How Smart Infrared Cameras Empower Power Companies
As business cycles quicken, it's getting more important for power companies and service providers to see catastrophic events in the making and to take appropriate remedial action.
As business cycles quicken, it's getting more important for power companies and service providers to see catastrophic events in the making and to take appropriate remedial action. Unfortunately, many problems in the making can’t be diagnosed by sight alone. They require a combination of insight and the right tools to make up for the blindness lurking beyond our senses.
For power companies--their transmission and distribution groups as well as their generation and substation groups--thermal imaging cameras are indispensable tools for spotting problems before they are out of control. For outdoor thermography work, for example, where small connections are examined from a distance, technicians use thermal imagers in substations, looking for, in some cases, small hot spots--small connections that are starting to heat up, potentially causing outages and expense.
One utility found a hot bushing on an ISO-phase transformer at a nuclear power generating plant. This was one of three transformers on the output of a turbine generator. Making a repair would require shutting down the plant. But not discovering this problem until it was too late could have been much more costly, not only in repairs, but in lives. For this plant, accessing such information justifies the cost of a thermographer imaging the plant every morning and sending the analysis to the engineering and maintenance team as well as to the plant manager--and even to the CEO of that utility. This has enabled the plant to run as long as six months without an unscheduled outage.
A Layered Approach
Even in facilities where infrared (IR) cameras have been used, poor ongoing education about the proper use of this equipment is problematic. That's why large companies such as Ford and General Motors employ their own expert thermographers who travel from plant to plant on a regular basis, inspecting electrical distribution equipment, spot welding lines and conveyors carrying assemblies from station to station. Smaller plants may rely on their maintenance people to do the same thing, equipping them with lower-cost cameras to do quick troubleshooting, then relying on expert thermographers from the outside to verify any trouble spots found or to come in annually to do a clean sweep inspection of the facility. That's called a layered approach to thermography.
Technology's value is only as high as the level of training invested in its users. That knowledge will help them avoid making mistakes or having to fix problems that don't exist.
What Can Go Wrong?
Consider, for example, the case of the rookie thermographer who reported a hot area on a $5,000 circuit breaker. On its discovery, the plant disconnected that section of the electrical system and replaced the circuit breaker. After re-firing the system and then taking a second look at the "faulty" circuit breaker, technicians couldn’t find anything wrong with it. Meanwhile, back at the plant, that same thermographer found the same hot spot in the new circuit breaker. What he was reading was his own thermal reflection in the screws--his body heat.
Proper training would have taught him about reflectivity and emissivity, and how to differentiate true hot spot problems from heat reflections. He would have learned to move his camera around to see if the hot spot changes or travels along a piece of reflective material or whether it always maintains itself in the same location.
Other problems arise when equipment is misapplied--for example, trying to analyze, or compare, areas that are too small to measure with a particular IR camera. All optical systems have limitations. An operator often tries shooting at a target 30 feet or 40 feet away but the camera cannot properly resolve the object. The operator will miss problems because he or she doesn't know there is an optical resolution limit depending on the equipment's lens, detector or the design of the camera. A telephoto lens or a higher resolution camera may be needed to properly analyze this particular object.
While this is a problem of education, it's also a problem with those doing the educating--the vendor selling the system. They should be advising customers on choosing the appropriate technology for their environment. This failure to educate is happening more as equipment is made available online. Many buyers look at an IR camera with the same naked eye that misdiagnoses problems in their work environment--and the result is equally problematic.
Get the Best of Infrared Technology
Training notwithstanding, the raw technology of thermal imaging is improving with each generation of product, offering educated users a broad selection of thermographic solutions. Although 640 pixels x 480 pixels is state of the art, that will soon double and quadruple for unprecedented image quality, enabling users to see smaller targets or get more target detail.
With current capabilities, a technician can:
- Store those images along with additional data such as the electrical load on the system at that point in time;
- Identify a particularly problematic piece of equipment;
- Document recommendations for repair and follow-up (those notes can take the form of text or voice comments stored on the image);
- Download an image onto a mobile phone or tablet and input data there; and
- Archive information for later data trending over time and situational analysis.
In addition, being able to go from a general "I see a hotspot" to specifying what part of a component is heating up can determine which parts need to be ordered for a repair and minimize the chances of selecting the wrong ones--and then having to re-order or shut down.
For those cases where long distances must be covered, the newest equipment can do the work that previously required heavy telephoto lenses. Thermographers looking at overhead bus duct runs as far as 30 feet to 40 feet away, for example, won't have to carry around a 2X telephoto lens to see small defects. Instead of looking for large temperature differentials, some of the newest equipment enables users to see the smallest ones. A difference of 5 F to 7 F can foretell a critical fault. While the cost of a telephoto lens can range between $1,325 and $11,500, having such capability built into the next generation of cameras will pay for them.
The ability to read heat signatures at long distances has enabled utilities to use crews in vans or helicopters equipped with IR cameras mounted outside them to monitor outdoor substations and the equipment associated with them, including transformers, circuit breakers, disconnects and lightning arresters. Problems can be diagnosed faster and safer than making linemen climb poles into 250,000 volts, testing by touching.
In the future, drone platforms may enable taking technicians out of this process and adding the ability to perform roof and building scans, as well. Whether this happens is up to the Federal Aviation Administration, which is still studying commercial drone safety and viability.
Recipe for Return on Investment
The following suggestions can help speed thermography's return on investment:
- Develop a regimented inspection plan so all critical system connections are checked on a regular basis. For such a plan to be effective, the IR equipment must be sized to the job—the connections being analyzed, the distances being covered, and the temperature ranges being measured.
- Arm personnel with the correct equipment and training. Then, as the safety net expands and the ability to upgrade evolves, changes can be made that fit the situations.
Whether a plant decides to invest in thermography or in professional thermographers, the return on that investment depends on its smart application. Users should be certified at one of three levels:
- Level I is an entry-level thermographer, who can do basic analysis and troubleshooting, and save images;
- Level II thermographers have more diagnostic capabilities and can oversee surveys and put together full reports; and
- Level III thermographers can write procedures and specifications, and determine temperature limits for different pieces of equipment; this person could oversee an IR program at a plant or a company-wide level, providing advanced image analysis and consulting. This person can be an engineer who can design solutions.
Wherever your needs fit in this spectrum, an investment in thermography education will pay back in better use of IR technology as well as in the equipment and systems it safeguards.
About the author: Gary L. Orlove, P.E., is the Global Curriculum Manager at the Infrared Training Center and Chairman of the InfraMation Thermography Conference. He holds degrees in Energy Engineering and Zoology from the University of Wisconsin and has been using IR thermography since 1975. He is also an application engineer for FLIR Systems Inc., manufacturer of imaging systems including infrared cameras, aerial broadcast cameras and machine vision systems. He can be reached at email@example.com