Thermal imaging technology is now being used in surveillance applications at unmanned solar farms in South Africa after two 33 megawatt solar farms were initially set up in 2012 the Northern Cape.

To protect its valuable ground-mounted solar panel assets against unwanted intruders, Tenesol called upon security specialist TeleEye SA, which relies on thermal imaging technology for surveillance applications.

Solar power plants are usually unmanned sites and require real-time monitoring day and night in order to efficiently deter unwanted intruders and prevent vandalism.

TeleEye South Africa, a local division of Hong Kong-based company TeleEye, has many years of experience in securing public utilities sites which enables 24/7 standalone and remote operation with real-time monitoring and recording.

For the two solar plants, TeleEye, along with systems integration partner, Stallion Security provided Tenesol with a complete perimeter surveillance solution consisting of thermal cameras, video analytics and alarm management. The two solar plants have perimeters of 5km and 8km, and have been secured with thermal imaging cameras from FLIR Systems and electric fencing.

Philip Smerkovitz, Managing Director of TeleEye South Africa, explains that FLIR thermal cameras deliver very accurate optics and image quality along with robustness, which is an important factor in the harsh temperatures of the sites they monitor. The two solar farms are located in the Karoo desert where daytime temperatures of 40°C in summer are not uncommon.

FLIR thermal cameras allow monitoring day and night. Without any additional lighting, it is possible to detect intruders approaching the perimeter at night. The thermal camera’s ability to see in bright sunlight conditions was also important because sunlight can obviously be very bright in the Karoo desert. Glare from the sun may blind conventional video cameras, effectively hiding vehicles, people and animals.

In comparison to traditional video cameras, thermal imaging cameras can also cover a larger viewing distance, which means that fewer cameras are needed to efficiently monitor the perimeter. With thermal cameras, there’s no need to invest in or maintain expensive lighting infrastructure. For these two solar parks, 5 and 11 thermal imaging cameras were installed for the 5km and 8km perimeters respectively.

TeleEye was responsible for the entire specification of the surveillance project, including the definition of the camera technology, video analytics and alarm management. In order to calculate the correct camera viewing distances, TeleEye used FLIR Raven software, the free thermal security site planning tool, which allows the user to conveniently display both range and location for each camera specified. The software shows the area of detection coverage, allowing the user to plan the placement of the cameras.