The owners of a solar farm in Sussex required a cost-effective and time-efficient solution for ongoing solar PV module tracking and analysis, thus reducing the need for constant Operations and Maintenance (O&M) site visits.
We were asked us if we could provide a more robust survey and effective health and safety management solution on an ongoing basis moving forward.
The challenges we faced at the site were the solar farm location, near a busy airfield and several high-voltage overhead power cables (up to 400,000 volts) running directly over many solar PV arrays.
After mitigating the risks, maintaining direct contact with local Air Traffic Control (ATC) and accurate planning of the overhead power cables we were able to provide a time-effective and safe solution to the owners for the routine inspections.
The solution we have provided is to carry out regular inspections using drones carrying two cameras; normal and thermal/infra-red. Aerial Thermography. With additional image tagging using onboard GPS, for tracking individual solar PV module coordinates which can be used by the O&M during maintenance post-survey.
Aerial Thermography allows us to “see” solar PV anomalies not detected with the human-eye; Hot-spots, bypass diodes, open-strings and individual PV failures thus reducing solar energy generated electricity by the arrays or even failure of multiple arrays.
The initial aerial inspections resulted in reporting several open-strings, hot spots, bypass diodes, areas of new shading, of which we were able to provide detailed imagery with precise locations of the failed or pending failures using the GPS coordinates recorded by the drones. The imagery also resulted in finding damage caused from the solar farm build several years prior, undetected until the thermal analysis. Quality assured using level 2 and level 3 certified thermographers.
All reports and dual camera imagery were recorded and stored securely in the cloud for the O&M. This has resulted less frequency of O&M visits due to the use of our drone technology and aerial thermography.
With ongoing visits throughout the year, we are able to save, create historic data and monitor pending or less severe solar PV anomalies, thus more time-efficient and cost-effectiveness to the customer.
Drone Thermography Background
Drone thermography is a non-destructive diagnostic technique based on the use of special cameras sensitive to infrared rays, called thermal cameras. The purpose of thermography is to measure the surface temperatures of any visually accessible subject.
The possibility of “visualising” the thermal state of a body by simple framing makes this technique particularly suitable in terms of safety, energy saving, maintenance control and non-destructive controls in general. In fact, thermal anomalies are almost always the manifestation of other anomalies that are more difficult to detect.
Thermography makes it possible to diagnose these anomalies in a very short time, without interacting with the object of measurement and therefore in conditions of maximum safety. Naturally the measurements must be adequately interpreted by expert personnel.
In addition, we can provide a broader solution, via our Partners, that the site is not only observed but also maintained. This includes maintenance of the grass area (so as not to obstruct or ingress the infrastructure) and to carry out reparations/maintenance of the infrastructure itself. We are always happy to provide and recommend our Partners to deliver this fully rounded solution as an option.
The pre-planning for safety and information capture, drone specifications, flight operation and post flight analysis all form the package that we offer to meet the requirements.
This approach has resulted in significant reduction in resource costs, pre-empting outage risks and rapid response to fix issues. The work is ongoing, and all reported back in agreed formats as specified by the customer.
