Diagnosis of PV panels

When is the diagnosis of PV panels necessary?

In each PV power plant there are PV panels connected in series to individual sections. Thus each section forms an imaginary chain of panels; each chain is as strong as its weakest cell. In practice this means that one defective panel sets out of operation the other panels in the section or reduces their production at least. Due to a high resistance a damaged panel does not allow sufficient current flow; other panels adapt to this current and limit their power.

There are several guaranteed ways of how to reveal any defects.

Volt-ampere characteristics of PV panels

If there is an access to solar cables, measurements can be performed directly in the area of PV power plant. Therefore it is not necessary to remove and take PV panels away.

Measurements of PV panels’ parameters verify if the manufacturer guaranteed VA characteristics of PV panels, i.e. a dependence of current on panel voltage, correspond to reality.

Measurable parameters:

• Maximum power of PV panels
• Open circuit voltage
• Maximum power voltage
• Measurement of short-circuit current
• Measurement of maximum power current
• Calculation of efficiency

Electroluminiscence Crack Detection (ELCD) test

Thanks to this test we can reveal invisible material or manufacturing defects of your solar panels and their cells which affect the long-term production of solar panels. Especially microcracks have a significant impact on a long-term stability of performance parameters of photovoltaic panels. ELCD test can reliably detect cracks and rips in cells, detached contacts of strip bus. It also reveals missing or broken screen-printing grass strip and reliably detects dirts and impurities in crystalline silicon.

Examples of ELCD tests: