Amongst the monitored parameters were: DC/AC voltages, DC/AC currents, AC power, cumulative AC energy supplied to grid, daily AC energy production; and meteorological parameters: e.g. plane-of- array (POA) irradiance, wind velocity, ambient temperature and PV module temperature. The system is appraised using performance indices such as array yield, final yield, PV module and system efficiencies, inverter efficiency, performance ratio, array capture losses and system losses.
The daily and monthly array yields are calculated as follows