When looking for a place to land, birds often settle on power lines and poles. As a result, they can come in contact with power lines, leading to accidental contact. To prevent bird mortalities and related power outages, Carbon Power & Light's linemen are in the process of swapping out wood poles for steel structures on its distribution system.
The Wyoming utility incorporated best practices for avian protection planning, construction techniques and associated materials during the steel pole installation. The cooperative worked with EDM of Fort Collins, Colorado, to revise its avian protection plans for the transition from wood to steel poles from Valmont Industries. The company also changed its construction practices with respect to circuit phase-to-phase and phase-to-ground separations to isolate potential avian contact incidents.
As with wood pole construction, the plan used the coverage of circuits with appropriate materials to insulate and mitigate potential avian contact incidents. The switch to fiberglass materials assisted in insulation as well.
Carbon Power & Light also implemented the suspension of conductors below the crossarm, which provides a perch area. These and other best practices are identified by the Avian Power Line Interactive Committee in its Avian Protection Plans Guidelines.
Shift to Steel
The integration of steel distribution poles into the utility's distribution system in the 1990s has helped to protect birds, but it also has had other positive changes as well. The cooperative now has more than 4,600 steel distribution poles in its system, which equates to 14.5% of the company's distribution system. This percentage continues to rise as steel is now used for all new poles and replacement poles at the cooperative.
The overwhelming majority of new and replacement distribution poles set — from small routine pole changes to larger multipole line work — are steel. The utility, which installs an average of 300 to 400 steel poles annually, typically uses Class 3 or Class 4 poles ranging in height from 30 ft to 70 ft. Carbon Power & Light installs less than 10 wood poles annually.
The company decided to switch to steel poles and fiberglass crossarms back in the early 1990s when the price of wood poles started to skyrocket. At that time, the company decided to look at steel for several reasons — primarily, because steel poles are expected to last up to 80 years. Additionally, the poles require minimal maintenance. And finally, the cost of wood to steel was comparable at that time. Steel poles may cost more but the benefits outweigh the initial cost difference. Steel helps the utility to create a more reliable system. So overall, the life-cycle cost is better with steel.
Making the Change
The acceptance of steel poles by the company's linemen was a nonissue. At first, the linemen were a little skeptical of the changes, but now they wouldn't want to change back to using anything else.
Little training was required during the transition. The linemen follow the exact same safety procedures and use the same type of insulated cover-up materials for both wood and steel poles when working with an energized line.
Carbon Power & Light orders its poles from the manufacturer as 95% drilled. The utility line crew drills the remaining 5% of holes in the field using a Unibit or a step drill bit.
One difference when working with steel poles, however, is that linemen need to insert climbing steps in the predrilled holes before climbing. However, the field crews usually use bucket trucks when working with steel poles. The utility keeps about 300 to 400 steel poles on hand for new installations and pole replacements. Linemen can use steel for a single pole tap or to build a complete three-phase line with hundreds of poles. In the Carbon Power & Light system, the average number of poles per mile of line is 18 for both wood and steel.
Reaping the Benefits
In the years that they have worked with steel poles, the linemen have realized several advantages beyond their life-cycle and cost benefits. For example, the poles are able to be resistant to nature's wrath. Standing tall during ice storms was one of the first benefits realized with the steel pole installations.
Some of the territory the utility covers is prone to ice, and every year, it would lose a few wood poles. Even though the company has had power lines go down with the weight of the ice, it hasn't had to replace broken steel poles in the middle of a storm. This has proved to be a major benefit.
In addition, with wood poles, the company had problems with winds knocking them down, with lightning shattering the pole tops, and with either lightning or a broken-down insulator starting fires on the pole tops. Steel is a solution to preventing these pole-top fires.
The steel poles also are a deterrent to woodpeckers, which have created problems for wood poles in the area. By replacing the wood with steel poles, however, the company is ensuring its system's longevity and service.
Another benefit of the steel poles is that less maintenance is required. A steel pole's resistance to shrinkage is a major benefit in the field. With a wood pole, shrinkage often occurs after the pole is set, which requires ongoing maintenance to adjust and tighten the hardware. With steel, the utility doesn't have shrinkage, bending, bowing or twisting, and the hardware remains tight. When the linemen patrol their lines, they find no loose hardware on the steel poles. As a result, steel poles provide more reliability than wood poles and require less maintenance.
Aesthetics is another a key benefit. The utility's steel poles are uniform in size and straight with no splinters. And after the steel poles have been installed for awhile, the galvanizing dulls a bit and the poles blend easily into the environment. The utility's customers notice this and appreciate it.
The utility's service territory has everything from prairie to mountains, sand to rock, and it has put steel poles in just about every type of soil.
Steel poles have been the right choice for the utility for both operational and life-cycle reasons. The use of steel has helped crews harden Carbon Power & Light's line against storm damage, increased line reliability and given the community a more environmentally responsible alternative to wood. Making the switch was the right decision, and the utility hasn't looked back.
David Cutbirth (dcutbirth[email protected]) has worked at Saratoga, Wyoming-based Carbon Power & Light for more than 31 years. As a seasoned utility line professional, he has worked as a lineman and now serves as the director of operations. Carbon Power & Light provides power to about 6,100 customers in several small towns on the Wyoming/Colorado border as well as the outlying areas around Laramie. At the cooperative, Cutbirth's number-one priority is system safety.
Editor's note: The Carbon Power & Light crew was featured on Discovery Channel's “Dirty Jobs” program in January 2011 as part of a series on maintaining America's infrastructure. In the episode, the linemen are changing out a wood distribution pole with a steel one. A short clip from the program, which is titled “Working the Pole,” is available at http://dsc.discovery.com/videos/dirty-jobs-hair-fairy. Choose the “Working the Pole” option on the list underneath the video screen. For more information about steel poles, visit lineman.steel.org.
How to Create Your Own Avian Protection Plan
The Avian Power Line Interactive Committee and the U.S. Fish and Wildlife Service worked together to create a set of avian protection plan guidelines in 2005. Here are 10 principles of that plan, which utilities can use to customize their own programs for minimizing contact between birds and power lines.
Write a corporate policy. Create a statement on how your company will protect migratory birds through measures such as obtaining and complying with necessary permits, monitoring incidents of avian mortality, and constructing and altering infrastructure to protect avian species.
Train your employees. Set up a training session for your managers, supervisors, line crews, engineering, dispatch and design personnel. In this seminar, you should educate your employees on how to report an avian mortality, follow nest management protocols, dispose of carcasses and comply with applicable regulations, including the consequences of noncompliance.
Describe how to comply with permits. Discuss the process on how to obtain and comply with permits relating to nest relocation, temporary possession, depreciation, salvage/disposal and scientific collection.
Set construction design standards. Consider avian interactions in the design and installation of new facilities and the operation and maintenance of existing facilities.
Create procedures for nest management on utility structures. Be sure to explain these procedures to your employees during the training sessions.
Develop an internal reporting system. Utilities can voluntarily monitor avian interactions, collect data and then identify areas of concern such as problematic poles or line configurations. Companies can request Bird Mortality Tracking System software for free at http://aplic.org.
Conduct a risk assessment study. Evaluate the risks posed to migratory birds by collecting and reviewing data on high avian use, avian mortality, nesting problems, prey populations and perch availability.
Take mortality reduction measures. Once you assess the risks, then develop a risk reduction plan as well as a schedule for implementation.
Enhance avian populations. Utilities should not only try to reduce avian mortality, but they also should focus on developing nest platforms, managing habits to benefit migratory birds or working with organizations to develop new ideas for protecting migratory birds.
Have quality-control measures in place. Review existing practices and conduct an independent assessment of your avian reporting system.
Create public awareness. Educate the community about the issues with avian electrocution as well as your company's avian protection program.
Identify key resources. Compile a list of experts to help resolve avian issues such as consultants, resource agencies, universities or conservation groups.
For more information, please visit www.aplic.org/uploads/files/2634/APPguidelines_final-draft_Aprl2005.pdf.
Avian Power Line Interactive Committee | www.aplic.org
Carbon Power & Light Inc. | www.carbonpower.com
EDM International | www.edmlink.com
Valmont Industries | www.valmont-newmark.com