SOLAR PV INSPECTIONS
Electrical safety inspection
Infrared inspection of solar PV Panels quickly finds bad cells within a single panel or an entire array. Thermal imaging can also locate malfunctioning inverters and hot electrical connections. Defective PV cells reduce panel efficiency and can lead to a premature failure of the panel. Infrared inspection of photovoltaic solar panels is a 100% coverage, non-destructive inspection tool for finding bad cells in PV solar panels.
The inspection is conducted with the panels in operation, from the front side for roof-mounted panels or from the backside on elevated arrays. No down time is required for conducting the inspection and there is no interference with the production of power.
The electrical current flowing through the cells in a panel flows from positive to negative, cell to cell. When there is a defective cell somewhere in the string of cells, it can limit the current flow produced by the good cells. If there is enough voltage produced by the good cells, they can force the defective cell to operate in a “reverse bias” mode which forces it to carry the current in a reverse direction to its semiconductor design. When this happens, the power produced by the good cells is dissipated across the defective cell, turning electrical power into HEAT. Because the power is converted into heat within in the bad cell, it is not delivered to the panel’s output to do work, reducing the panel’s power output and efficiency.
A single PV cell in a panel is not designed to dissipate large amounts of amount of excess heat. Without the ability to conduct, convert or radiate the excess heat out of the cell, it gets very hot. This localized cell heating creates “hot-spots” which are visible to infrared and can get hot enough to cause secondary defects in the panel.
What a Thermal Image of a Solar Panel shows. The areas that are discoloured show potential failure.