Objectives of the service
The solar photovoltaic energy market is showing an ever-increasing demand in the last years, which features the past and expected trend for the following years. The aforementioned growth of the photovoltaic solar market has as a consequence two key aspects: 1) the increase in the number of installations and 2) the increase in the average size of said installations.
This fact has as a consequence the need to analyse a huge amount of data for the thermographic inspections with the aim of detecting faults or incidences in solar cells and modules. The manual execution of this analysis, as it is mostly done to date, has serious disadvantages for customers mainly due to the following two aspects:
i. Very time-consuming activity: the installation will not be operating at its maximum performance for a longer period.
ii. Manual, tedious and repetitive tasks: it will lead to a large increase in the probability of making mistakes due to human factors.
This scenario calls for the development of means and procedures that optimize the thermographic data processing, with the consequent reduction in time, thanks to a high level of automation, the elimination of the human factor, and to machine-level accuracy.
Users and their needs
Our worldwide service is aimed at the main stakeholders of the photovoltaic sector around the world, such as: Engineering, Procurement and Construction (EPC) companies, PV asset owners, Operation & Maintenance (O&M) companies, etc.
To guarantee that our service meets our customer’s needs, ELECNOR (EPC, PV asset owner and O&M company), EXUS (EPC, PV asset owner and O&M company) and AEROTOOLS (O&M company specialized in drone-based thermographic inspections) companies have been involved in the project, from the definition of requirements, to the final validation of the service through the intermediate monitoring of project results. The main needs of our customers are the following:
- Precise fault detection, identification and location.
- Robust inspections against false positives.
- Reduction of the time required to obtain the inspection report.
As can be seen, the needs of our customers are very similar, although for different purposes. While PV plant owners are interested in the inspections results to solve incidences for having their installations working at its maximum performance for as long as possible, the purpose of having the same information for an insurance company is to deal with warranty claim situations.
Service/ system concept
Our service provides as output the corresponding inspection report (in digital and PDF format), containing information on the faults or incidents found in the cells, modules and strings of the PV asset. This information makes easier the decision-making for our customers regarding Operation & Maintenance actions.
Furthermore, thanks to automatic data processing, we are able to generate a large amount of relevant information for our customer. For this reason, we have developed a web-based user interface, which will allow them to carry out the exploitation of data in a user-friendly environment.
In order to achieve all of the above, it is necessary to process the input data properly through our automated tool. The processing chain for this tool is briefly explained below:
- Fault detection & classification: images captured with the drone, both RGB and thermal, will be processed and analysed using artificial intelligence algorithms, in order to detect and classify faults.
- False positive discrimination: using homography and image processing techniques, the pixel-level correlation of the images in both RGB and thermal spectra will be defined, to discriminate false positives.
- Fault location: through navigation and positioning techniques combined with drone's telemetry, the exact position of each detected fault will be identified.
Space Added Value
As a key aspect, our service is leveraged on Satellite Earth Observation and Satellite Navigation space assets. In this way, we are able to offer our customer an effective, efficient and accurate solution providing extended information on the status and performance of their facilities.
On one hand, the use of Satellite Earth Observation allows us to carry out an adequate flight planning and, thanks to the very high resolution (VHR) images, it permits us to analyse the status of the plant to verify that it is ready to be inspected (for example, detecting and monitoring the presence of obstacles, vegetation in excess, status of installation cleanliness, etc.).
On the other hand, the use of Satellite Navigation allows us to execute precise flights with our drones and, accurately locate the detected faults at solar module level, integrating the navigation solution in our algorithms.
The Baseline Design Review (BDR) has been completed in January 2021.
Due to the restrictions caused by the COVID-19, the workshops that were planned could not be carried out. Instead, several meetings have been held with various stakeholders in which the photovoltaic market, the solutions currently available for inspections and the customer main needs have been discussed.
Currently the algorithmic design phase is being closed and the results obtained in the trade-offs carried out to date are very encouraging. In addition, the design of the user interface that will be used to exploit the data obtained after processing the inspection data has also been consolidated.