Testing and inspection of photovoltaic plants

DNV has the expertise, equipment and unique position in the industry to ensure, as an independent entity, the quality of the photovoltaic modules at all stages of the project.

Due to the high number of photovoltaic panels required for the construction of new solar plants, cases have been observed where the final quality of the product is not as expected. This may be due to manufacturing defects, transport or handling problems, incorrect installation or inadequate maintenance. For this reason, verification and inspection services in solar photovoltaic plants are essential to ensure the quality of the modules and check their performance. This is especially relevant during the construction and development phases of the project, as well as in the subsequent operation. The main purpose of these services is to facilitate effective management of possible deviations from the expected performance of the plant, thus ensuring maximum return on investment.

DNV provides a variety of verification and inspection services in solar energy using a wide selection of test methods and testing technologies. DNV's independence from any manufacturer of photovoltaic modules or other equipment guarantees impartiality in our services.

Services can be grouped into the following phases:

  1. Pre-construction phase services: prior to module manufacturing. They focus on the review of contracts, suppliers and technologies by independent experts:
    • Technical review of module technologies on the market
    • Support in supplier selection processes
    • Contract reviews (supply, subcontractors, manufacturing, construction, start-up...).
  2. Pre-shipment phase services: carried out at the factory, typically in China. Their objective is to detect manufacturing defects before shipment:
    • Pre-inspection of the factory and during the production process
    • Testing of manufactured modules. These services include the following tests at the client's request:
      • Non-Destructive (Visual inspections, Flash tests, IV Curves, Electroluminescence (EL), Bifacial coefficient)
      • Destructive (LID, PID, LeTID, Peel-off, Wet leakage, EVA gel content, Hot spot, Thermal cycle)
    • Inspection of container loading.
  3. Services on site at photovoltaic plants (Post-shipment): these services are carried out after transport from origin to where the client requires it, whether at the plant, destination port or any other location. The following tests are included at the client's request:
    • Visual inspections
    • Flash tests or maximum power tests: these measure the module's output power under STC conditions
    • IV curves: analysis of electrical behavior, possible degradation problems and performance under operating conditions
    • Electroluminescence (EL): these allow the detection of internal defects in photovoltaic modules with high resolution, such as breaks/microcracks in cells, short-circuited cells
    • Electrical insulation tests (HIPOT): evaluation of the integrity of the insulation of the module and its components. Helps to detect leakage currents
    • Infrared thermography: using high-resolution portable or aerial cameras (typically drones) with which hot spots, shadows or soiling can be detected.

DNV PV Mobile Lab

For post-shipment testing, DNV has a mobile laboratory which uses a state-of-the-art LED solar simulator (A+A+A+) and high-resolution electroluminescence testing equipment of up to 30 MPixel to provide highly accurate measurements and results that can be verified against international standards.

 

This laboratory can test more than 200 photovoltaic modules per day with an uncertainty of less than 3%. Due to its characteristics, it is capable of testing modules of up to 1400 x 2700 mm of different types (high efficiency crystalline modules, bifacial modules, thin film modules and PERC or HJT solar cells). In addition, the Mobile Solar Laboratory is equipped to perform electroluminescence tests with high or low current (EL) and bypass diode testing.

All these post-shipment services are typically carried out at the following project milestones:

  • Post-shipment tests: these can be carried out at the plant or at the port to detect possible defects due to transport. Used to guarantee supply quality before the start of the EPC installation
  • Commissioning: inspections that guarantee an adequate level of quality in the installation of the modules before their energization
  • Inspections prior to the expiry of the warranty: in order to verify the condition and performance of the panels before the end of their warranty and to be able to make claims to the supplier
  • Tests in the operational phase: the objective of which is the early detection of faults or possible degradation problems in the modules. In this phase, the most used inspection technique is infrared thermography with a drone.

DNV is accredited as a testing laboratory under ISO 17025 by ENAC. We have been carrying out tests under a multitude of international standards in the renewable sector for over 35 years, making it clear that, as well as independence, the highest quality is one of our principles.

DNV is a world-renowned company with over 160 years of experience as an independent consultancy and certifying body. For over 20 years we have been present in the solar energy sector, offering consultancy, supervision, verification and high added value testing services.