Wind Load: Task Group 7

Task Group 7 focuses on potential international standards that provide a test method for evaluating the effects of non-uniform wind loads on photovoltaic (PV) modules and their mounting structures. The purpose is to develop a wind-load test method to evaluate safety issues for modules and fixed parts caused by wind and installation conditions.

The wind-load test may be utilized to evaluate whether  components within the module, including solar cells, interconnect ribbons and/or electrical bonds, are susceptible to breakage or if fixed parts (e.g., brackets, clamps, screws, fixed holes) are likely to fail due to the nonuniform mechanical stresses encountered during strong wind load.

This test shall be written as a stand-alone document, but it is likely to be used  with other test standards where application of multiple stresses may cause degradation not observed with a single stress. For example, it may be combined with the International Electrochemical Commission’s (IEC’s)  static mechanical load tests (IEC 61215-2:2016) and dynamic mechanical load tests (IEC TS 62782:2016).

This standard may specify test levels referring to mean surface pressure pattern required for nonuniform wind load testing, and shall consider the environmental conditions such as those shown below in Figure 1, including wind velocity (Vmax = 61.2 m/s), wind directional angle (β = 0°, 180°), and module tilt (α = 10°, 20°, 30°, 40°). Furthermore, this standard may specify the requirements of a nonuniform dynamic mechanical load system. For more information, see Environmental Factors for Non-uniform Dynamic Mechanical Load Test due to Wind Actions on Photovoltaic Modules, Non-Uniform Wind Loads Test for Photovoltaic Module, Evaluations of Wind Effect on PV Module by Non-uniform Mechanical Loads System and Mean-Surface Pressure Pattern.

This group originally focused on nonuniform wind loading on PV module, and IEC Technical Committee 82 WG2 is discussing the Northern Wind Innovation Programme’s proposal for such wind loading (see Figure 2 below).

In February 2020, TG7 team (see Table 1) has owned forty-six PV experts who come from eight countries and thirty-one companies (or universities or institutes). Currently, TG7 is discussing a new test procedure to evaluate the effects of non-uniform wind loads on PV modules and their mounting structures. This work is to propose a new wind-load test method to clarify the safety or performance issues, for PV module and its fixed parts, caused by wind and installation conditions.

In order to fulfil the standardization work, TG7 has addressed one draft about non-uniform wind load test and made a report in IEC TC82 WG2 standard meetings in 2019. This test may be utilized to evaluate if components within the module including solar cells, interconnect ribbons and/or electrical bonds are susceptible to breakage or if fixed parts (such as aluminum extrusion structure, bracket, fixture, screw, etc.) are likely to fail due to the non-uniform mechanical stresses encountered during strong wind load. No fixed parts should be deformed or separation under the test state of stress. In order to meet the requirements for different wind velocity, this standard specifies three types of wind velocity (BS = 13, 15, 17) in terms of their test data named mean surface pressure pattern (MSPP) required for non-uniform wind load testing. In addition, the other environmental conditions like wind directional angle (β = 0°, 180°) and module tilt (α = 10°, 15°, 20°, 25°, 30°, 35°, 40°) are also considered. For more information, see (NWIP) Photovoltaic (PV) Module – Cyclic (Dynamic) Non-uniform Wind Load Testing.

Furthermore, one round-robin test is being estimated in TG7 to define the specific test condition about the type of module, mounting hardware, support structure, and many other details. In coming future, this test could be written as a standalone document, but it is likely to be used in conjunction with other test standards where multiple stresses may cause degradation not observed with application of mechanical load test. For example, the static ML (IEC 61215-2) and DML (IEC TS 62782) testing procedure do not include the requirements for such a non-uniform wind load test.

Table 1 TG7 Team (2020-02)

Progress Update

For a Task 7 team list and meeting schedules and minutes, login to the pbworks website. You may request to the Task 7 team area on your first visit there.

Related Resources

Environmental Factors for Non-uniform Dynamic Mechanical Load Test due to Wind Actions on Photovoltaic Modules
Authors: Hsu, S.-T., Lin, W.-Y., & Wu, S.-J.
Journal: Energy Procedia,

Non-Uniform Wind Loads Test for Photovoltaic Module
Authors: Hsu S.-T, Lin W.-Y, Hsieh, C.-F
Conference: EU-PVSEC (2019)

Evaluations of Wind Effect on PV Module by Non-uniform Mechanical Loads System and Mean-Surface Pressure Pattern
Authors: Hsu, S.-T, Lien, C
Conference: WCPEC-7 (2018)

(NWIP) Photovoltaic (PV) Module – Cyclic (Dynamic) Non-uniform Wind Load Testing

Task Leader

Shu-Tsung Hsu (Anderson) – Industrial Technology Research Institute of Taiwan