The PV Module Testing (PVMT) Group at SERIS offers testing and certification of PV modules to customers from the PV industry. The PVMT Laboratory is accredited since 2012 to the esteemed ISO/IEC 17025 certification standard and is currently working on expanding the accreditation to reliability and safety tests. In addition to standard testing, we also investigate other PV degradation modes that occur in the hot and humid climate of South-East Asia, thus allowing us to become the reference test centre in supporting the industry needs in the region. Such research testing includes fast indoor NMOT determination, PID testing in a salt mist environment, and PID degradation and recovery studies. The specialised services offered by the PVMT Group can be summarised as “SOLAR STEPS”, see the graph below.
Equipment available at the PVMT Laboratory
The PVMT Group performs R&D, customised and certification testing in accordance with the international qualification and type approval standard IEC 61215 and safety standards (IEC 61730 and UL 1703). We are well equipped with industryready test resources and constantly renew and upgrade our key equipment.
SERIS uses the proven Pasan SunSim 3B and the latest HALM long-pulsed sun simulator to characterise test samples as small as 1-inch cells to full-size modules of c-Si and thin-film technologies.
Each flasher system has an integrated temperature enclosure for testing at various temperatures, including the standard test condition (STC), thus allowing the indoor measurement of temperature coefficients. Neutral filters are also available for low and high irradiance measurements.
We pride ourselves for being accredited under ISO/IEC 17025 for golden module or high-precision measurements for largearea c-Si and CdTe modules.
With Class-B continuous light sources, we perform module stabilisation, hot-spot endurance tests and standard compliant temperature tests.
Light soaking is necessary to stabilise the modules against light induced degradation (LID).
Hot-spot endurance testing is essential to identify the weakest cell locations in the worst shadowing conditions. Such information will help to improve the manufacturing process of solar cells and modules.
The UV preconditioning test is an ageing test aiming to identify any susceptibility to UV degradation. The module under test is irradiated with at least 15 kWh/m2 to as high as multiple runs of 60 kWh/m2 in total UV irradiation within the 280-350 nm wavelength range. In a typical certification test flow, the tested module is then checked against damages (visual inspection, insulation, wet leakage, electrical characterisation if required).
Insulation test, wet leakage current test, impulse voltage, reverse current, insulation thickness check: all these tests are performed to assess the electrical insulation resistance of a module.
The insulation test is a “dry test”, aiming to assess module electrical insulation between active parts and accessible parts. A voltage of either 500 V or the maximum system voltage (whichever is greater) is applied to the module for 2 minutes and the insulation resistance is measured.
The wet leakage test is designed to assess the module’s electrical insulation in a “wet” environment, to verify that moisture from rain, fog, dew or snow does not enter the active parts of the module, and is thus particularly relevant for the tropics. The test is carried out essentially as for the insulation test, except that the module is tested while immersed in a water solution of given resistivity.
Both tests act also as “control tests”, as they are often performed after many of the other stress tests listed below.
Our comprehensive suite of mechanical stress tests covers the following industry standard tests:
Climate chambers are the workhorses in reliability and durability testing. Tests such as damp heat, thermal cycling, humidityfreeze, hot and cold conditioning with PID options require the use of such equipment to vary the temperature and humidity in a controlled way over a wide range of conditions.
The tests are usually run in batches of up to 12 modules, to maximise throughput and minimise costs. The uniformity of the temperature and humidity within the chambers is tightly controlled, allowing accurate assessment of the degradation mode to be studied.
Using electroluminescence (EL) imaging, infrared (IR) imaging and resistive measurement techniques, coupled with our scientific knowledge and experience, we support customers via recommendations of possible root causes for design weaknesses and faults.
We also assess the optical characteristics of the module under test for both spectral responsivity measurements and spectral mismatch correction, providing best-in-class precision in the electrical measurements.
All electrical, optical and mechanical aspects of PV modules can be characterised at our laboratory. Through detailed analysis of the measurements, we can ascertain the likely root cause and allow customer speedy response to any faults arising.
Our location in the tropics makes the PVMT laboratory an ideal location to conduct extended testing relevant to South-East Asia. Specifically designed tests include:
In 2016, the IEC 61730-2 standard was strongly revised. The PVMT laboratory is updating the procedures and (where needed) the equipment to fulfil the new requirements. As an example, the photo shows the carriage used in the cut susceptibility test, to assess whether the PV module still meets the insulation requirements after defined cutting of the backsheet.
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