AES: O&M Planning Considerations

AES: Advanced PV Diagnostics: Thermal Imaging on PV

Thermal imaging has many uses in PV system O&M, both for preventive maintenance and as a troubleshooting tool. The fundamentals of thermography are the starting point; from there applications include imaging of terminations to look for high resistance and overheating, inspection of electrical equipment, and troubleshooting, followed by guidance from existing standards on how to respond to issues that are found.

Unique to our industry is using thermal imaging to inspect PV modules. Information can be obtained rapidly, and in fact aerial thermography – either via drone or human-piloted aircraft – has become a preferred means of inspecting PV arrays on large systems, dramatically reducing the time spent on the ground trying to find issues through other means. Hand-held use, while difficult at a large scale, is particularly useful for pinpointing issues and troubleshooting. Typical failures and their heat signatures are a key takeaway, as well as recommended actions based on severity.

AES: Advanced PV Diagnostics: I-V Curves

I-V curves are the basic graphical representation of performance of PV cells, modules or strings: measuring them can allow for insights into performance issues that are difficult, if not impossible, to see with other means. While field-use of I-V curve tracing has been in decline, it is still commonly used and – even if you never use an I-V curve tracer –  being able to "think like a module," will help you immensely in troubleshooting, determining the root cause of issues spotted through other means, and in understanding why PV "acts" the way it does.

This lesson starts with the basics of I-V curves, addresses field use of tracers, and quickly builds to an advanced discussion of good, bad, and ugly curves, what they mean, and what causes them. This is critical information for the well-rounded O&M professional.