Failure diagnosis of short- and open-circuit fault conditions in PV systems

Accurate and consistent performance assessment of photovoltaic (PV) systems with the use of advanced failure diagnostic tools is essential to safeguard high levels of production. The scope of this work is to propose a failure diagnostic approach capable of diagnosing short- and open-circuited PV modules in grid-connected PV systems. The developed failure diagnosis approach comprises of a failure detection and a classification stage and requires as input features the acquired in-plane global irradiance, ambient and module temperature and PV operational electrical measurements. In particular, the failure detection stage was based on a statistical comparative assessment between the measured and simulated dc power, while the failure classification procedure was based on the ratio between the measured and simulated dc voltage and current. The diagnostic approach was validated experimentally using field measurements of a PV system installed in Cyprus. The obtained results demonstrated that the developed methodology can detect and classify short- and open-circuit fault conditions in PV systems. More specifically, the failure diagnosis rates, obtained when emulating 100 failure signatures imputed to the yearly acquired performance time series data of the test system, were 98.6 % and 99.8 % for short- and open-circuited PV module failures, respectively.