Online Fault Diagnosis, Classification, and Localization in Photovoltaic Systems

Owing to the consumers' growing tendency to solar energy, monitoring and detecting possible faults in the photovoltaic (PV) systems are very important. Since common protection systems are not able to detect faults in PV systems, many approaches have been proposed to detect faults and increase system reliability. In this article, various states of faults occurring in PV systems, e.g., partial shading fault (PSF), line-to-line fault (LLF), including intrastring (IS) and cross-string (CS), open circuit fault (OCF), and combinations of these faults, such as hybrid faults, are investigated. Moreover, the characteristic curve of PV systems for different faults is delineated, and the mathematical equations for the extreme points of each curve are presented in order to study the effect of various faults on power-voltage (P-V) curve, comparing them with the healthy mode. The obtained results were used to present an algorithm based on the definition of the fault indexes for identification, diagnosis, and localization of the faults. The effect of maximum power point tracking (MPPT) was considered in the process of fault detection, and finally, different scenarios of faults were considered in simulation and experimental cases to validate the suggested algorithm.