Public power utilities consistently maintain a high level of reliability and one of the ways they do that is to get out in front of potential equipment failures on their transmission and distribution systems before they lead to outages or other operational issues.
The use of infrared technology has proven to be a key tool for public power utilities as they look to nip potential reliability issues in the bud.
Some public power utilities are now turning to drones as one more tool in their reliability toolbox, using the drones as part of their surveying of distribution and transmission infrastructure.
In some cases, public power utilities are either moving forward with plans to equip drones with infrared cameras or planning for such a move down the road. Along with infrared cameras, other technologies are also getting a closer look by public power utilities including Light Detection and Ranging (LiDAR).
[This is the first in a two-part article. The second story will detail how the American Public Power Association’s Demonstration of Energy & Efficiency Development program has funded several projects related to the use of drones, along with infrared and other types of imaging technology, for inspections of utility infrastructure].
Columbia Water & Light
In the Midwest, Columbia Water & Light in Missouri has been using infrared inspections for long enough to see changes in the equipment that make thermographic inspection more feasible and economic.
Infrared cameras used to be huge and had to be cooled by liquid nitrogen but are now digital and about the size of a video camera.
The main purpose of Columbia Water & Light’s infrared inspections is to reduce the number of unscheduled shutdowns and to prevent damage by detecting equipment failure in its early stages. However, the technology can also enhance productivity and provide savings by identifying equipment that is performing poorly.
Every year, the utility uses infrared cameras to inspect 100% of its distribution system, “walking the streets and looking at power lines from the transformer to the power plant,” John Wulff, energy management specialist at Columbia Water & Light, said.
But Columbia Water & Light goes beyond just inspecting its own equipment. The utility offers free infrared inspections for key commercial and industrial customers on an annual basis as part of its utility service. “They can scan anything for them,” Wulff said.
Reliability is a key aspect of the service the utility provides, he said. Over the years, those infrared inspections have identified several problems that would have caused down time, from bad bushings on a transformer to bearings on a motor or from a bad breaker to a bad steam trap.
Columbia Water & Light also offers the inspection service to other public utilities in Missouri. The service is available for a fee to any member of the Missouri Public Utility Alliance, of which Columbia Water & Light is a member. Columbia Water & Light receives 50% of what MPUA charges its members.
A lot of smaller utilities that cannot afford the investment in infrared technology take advantage of the program, Wulff said. A camera costs about $36,000, but resources also have to be devoted to training camera operators.
Becoming certified as a level one thermographer takes about 40 hours of training. Wulff is certified at level two, which is more intensive and delves into the science behind the equipment and makes it possible to write more detailed reports. He is preparing to train for level three certification, which would allow him to teach thermography.
Columbia Water & Light is also considering using drones in its infrared inspection program. The utility has some trained pilots and has bought a digital drone camera, but not an infrared camera. “We think we get better pictures from the ground,” Wulff said.
The utility’s infrared camera has a zoom function that enables it to get close up images. The only thing it cannot do is look at equipment from the top. Drones could be useful for that, particularly for identifying heat loss or cooling loss on roofs, Wulff said.
CPS Energy, the public power utility serving the city of San Antonio, Texas, has been using infrared technology for about 15 years and is in the process of incorporating that technology into the distribution line inspections it does with drones.
“We have the [IR] camera and are waiting for the drone to accommodate that payload,” Craig Fewox, engineering associate at CPS, said. “It is a heavier payload, so we are using a bigger drone.”
That drone will likely be equipped with both an infrared and a regular camera, explained Jose Leandro, a planning coordinator at CPS and a drone pilot. The utility’s existing drones do not support interchangeable payloads. “One of things we want to look at is to use IR and a regular camera and take pictures and see the difference between the two,” he said.
The infrared cameras that CPS is using now are hand held and take pictures from the ground. Mounting an IR camera on a drone would give the utility the ability to get a closer look at the equipment it is inspecting and make the operation safer. A drone can be flown closer to equipment, such as live power lines, without the risk of electric shock to which the operator of a handheld IR camera would be subject.
The drone program has already demonstrated the benefits of closer inspections and of the bird’s eye view that a drone can provide.
Traditional line inspections are done by workers in a truck who drive the line and leave the vehicle for a closer inspection, sometimes using binoculars or a truck equipped with a bucket on an extendable boom.
Fewox says drone inspections have already caught several potential problems that would have otherwise been missed, such as a bird nest inside of equipment, cracked insulators, blown lightening arrestors, and cross arms that were beginning to fail.
An inspector on the ground has a fixed vantage point. The only way to get an inspection comparable to that of a drone would be “bucket up to every pole,” Fewox said. “Using a drone is more efficient and safer.” Adding infrared capability to the drones will serve to make those inspections more thorough, he said.
Infrared cameras can monitor the heat of equipment to see if certain wires or connections are running hot, particularly switches, Fewox said. “It will help us prioritize what we feel requires quicker attention.”
Fewox said he has already seen before and after examples of inspections where a circuit showed up hot in an inspection and then calmed down after maintenance was performed. “We do all of this to improve overall reliability,” Fewox said. It provides “the opportunity to fix and prevent future outages.”
New Braunfels Utilities
Meanwhile, another Texas public power utility, New Braunfels Utilities (NBU), is preparing to present a new drone program to its board of trustees in early 2019. The purpose of the drone program will be to increase productivity and efficiency of the utility’s operations.
In an interview with the Association, Robin Britton, Director of Technology Systems and Systems Control at NBU, discussed how the drone program will play a role in NBU proactively working to prevent power outages before they occur.
“Nobody wants to be out of power, so we want to prevent that whenever possible, so we are looking at using the drone program to proactively detect situations where things could result in an outage,” Britton said.
NBU would like to detect issues through pole and line inspections such as rust, deterioration, or vegetation encroachment “before it results in a problem.” In addition, the utility wants to remediate issues tied to animals such as squirrels or bird nests.
The drones could also be utilized prior to inclement weather, “so we can target areas for known outages to occur,” Britton said. “One of the benefits is that we can get drones mobilized and deployed quickly,” and then transmit information, “which makes them very well positioned for monitoring those situations.”
Britton said that the drones will not be equipped with infrared cameras, at least initially, under the program. “Initially, we are going to be looking at imagery,” she noted. “But we are going to be moving into new sensors systematically, so that will ultimately include IR and thermal, possibly electromagnetic spectrum sensors and LIDAR.”
In July 2017, NBU announced that it would be utilizing drones to perform inspections on three-phase electric distribution lines.
Britton was asked to detail how those inspections informed NBU’s efforts to prepare for its new drone program.
“I think our drone inspections in 2017 gave our utility some insight into the potential of what we could accomplish with this technology,” she said.
“Our initial flight of roughly five miles of distribution lines and poles showed us that we could use the technology efficiently and maintain 100 percent data retention,” Britton said. “Being able to review that video footage instead of relying on field notes or someone’s memory was a big advantage.”
The effort in 2017 also created “an excitement about the technology and calmed some of the hesitancy that people had.”
The most important thing that resulted from the 2017 drone inspections is that it got people “thinking about potential applications of the data and what we could do next and where we could apply this technology.”
The new NBU drone program is expected to yield cost savings in several areas including vegetation maintenance.
Britton noted vegetation maintenance is typically contracted out in the power sector. Keeping up with information tied to vegetation maintenance requires having “folks in the field to monitor that work. You need some precise data on where the vegetation exists and what the length of that is and what the severity of that vegetation encroachment is,” she said.
“Once we have all this information we can adjust how we price our vegetation maintenance with our contractors. So instead of paying for maintenance on an entire stretch of line, pole-to-pole, we can shift towards paying for the actual, measured length of vegetation coverage,” Britton said.
“Currently, we’re paying for a full span because we do not have enough data to say does vegetation run the entire length of the span or half way through. There’s a large potential for savings there.”
Moreover, NBU can also engage in quality assurance and quality control on its contractors to make sure the utility is getting quality work.
A key element of the new NBU drone program will be public communication related to the effort. “We want to make sure that our customers know we’re going to be respectful of their privacy by flying on easements and right of ways,” Britton said.
“But we also want them to understand that this program is financially responsible,” she noted. “One of the ways to clearly communicate the cost savings to our customers is by examining the cost per structure.” This means that when NBU needs to inspect a pole, how much does it cost to send a crew out to complete the task and how long does the task take. Once the utility has that information “we can come up with a cost per structure, per hour.”
That analysis allows the utility to compare the cost of completing the same tasks with a drone. “We’re working on the final numbers for this analysis, but there is a significant savings in automating the inspection process and the cost per structure comparison illustrates the results of that cost savings and directly ties to keeping customer rates low,” Britton said.
The NBU official said that the utility is leaning towards leasing drones rather than buying them for the program.
“If we lease our drones, we’d have a lower monthly cost for the program. It means our costs will be predictable, easy to manage,” Britton noted.
If something were to happen to a drone, the leasing company would be available to help with repairs, so if we have a camera issue or a sensor issue that we can’t diagnose, we have them as a resource to help us work out those issues.”
The technology for drones “is constantly evolving and at the end of the lease period, we would be able to upgrade our technology,” allowing the utility to avoid technology stagnation, the NBU official said.
Moreover, if there is an emergency situation, having the leasing company available “would allow us the ability to quickly acquire additional or specialized equipment from the leasing company.”
Meanwhile, Britton noted that NBU will be looking at strategic partnerships to improve the program and “to be a good community partner and support others. We’re beginning discussions with other utilities and entities in the area to ensure that we learn from their experiences.” She added, “while we’re in the planning phase right now, we do intend to work cooperatively to provide benefit to NBU customers as well as others that are in our community.”
Britton said that “our next steps are to work on finalizing our process work flow and how we deal with our data retention and then make sure that we have some solid budgeting.”
If the program is approved by the NBU board of trustees and does go forward, “I would anticipate the program would begin probably in the fall of 2019.”
The NBU board of trustees is expected to consider the drone program in February or March 2019.
“We’re going to be doing an informational presentation first before we bring anything financial to the board,” Britton noted.
Keys Energy Services
Florida-based public power utility Keys Energy Services has utilized infrared camera inspections of its transmission lines for several years.
“Knowing that a component may fail gives us the opportunity to complete corrective maintenance to achieve the highest reliability possible,” said Lynne Tejeda, Keys’ General Manager and CEO.
The inspections are conducted by Brady Infrared, a contractor for Keys Energy Services.
In September, Keys Energy Services noted that Brady Infrared would be conducting infrared camera inspections of transmission lines. “During the study, a special infrared camera will be used to detect heat anomalies which are a red flag for possible future equipment failure,” the utility said in a news release, noting that its transmission and distribution department will prioritize repairs as they are identified.
In an interview with the American Public Power Association, Dan Sabino, director of engineering and control at Keys Energy Services, said that the utility has been utilizing infrared inspections for at least 12 years.
When it comes to transmission lines, infrared inspections involve looking for hot spots. “We’re looking for areas that show up hot that might indicate damage to a conductor somewhere or a loose connection, broken static wires – all those things show up in the infrared inspection,” Sabino noted.
Brady Infrared provides a report to the utility with its inspection findings “and then based on how hot a spot is, they’ll categorize the finding, so we use that in our priorities,” Sabino said.
He noted that an arrester, for example, “might not show up as a real hot spot, but even a slight heating increase in an arrester is indicative that it’s going to fail soon, so things like that, we’ll put priority to that.”
Brady Infrared conducts either land-based infrared inspections of transmission lines for Keys Energy Services or from a boat. Drones have not been utilized for the inspections.
Hartford Steam Boiler Inspection and Insurance Company, an insurer for Keys Energy Services, conducts an infrared inspection of all the utility’s substations.
Sabino said that for utilities that may be considering infrared inspections, “they need to find someone with experience to interpret the results. Things can look really bad in an infrared picture, and it’s not bad at all.” He noted that an infrared camera “picks up the hottest object. But it might not really be hot, it just is hot in comparison to everything around it.”
New York Power Authority
The New York Power Authority has been collaborating with the Electric Power Research Institute to investigate and evaluate automated inspection and image processing capabilities using drones.
The project will field test new technologies with the goal of making transmission system inspections safer, faster and more efficient while providing greater detail than current techniques.
NYPA technicians would be able to place a drone at the base of a transmission tower and start an inspection with a push of a button. The drone will follow a routine, gathering information on the structure and key components. Once a tower inspection is complete, the drone will return to its launch position and can then be placed at the base of the next tower to repeat the process.
To further automate the process, software is being investigated to analyze the thousands of images gathered during each inspection, NYPA said in October. Machine learning processes will be used to generate criteria for identifying potential issues, like broken or cracked insulators, ice buildup on a tower, or structural degradation. That will help reduce the amount of content that NYPA inspection teams need to review to determine the appropriate course of action.
The inspection and image processing automation project, which is part of NYPA’s Asset Management and Smart Generation and Transmission strategies, kicked off in early 2018. The final product will be a report, issued by EPRI, discussing the practical aspects of an automated inspection program and a roadmap for utilities to follow for implementation. The insights gained as part of the project will allow NYPA to better monitor and maintain the New York State transmission system as it works to become the nation’s first end‑to‑end digital utility, NYPA said.