Parameters estimation and curves analysis for faults evaluation of a degraded photovoltaic module

In the present work, a fault evaluation method for photovoltaic arrays based on fault parameters identification and curves analysis is proposed for diagnosing the state of photovoltaic generators. An overview of the components, the modelling of the photovoltaic generator and the meaning of the parameters is established for relating parameters to photovoltaic components and environmental conditions. The analysis and investigation of the relationship between the maximum power points and the parameters variations are performed. Investigation on how degradations and failure on photovoltaic systems can affect parameters, is established. In this context, the methodology for diagnosing and monitoring defects based on photovoltaic estimated parameters is developed; the optimization technique maximum likelihood, is used for extracting health and faults parameters from the measured curves of the photovoltaic array. From residual vectors, the parameters which vary more are the series resistance, the shunt resistor, and the current of photon. The maximum power also changes and decreases from its reference value. The validation results prove deviations on parameters, which means that there are degradations and failures on the ARCO Solar M75 array after 20 years of outdoors operation. So, at the end of this analysis, it is recommended to act on the PV system through junction box, cell edges, wiring, busbars, and connectors.