The evolution of thermal imaging traces a path similar to most other technology. Over the past 20 years, thermal imagers have been transformed from heavy, fragile, expensive and complicated instruments to compact, affordable, rugged, portable, easy-to-use tools. That transformation has much to do with why infrared cameras are being found in more walks of life.
Thermal imagers offer a wider range of sensitivities, resolutions and lenses that allow users to get precise thermal detail from targets as close as a few inches or up to a few hundred feet away—making them especially useful to utility workers who inspect all kinds of high voltage transmission system assets.
As utilities face the challenge of keeping the components of an aging and degrading power grid up and running, they are finding utility in infrared cameras. Normal wear and tear, and damage from extreme weather are difficult to keep up with. Preventive maintenance can help prevent costly and dangerous failures, but many utilities are running with leaner crews who have to focus on immediate repairs first. That leaves less time for preventive maintenance.
Still, regular inspections of all aspects of the power network are critical to addressing potential problems before they become actual problems. These inspections are also required to enable utilities to meet increasingly rigorous safety standards. The affordability, portability and functionality of infrared cameras make them a practical choice for all kinds of utility inspections.
Most infrared cameras capture radiometric thermal images that contain apparent temperature measurements for each pixel within the image. A technician can identify an anomaly in the image and then drill down into the hottest areas to calculate the apparent temperatures. Because infrared cameras can scan a component from a safe distance while it’s running, they are indispensable for technicians working around substation switch gear or high voltage transmission lines.
Utility companies must regularly inspect transmission assets to find hot spots before they cause unplanned and often expensive outages. Loose contacts, corrosion or internal defects in fittings and weakened or failing cable splices can cause hot spots that pose a serious threat to the integrity of a power transmission system. It takes only a high gust of wind against a power line with a weakened splice to bring down the line.
Because infrared cameras are now lighter, less expensive and easier to use, they are available to more utility workers. In addition to being used for surveying miles of power lines through remote and difficult terrain from a helicopter or inspecting tower connection fittings or contacts from a bucket, high resolution infrared cameras also allow better inspections from the ground. They also provide easy ways to identify the physical location of a temperature anomaly; depending on the model they’re using, technicians can add a text or voice annotations to the image as they record it. They can also capture a visible light image simultaneously with the infrared image to make it easier to see visual location details.
Keeping a Safe Distance
Substations and switchyards have many moving parts that handle high voltage. Any of those parts can degrade and overheat and cause a power outage or worse. The revenue and liability consequences of such an event makes regular inspections a necessity.
Technicians can use an infrared camera to scan the outside of a substation from up to 100 feet away. They can inspect the transmission line that feeds the station, the circuit from the transmission line, high side insulators (arrestors) and bushings on the transformer, and the regulators, all from the ground.
In power plant switchyards, infrared cameras are useful for checking the oil level, flow restrictions and leaks in oil filled breakers and transformers. They also can identify hot spots in circulating pumps, generators, insulator bushings, and connectors and control cabinet components.
Getting an Eagle Eye View
An equipment failure in a transformer vault can be costly and dangerous. Climbing down into a cramped underground vault, however, isn’t pleasant. Using an infrared camera can make it easier. Some infrared cameras connect wirelessly to mobile devices to transmit scan results. A technician can lower a wireless infrared camera equipped with a wide angle lens into the vault to quickly scan a large part of the interior from above. The technician can view the results above ground on a mobile device or a notebook PC. If there are additional areas that can’t be seen, the technician can don personal protective equipment and climb down the ladder and complete the inspection. This allows inspectors to identify obvious hazards from a safer distance before moving into a hazardous area.
Catching the Sun
Inspecting photovoltaic (PV) power stations (also called solar farms) typically involves thousands of PV panels. That is a large area to cover, which makes it an ideal application for a high resolution infrared camera. Technicians can quickly scan a broad expanse of panels—top and bottom—to find hotspots caused by defects or degradation, and to inspect the inverters and transformers connected to the solar arrays. After problem components are repaired or replaced, technicians can re-scan to ensure restoration of optimal generating capacity.
As utility companies continue to be challenged to do more with less, infrared cameras play a large role in increasing productivity and safety so workers can get the job done efficiently and go home at the end of the day.