ABSTRACT
Photovoltaic modules are usually installed on special ground or pole mounting structures. Modules may be mounted on rooftops provided that proper building and safety precautions are observed. For more output, modules are sometimes installed on a tracker-a mounting structure that moves to continually face the sun throughout the day. The performance of photovoltaic modules and arrays are generally rated according to their maximum DC power output under standard test conditions (STC). Standard test conditions are defined by a module operating temperature of 250°C, and incident solar irradiance level of 1000 W/m2 and under air mass 1.5 spectral distribution. Since these conditions are not always typical of how PV modules and arrays operate in the field, actual performance is usually 85-90 per cent of the STC rating.
