Anomaly Detection of Grid Connected Photovoltaic System Based on Degradation Rate: A Case Study in Malaysia

This paper presents the characterization and performance of six-year field data for two different systems of PV module technologies from the rooftop grid-connected system installed at Universiti Teknologi MARA (UiTM) Shah Alam. Two different PV module technologies are used as case studies to establish a method of anomaly detection on the system performance. The selected parameters such as string voltage, string current and AC power output are used in the analysis, while solar irradiance and module temperature are used as a reference basis. Based on the results obtained, both systems having degradation rates differently. System A had shown stable performance before it degraded by 16.09% after the 4th-year of operation, whereas system B continuously decreased by 39.35% during the monitored period. However, the string current of system A degraded up to 4.4% and, interestingly, no degradation for the string voltage. In contrast, system B has experienced a degradation of the string current by about 21.6%, whereas the string voltage was around 16.16%. Therefore, the string current and string voltage could identify the cause of the degradation rate of AC power. This analysis could be used to diagnose and identify the sources and causes of power degradation of grid-connected PV systems so that further action could be taken.