Temperature testing and analysis of PV modules per ANSI/UL 1703 and IEC 61730 standards

The photovoltaic (PV) modules exposed to the sunlight under typical field conditions experience much higher temperatures than the ambient temperatures. In the hot climatic conditions such as Arizona, the module temperatures could reach as high as 85°C to 95°C depending on the mounting and operating configurations. In the worst case scenarios such as partial shading of PV cells of air gap free rooftop modules, some of the components might attain high enough temperatures that could compromise the safety and functionality requirements of the module and its components. Currently, two module safety standards are extensively used: IEC 61730-2 (international) and ANSI/UL 1703 (United States). These standards provide procedures to determine the maximum reference temperatures of various components and materials of a PV module. This paper presents and analyzes the temperature test results obtained on 9 different components of a PV module: front glass, substrate/backsheet (polymer), PV cell, j-box ambient, j-box surface, positive terminal, backsheet inside j-box, field wiring and diode. The temperature test results of about 140 crystalline silicon modules from a large number of manufacturers who tested modules between 2006 and 2009 at ASU/TUV-PTL are analyzed under three test conditions: short-circuit, open-circuit and short-circuit and shaded.