One Year Round Robin Testing of Irradiation Sensors - Measurement Results and Analyses

The objective of this evaluation is an analysis of different, calibrated and commercially available irradiance sensors, to give a decision matrix with deficits or advantages for the application of each single sensor. Basis for this assessment is a Round-Robin-Test (RRT) with two identical experimental setups located at sites in Germany (Fraunhofer IWES Kassel and University of Applied Sciences Munich). The evaluation started at the end of the year 2007 with 18 irradiance sensors on each test arrangement and meanwhile provided over one year of operational experience. The sensor functionality and the measuring data of the sensors in their instantaneous values, daily, monthly and annual energy sum values are regarded. The measured data base helps to compare sensors of different and matching technologies under similar field conditions (diurnal variations at different locations and under specific weather conditions). In awareness of the operational behaviour of PV-systems (different technologies in certain weather situations), the relation to the operational experience of the irradiance sensors shows interesting aspects on the quality of system performance statements.