On-site measurement of the performance of crystalline silicon PV arrays

A procedure for determining the rated power of crystalline silicon photovoltaic arrays from on-site measurements in the field is described. It is the outcome of several years' experience in the testing of European pilot and demonstration plants and has formed the basis of an IEC draft standard on the subject. The procedure differs significantly from that followed when measuring the rated performance of solar cells and modules. The reasons for these differences are explained.