This part of IEC 62446 defines outdoor thermographic (infrared) inspection of PV modules and plants in operation. The inspection can include cables, contacts, fuses, switches, inverters, and batteries. This inspection supports the preventive maintenance for fire protection, the availability of the system for power production, and the inspection of the quality of the PV modules. Included in this document are the requirements for the measurement equipment, ambient conditions, inspection procedure, inspection report, personnel qualification and a matrix for thermal abnormalities as a guideline for the inspection.
This document defines outdoor thermography on photovoltaic (PV) modules and Balance-of system (BOS) components of PV power plants in operation, using passive techniques (standard system operating conditions under natural sunlight, without any external power or irradiation sources). IEC 60904-12-1 covers general methods for laboratory or production-line PV module thermographic imaging but not the specific details that are most relevant to outdoor imaging of operational power plants including BOS components.
Two different levels of inspections are currently used:
a) A simplified thermographic inspection. This is a limited inspection to verify that the PV modules and BOS components are functioning, with reduced requirements for the qualification of personnel. For example, during a basic commissioning of a PV plant.
Authoritative conclusions regarding module quality are not possible with this inspection, and examples of abnormalities are provided to aid the inspector.
b) A detailed thermographic inspection and analysis. This may include thermal signatures which differ from the examples provided, and therefore requires a deeper understanding of the thermal abnormalities. For example, it may be used for periodic inspections according to the IEC 62446 series and for trouble-shooting the cause of underperforming systems.
Absolute temperature measurements may be made. An authorized expert in PV plants, together with thermography experts can perform the inspection.