR of two similar GCPV systems: case A represents tropical climate and case B represents continental climate. The results evidently show that the PR and TCPR values are always very close for both climate regions if analysed annually. However, when analysed monthly, the normal PR varied significantly between 77.5% and 90.0%, indicating a 12.5% difference for continental climate, but for tropical climate, the difference is just 1.0%. Conversely, the monthly TCPR variation in the continental climate is insignificant, with the value ranging from 81.4% to 84.1%, indicating only a 2.7% difference. Thus, the results of this study suggest that both PR and TCPR are relevant for continental climate. However, normal PR alone is already sufficient for tropical climate as the performance metric.