Many transmission lines have had hardware failures due to wind-induced vibrations. Over extended periods of time, the wind-driven rubbing between line insulator hardware and the associated cross arm attachment points can cause total failure of the cross arm at the point of attachment. These vibrations cause wear between the metal components on the transmission line hardware. In some cases, this could result in line failure or multiple arm replacements, which can be very expensive.
In many cases, over time, 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 that it may no longer be able to support the weight of a conductor. In these situations, conventional methods may require replacing the entire arm.
In the past, some transmission crews used a helicopter with stabilizers and other specialized equipment to inspect the hardware, and to focus in on the attachment points. This task was complex, time consuming, expensive and labor intensive and diverted crews from doing other work when the arm attachments needed to be replaced due to these types of failures.
To solve this problem; Georgia Power was challenged to find a solution to eliminate the wear due to wind-driven sawing action. With this concept in mind, Buddy Phillips, a maintenance and reliability staff specialist took the challenge given, and went straight to work. Over his career with Georgia Power, Phillips had recognized other business solutions and within a matter of weeks, and several prototypes later, he built a prototype that was stronger than then his other designs. What Phillips developed was a cost-effective repair process that was easy, simple and fast and a solution for a longstanding problem Georgia Power was having with their transmission line hardware failures.
Installing the device
Linemen use this device by inserting 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, it improves reliability and extends hardware life and has also saved a significant amount of money in transmission and distribution line repairs, and because of its success, Georgia Power plans on installing the bushings to prevent the wear on new construction and to eliminate the failure due to wind induced vibrations.
The stainless steel bushing can not only be used for electric power transmission and distribution systems, but can also be used anywhere a hole or aperture needs to be repaired or reinforced. The new bushing was tested, and not only solved the wear problem, but also increased the strength of the clevis attachment significantly.
Providing key benefits
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 a number of these bushings on 230kv lines throughout its service territory to prevent arm replacements due to failures from wind induced vibrations on hundreds of worn cross arms. There is minimal training required and the savings on this one project alone were calculated and shown to be significant in labor, equipment and materials.
Due to the successful benefits of this innovative solution, Georgia Power was granted a patent from the United States Patent and Trademark Office, and in honor of its inventor, Georgia Power employees have informally nicknamed the product “The Buddy Bushing”. The trademarked product is also 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 is a line specialist for Georgia Power, in the Maintenance & Reliability Department, has been with the company for 42 years, and is responsible for line maintenance including: inspection of new line construction, steel structure repairs, evaluation of hardware failures, helicopter inspections. He is also responsible for Transmission lines in Georgia and live line training.
Diversified Product, www.diversifiedproducts.com
Georgia Power, www.georgiapower.com