IEC 62938-2020 Photovoltaic (PV) modules – Non-uniform snow load testing (IEC 62938:2020)

IEC 62938-2020 Photovoltaic (PV) modules – Non-uniform snow load testing (IEC 62938:2020). 5 Prerequisites The PV module type shall have passed the static mechanical load test (MQT 1 6) according to IEC 61 21 5-2 with a minimum positive test load of 5 400 Pa. 6 Testing 6.1 General These test specifications describe a test method for determining the direct load-bearing capability of framed PV modules under the effects of inhomogeneous snow loads. 6.2 Projections of the test results Failure of the (adhesive) bond between module frame and glass/laminate can lead to • deformation of the module rail or frame, • glass breakage, • displacement of rail or frame parts, • fracture of rail or frame parts, • loss of adhesion strength in adhesive bonds , and • breakage or displacement of mounting parts. In addition, this can impact electrical performance due to: • interruption of the module’s electrical insulation, • cell breakage and junction box failure, and • power degradation. 6.3 Test plan Figure 1 shows the test flow where the numbers in the boxes represent the test references in IEC 61 21 5-2. Five modules undergo the mechanical testing until failure as defined in Clause 8 occurs. A sixth module shall be used to determine the highest load bearing at which no power degradation > 5,0 % occurs. 7 Test procedures 7.1 Visual inspection This test is performed according to IEC 61 21 5-2 MQT 01 . 7.2 Maximum power determination This test is performed according to IEC 61 21 5-2 MQT 02 after initial stabilization according to IEC 61 21 5-2 MQT 1 9. For intermediate and final control measurements, further stabilization steps might be required dependent on the module technology. The maximum power determination is a relative measurement only; the measurements do not need to be performed at standard test conditions (STC). 7.3 Insulation test This test is performed according to IEC 61 21 5-2 MQT 03. 7.4 Wet leakage current test This test is performed according to IEC 61 21 5-2 MQT 1 5. 7.5 Humidity-freeze test This test is performed according to IEC 61 21 5-2 MQT 1 2. 7.6 Electroluminescence imaging Accompanying the visual inspection, electroluminescence according to IEC 60904-1 3 imaging could be performed optionally on the electrical verification module to visualize cell cracking. 7.7 Non-uniform snow load test 7.7.1 Purpose This test specification describes a method for determining the direct load-bearing...