Many transmission lines have had hardware failures because of wind-induced vibrations. Over extended periods of time, wind-driven rubbing between the line insulator hardware and associated crossarm-attachment points can cause total failure of the crossarm at the point of attachment. These vibrations also can cause wear between the metal components on the transmission line hardware. Sometimes this component wear can result in line failure or multiple arm replacements, which can be expensive.
Over time, in many cases, the clevis pin can completely erode through the attachment of the arm. If the hole is not repaired after it becomes worn, it may deteriorate to the point of no longer being able to support the weight of a conductor. In these situations, conventional methods may require replacing the entire arm.
Georgia Power was challenged to find a solution that would eliminate the component wear from wind-driven sawing motions. In the past, some of its transmission crews used stabilized binoculars and other specialized equipment to inspect the hardware and focus in on the attachment points. This task was complex, time-consuming, expensive and labor intensive. In addition, it diverted crews away from other work when the arm attachments needed to be replaced because of these types of failures. The utility wanted a more efficient, cost-effective way to solve this problem.
Developing the Solution
A maintenance and reliability staff specialist took on the challenge of developing a solution. During his career with Georgia Power, he had designed solutions for other problems, so once again, he jumped right in. Within a matter of weeks, and several prototypes later, he built a prototype — a stainless-steel bushing — that was stronger than his other designs. He developed a cost-effective repair process that was easy, simple and fast while also solving a long-standing problem Georgia Power faced with transmission line hardware failures.
Installing the Device
Linemen insert the stainless-steel bushing into the attachment hole in the arm. Because the attachment is made of a corrosion-resistant stainless steel, the workers no longer need to replace the entire arm. As a result, the reliability has improved, and the hardware life has been extended. The utility also has saved a significant amount of money in transmission and distribution line repairs. Georgia Power plans to install the bushings on new construction to prevent wear and eliminate failure from wind-induced vibrations.
The stainless-steel bushing not only can be used for electric power transmission and distribution systems, but also anywhere a hole or aperture needs to be repaired or reinforced. The new bushing was tested and solved the wear problem while also increasing the strength of the clevis attachment significantly.
The attachment bushing also provides several key business benefits such as safety, overall cost reduction, improved operational efficiency, enhanced reliability and risk mitigation.
Georgia Power’s field workforce has installed several these bushings on 230-kV lines throughout its service territory. As a result, the utility has been able to prevent arm replacements as a result of failures from wind-induced vibrations on hundreds of worn crossarms. Minimal training is required to learn how to install the bushings, and the savings on this one project alone were calculated and shown to be significant in labor, equipment and materials.
Because of the benefits of this innovative solution, Georgia Power was granted a patent from the U.S. Patent and Trademark Office, and in honor of its inventor, Georgia Power employees have informally nicknamed the product the Buddy Bushing. The trademarked product also is being sold and distributed by Diversified Product, which has worked with linemen to bring their inventions to market for the past 15 years.
Buddy Phillips, the inventor of the Buddy Bushing, is a line specialist for Georgia Power in the maintenance and reliability department. He has been with the utility for 42 years and is responsible for line maintenance, including inspection of new line construction, steel structure repairs, evaluation of hardware failures and helicopter inspections. He also is responsible for transmission lines in Georgia and live-line training.
Diversified Product | www.diversifiedproduct.com
Georgia Power | www.georgiapower.com