Supervision of the energy performance of multi-arrays PV plants by means of bi-monthly violin plots

Small PV plants are frequently not equipped with a meteorological station, that is decisive to monitor the energy performance of a PV plant and to detect low-intensity anomalies, as premature ageing, before they become faults. The paper proposes a methodology for PV plant not equipped with a weather station and it is based on a violin plot, that is a statistical tool that integrate information from box plot and histogram. In absence of environment parameters, the monitoring is done, by comparing each other the energy performance of the arrays constituting the PV plant, that should produce the same environment condition affects all the arrays. The methodology is applied to a real 20kWp PV plant, studying the energy performance for different energy datasets.