With the hot-commissioning deadline fast approaching, an EPC in charge of constructing one of the largest solar farms in the state of Alabama, faced a major hurdle. The owner wanted a thermal study of the asset as part of the punch list activity prior to commissioning. The EPC needed a quick and easy solution to both identify major PV and electrical defects and remediate thermal issues. Delays, if any, would prove very costly considering the cliff dates and liquidated damages built into the EPC contract.
Since the EPC had used SenseHawk’s software for several activities during construction at the site (including earth moving and construction monitoring), it considered using SenseHawk’s aerial thermography solution to tackle the problem. The Digital Twin of the asset, along with all the components and inverter-combiner box-string labels, had already been on-boarded to the platform.
Aerial thermography studies done by O&M teams, post-commissioning (6-12 months into the life of the asset), were quite common even 5 years ago. However, pre-commissioning studies are just starting to become de-rigueur. Owners are realizing the benefit of catching thermal and electrical failures early, right after construction is completed. More importantly, OEMs are recognizing the validity of these studies in processing warranty claims, subject, of course, to rigorous on-field analysis. After all, aerial thermography reports can only reveal a symptom. The root cause (which ultimately determines the validity of a warranty claim) needs to be ascertained on the field through visual inspection for damage or IV curve tracing on defective modules. Most providers that perform aerial thermography deliver simple PDF or CSV reports of thermal defects. The translation of these reports into the action required on the field is a laborious process involving printouts, guesswork regarding the defect location, and a lot of heartburn.
Figure 1: The digital twin of the solar power plant was present on the SenseHawk platform from the start of construction
The EPC had also completed an important activity that would prove to be very useful for warranty claims. During the final stages of construction, serial numbers of every installed module had been captured and saved onto the Digital Twin using the SenseHawk scan app for inventory mapping.
Figure 2: Module serial numbers had been captured for all installed PV modules using the SenseHawk Scan App
The EPC had three weeks to identify, classify and remediate PV and electrical defects, on a 130MW site. The first two steps (identify and classify) were completed in one week. SenseHawk’s pilots completed drone data collection and uploaded images to the thermography platform within four days. The thermography reports were available on the platform three days later and indicated over 5000 defects of various types, spread out over 900 acres. The EPC still had two weeks to fix these issues and close out the punch list.
Figure 3: The SenseHawk thermography application identified and classified over 3500 defects on the powerplant’s map view
Since SenseHawk’s thermography application is tightly integrated with its suite of productivity tools designed for management of tasks and workflows on the field, the task feature could be leveraged to drastically reduce the time taken by the EPC for defect remediation. Each defect resulted in the creation of a related task that could then be assigned to field teams, with detailed checklists for remediation, options to add attachments to help guide field personnel, and more.
Figure 4: Each defect resulted in the creation of a task that could be assigned to members of the field team
Figure 5: Each defect related task could have detailed checklists for remediation, attachments to help guide field personnel, and more.
Each task contained the defect type, string number, and temperature delta of the hotspot. The Project Manager was able to attach custom checklists to the tasks, one for each defect type. Defects were classified based on severity; string related issues were tackled first, followed by module related and finally by cell related issues. Multiple field teams were created; defects were assigned to each of them to enable quick investigation on field. These tasks would then show up on the SenseHawk mobile application allowing users to easily navigate to the exact locations of defects using their mobile GPS.
Figure 6: Field users could navigate to the exact defect location using the mobile application
Technicians spread out to individual defects and carried out investigations based on the task list. A large number of defects were found to be caused by cracked modules – something that seemed to be caused by a bad batch from the PV supplier. Photographs of these damaged modules were attached to the associated task on the app.
Figure 7: Field investigation for this defect revealed broken glass on the module – a manufacturing defect. Photographs of the damaged modules were attached to the associated task.
Another large set of modules had abnormally hot cells, most likely caused by a manufacturing defect. These defects were verified on the field through IV curve tracing, and screenshots of the IV trace were added to the task associated with the defect. The EPC was able to then export the results of the on-field defect investigation into excel sheets, complete with hyperlinks to the tasks’ attachments.
Figure 8: Results of the field investigation were summarized in excel for easy reporting to the Owner and to the OEM for warranty claims
The excel clearly indicated the resolution status of each defect – some of them were resolved on the field, while many (over 3500) were liable for warranty claims. The photos and other attachments made to each defect related task provided a quick and easy way to verify this. The EPC submitted the excel file to the owner, who was satisfied that the defects were either already rectified or would be rectified through warranty claims and cleared this item from the EPC’s punch list. This was done within 10 days of the thermal reports being made available to the EPC, well within the commissioning deadline.
Post-commissioning, the actual task of warranty claims remained. The serial numbers that had been meticulously cataloged prior to the thermal scan, proved to be very useful. Each defect had the corresponding module serial number associated with it. The owner was able to simply send a list of defective serial numbers to the OEM, who was able to quickly verify the claims using evidence already gathered during the on-field investigation.
Figure 9: Module serial numbers were available for each tracker row, making the warranty claims process seamless with the supplier
In this manner, a seemingly gargantuan task was completed in less than three weeks. The powerplant was operating at maximum efficiency from day one, and the usually complicated task of warranty claims was reduced to a simple checklist activity.
SenseHawk’s unique technology stack incorporates elements of drone mapping, machine learning, and lightweight mobile applications that can transform the way you run your solar plant. To know more, contact us today.