NED University has developed a PV testing LAB in collaboration with PV Lab Pakistan (Bahawalpur) under ASURE Centre. PV testing lab NED UET is a specialized test lab with focus on Quality Assurance and Risk Evaluation for PV modules. PV modules are evaluated in small and large samples directly from production lines, with special focus on their technical performance and reliability throughout their service life cycle. NED University has provided a space in Automotive Engineering Department. This lab is providing the testing facility to industry, commercial consumers, and government institutions.

The aim of the testing facility is to build the confidence of the consumer that the reliable and energy efficient equipment is reaching to the market through standard compliance checking.



                                                                                           Figure 1: PV Testing Lab


Following tests are being performed on PV modules:

  1. Power at STC (Standard Test Conditions)
  2. Power at low irradiance
  3. Electroluminescence (EL) Test
  4. Wet-leakage test
  5. Hot Spot Test (4 stages)
  6. Thermal Test
  7. Potential Induced Degradation (PID)
  8. Peel-off test
  9. Light Induced Degradation (LID) Test
  10. EVA cross-linking
  11. And others
  12. Details of individual tests are as follows:


Power at STC (Standard Test Conditions)

Panel manufacturer claims maximum power output at standard testing conditions (STC). This number is a baseline for design of all solar farms. PV Lab operates a Class AAA sun simulator for conducting all its power tests. Solar simulators are classified in accordance with IEC 60904-9. Low level of uncertainty is only possible when Class AAA simulator is used. This test is crucial to draw solid conclusion and serves to validate modules performance as claimed by the manufacturer.


Wet-leakage test

The test measures insulation resistance between the inner circuit and a water bath module is placed during testing. This test is relevant from a safety viewpoint.


Hot Spot Test (HS)

A thermographic camera is used to capture thermal images of a module. These images can reveal defects at soldering points, inactive regions in cells and formation of Hot Spots due to defective bypass diodes which can lead to irreversible damage to the module.



                                                                                         Figure 2: Setup for STC Test


Electroluminescence (EL)

Electroluminescence is a diagnostic process in which a camera capable of detecting near-infrared light is used to take image of a module. This procedure reveals a wide range of module defects, from casting the ingots to damage caused during transport. Electroluminescence is used for quality assurance during the manufacturing of the modules to find micro-cracks. These tiny cracks in the cells can lead to electrical insulation across entire segments of the panel. EL measurements are useful when conducting incoming goods inspections at the building site. Damages in the form of micro-cracks arising from transportation and rough installation processes are among the greatest risks for PV.



                                                                                                      Figure 3: Setup for EL Test

Potential Induced Degradation (PID)

Potential induced degradation, or the voltage dependent ageing of photovoltaic modules, is a type of power degradation that generally appears on the negative side of the module string and can affect almost any type of photovoltaic module.  Power loss from PID effect must be minimum and a power loss of 5% should not be exceeded in measurements before and after this period.



                                                                                                      Figure 4: Setup for PID Test


Peel-off test

This test aims to measure the adhesion of the bedding material (generally EVA) to glass. The peel-off test is valuable, because a peel-off force that is too low can indicate either that the production process was carried out with non-optimal parameters, or that materials past their expiry date have been used.



                                                                                        Figure 5: Peel Off Test

EVA cross-linking

The EVA cross-linking test determines what percentage of the transparent bedding material can be released using a solvent. The remaining portion is then termed the crosslinking level. If the level of cross-linking is too low, it can be an indicator of an increased risk of delamination, which can ultimately lead to failure of the module.


[1]. Quality assurance for PV modules -the German experience (By PV Lab Germany).

[2]. IEA: “Review of Failures of Photovoltaic Modules”, Task 13 external final report, IEA-PVPS, March 2014.