IEC 62782 pdf download.Photovoltaic (PV) modules – Cyclic (dynamic) mechanical load testing
1 Scope
This technical specification provides a test method for performing a cyclic (dynamic) mechanical load test in which the module is supported at the design support points and a uniform load normal to the module surface is cycled in alternating negative and positive directions. This test may be utilized to evaluate if components within the module including solar cells, interconnect ribbons and/or electrical bonds within the module are susceptible to breakage or if edge seals are likely to fail due to the mechanical stresses encountered during installation and operation. This test can be performed at any module temperature within the normal operating temperature range. Since the results have been determined to depend on the module temperature during the application of the load it is critical to maintain the module at a constant temperature during the performance of this test. This technical specification has historically been applied to rigid modules. It cannot be applied to flexible modules unless they are designed to be mounted in a rigid manner. In which case, the cyclic (dynamic) mechanical load test can be applied to the flexible module in its rigid mounting system. This test has been written as a standalone technical specification, but it is likely to be used in conjunction with other test standards. Typically, this test itself will not result in power loss, but when followed by additional stress tests like thermal cycling and humidity freeze, the damage done by the mechanical cycling results in power loss that would not have occurred due only to the thermal cycling and humidity freeze tests. For example, the transportation testing procedure (IEC 62759) includes the requirements for such a cyclic (dynamic) mechanical load test followed by 50 thermal cycles and 1 0 humidity freeze cycles.
4 Apparatus
The apparatus for this technical specification include: a) Equipment for performing the cyclic (dynamic) loading: this equipment shall be capable of applying a uniform load of 1 000 Pa ± 1 00 Pa onto the module surface in both directions to simulate pressure and tensile loads at a rate between 3 and 7 cycles per minute. The prescribed load is of uniform pressure, P, and is most appropriately applied with a pressure of air or vacuum. If a piston system (or other non-uniform application) is used to load the module, the force each piston (or applicators) exert is F = PA/n, where A is the area of the module and n is the number of pistons. To ensure a similar effect to the module, the maximum, perpendicular, center-to-center distance between evenly loaded points shall be 20 cm or less. If one piston consists of multiple loading points this maximum distance refers to both the loading points within and between pistons. The maximum perpendicular distance between the module frame and an evenly loaded point shall also be 20 cm or less. b) Means for monitoring, throughout the test, the continuity of the internal circuit of each module. c) Means for monitoring the temperature of the module to an accuracy of ±2,0 °C and repeatability of ±0,5 °C. The temperature sensors shall be attached to the front or back surface of the module near the middle without interfering with the cyclic loading. d) Infrared (IR) camera and a constant current power supply capable of providing between one and two times the Standard Test Condition (STC) maximum power current of the module in the forward direction. (See future IEC TS 60904-1 2.) e) Electroluminescence (EL) equipment and a constant current power supply capable of providing between 0,1 and 1 times the STC short circuit current of the module in the forward direction. (See future IEC TS 60904-1 3.) The IR and EL systems do not have to be capable of observing the module while it is under test.
IEC 62782 pdf download
