Development of a test station for accurate in situ I-V curve measurements of photovoltaic modules in Southern Norway

The development of an outdoor test station for accurate in situ I-V curve measurements of photovoltaic (PV) modules is described. The modules are installed in an open-rack configuration at the University of Agder in Southern Norway. Seven new and three aged PV modules of different type and make are being tested, including mono-and multicrystalline silicon from differing manufacturing routes, triple-junction amorphous silicon, and CIS. Data acquisition is controlled with a multichannel electronic load system and LabVIEW software, recording high-resolution I-V curves at one-minute intervals. Between I-V curve sweeps, each module is operated at the maximum power point. Characteristic electrical parameters are extracted and stored together with values of module temperatures and in-plane solar irradiance, the latter recorded at sub-second resolution. The paper describes the experimental set-up in more detail, discusses some local environmental effects, and presents a sample of test results.