For each set of conditions (irradiance between 100-1100 W/m² in 100 W steps and temperature of 15, 25, 45, 50, 75 °C) according to IEC 61853-1, an I-V curve of PV module is measured. The temperature coefficient at 1000 W/m² is determined in addition from measurements between 15 and 75 °C in 1 K steps.
Additional to the accurate measurement of the power at STC, the behavior of the modules at different ambient conditions is important. For the power rating measurements, the modules are characterizedat different irradiance and temperature conditions. This accurate power rating measurements in accordance to the standard allows a comparison of the measured module type to other module types as well as to the current state of the art. Furthermore, power rating enables precise yield prediction for each location worldwide.