IEC 62938-2020 pdf free download

IEC 62938-2020 pdf free download.Photovoltaic ( PV ) modules – Non-uniform snow load testing
Modules photovoltaiques ( Pv ) -Essais de charges de neige non uniformes.
7.7.4 Procedure
The module to be loaded is mounted on the test bench as specified in the instruction manual of
the supplier Installations with clamping along the long frame side usually use cross bars as the
substructure . Bending of the module under load may cause the backsheet to touch the
substructure . This real condition shall be represented in the test set-up ( no free bending on the
test bench , if in reality such bending is prevented by the sub-structure
The environmental conditions for performing the tests are 25’C + 5 ” C
As most adhesives will perform worse under elevated temperatures , room temperature is
considered to be a worst case condition for testing . If the adhesive used for a particular module
type is known to perform better at room temperature , the test shall be performed at C + 5’C
The test procedure shall be as followed ( see also Figure 4 ) .
Apply an initial load of Sk = 2400 Pa for at least 24 h . After these 24 h , three cases are
distinguished
Case 1 : no movement in the frame is visible since the initial setting . The load shall be
increased to the next load step for at the least 30 min . Once no movement is visible for at
least 15 min , the load shall be increased further . Repeat this procedure until the module
fails . Then start with next module with the initial load
Case 2 : the deflection over time graph ( see Figure 5 ) shows a change in gradient within the
24 h but is stable for at least 15 min towards the end . If no movement is visible for at least
15 min , the next load step shall be applied for at least 1 h . Repeat this procedure waiting at
least 1 h for stabilization for each load step and 4 h for each 5th load step , until the module
fails . Then start with next module with the initial load
Case 3 : movement in the frame is still visible . Wait until movement stops . If no stable
situation arises and the module fails , the test series shall be stopped . If no movement is
visible for at least 15 min , the next load step shall be applied for at least 1 h .IEC 62938-2020 pdf free download.