How to get a true picture of faulty solar panels
Flir Tau core helps identify anomalies in solar plants.
It is a compact, lightweight thermal imaging core that can be mounted under unmanned aerial vehicles (UAVs), also known as drones. The unit can be used to inspect photovoltaic (PV) cells in solar plants at hard-to-get-to locations.
“If you look at imaging performance, size, weight and energy consumption Tau is the perfect tool to mount underneath a UAV,” says Antonio D’Argenio’s of Italian firm Panoptes.
He started to work with small drones at the end of 2009 to collect aerial geo-data using consumer cameras. But after a short time felt the need for cameras and thermal detectors that are especially designed for small drones.
“Therefore, we designed Panoptes, a family of multi-sensor modules featuring Tau and coupled with software to be used with small UAVs,” he says.
The first multi-sensor that was designed is the mini-Thermo (mT), a small and compact multi-sensor platform. It is equipped with a thermal imaging camera and a CCTV camera.
The mT-Panoptes is designed to be mounted underneath UAVs that are inspecting photovoltaic cells in solar plants.
“In a solar plant, anomalies in photovoltaic cells and modules can cause a reduced efficiency of the entire system,” says Antonio. “Periodic preventive maintenance inspections are aimed at locating malfunctions.
“A fast and easy way to find anomalies in photovoltaic cells is using a thermal camera that creates a crisp image based on subtle temperature differences, and makes temperature differences visible. These temperature differences between components can be an indication that there are malfunctions.”
During f lights, both thermal and HD video are recorded by a two-channel mini DVR. Data is also transmitted in real time to the ground.
The thermal camera is used to find anomalies in solar panels and the visible camera can be used as a reference against the thermal image – so operators understand if thermal anomalies are related to faults in modules or from external factors such as shadows.
The mT Panoptes multi-sensor can be used on UAVs with low load capacity (<250 g). It integrates a Flir Tau thermal imaging core that produces images of 640 x 512 pixels on which the smallest of details can be seen. At the same time it is equipped with a 720p video camera.
“Our Solar Inspector software offers an intuitive environment for both operation in the field and for further analysis afterwards,” says Antonio. “The mTPanoptes can be bundled with a tablet PC running Windows 8 Pro software.
“We have chosen Flir Tau because it is the perfect core to be integrated into the mT-Panoptes,” says Antonio. “No thermal imaging core is so compact and lightweight. It also delivers excellent quality thermal images.
“Tau also has an extremely low power consumption, which is important since the mT-Panoptes needs to operate on batteries.”
The Tau thermal imaging core detects temperature differences of 50mK. Its size (44.5 x 44.5 x 30.0 mm), low weight (72 grams) and low power consumption (900 mW ) make it the ideal core for mounting under a UAV for any application.
A drone fitted with (insert) a Panoptes lightweight camera fitted with a Tau thermal imaging corefrom Flir. It is used to detect ‘dead’ areas in hard to reach solar panels. Photos / supplied
The white areas shown above in the red circle are what dead cells look like using the Tau sensor. Shown right is what looks like a faulty solar panel, but is in fact a cooler area created by a shadow cast by a nearby object.