Inverter undersizing in PV systems

The choice of nominal power of the inverter should be based on the operational power of the PV array, rather than on the nominal power of the PV array. If an inverter is chosen too small, power limitation loss will occur at high irradiance levels when the available array power is limited by the inverter´s nominal (maximum) input power. If an inverter is chosen too large unnecessarily high investment costs are needed. A graphical tool for inverter sizing in The Netherlands was constructed, based on irradiation measurements on a 10-seconds time scale in Petten. It was shown however that the irradiation distribution over The Netherlands is such that this graphical tool cannot be used for all locations in The Netherlands. System designers are advised to use their own simulation tools, based on hourly calculations, to determine the optimum sizing factor for the given PV system. To account for the peak-shaving effect of the applied time steps of one hour, the resulting sizing factor should be divided by a factor of about 1.07 for Northern European locations (sea climate).