This week, Tri-State line maintenance personnel were engaged in both classroom and hands-on live-line training exercises at the Brush, Colo., field facility and on nearby energized transmission lines to put into practice what they have learned.
As always, the exercise focused on safety with a detailed “tailgate” briefing on site provided by Clint White, transmission field training specialist based in Ogallala, Neb., and Jim McDonald, a contractor to Tri-State specializing in live-line training. This yearly exercise was also held last week in New Mexico for the association’s maintenance south crews and is scheduled to be held next week near Salida, Colo. for maintenance west personnel.
The tailgate meeting spells out the specific task to be accomplished by each crew member and points outs safety hazards such as fall protection and maintaining clearances from live lines and energized equipment. In addition to the crew that scales the tower and assembles the equipment needed to perform the maintenance activity, another crew is needed on the ground to direct the procedure and shuttle equipment via hand lines up to the crew members above. Another team is needed to stand by on a man lift in position aloft to assist and perform emergency rescue if required.
There are essentially two types of live-line procedures in the electric utility industry. The bare hand technique is one in which the lineman makes direct contact with the power line so that his body is energized to the same potential of the line – much like a bird on a wire. This requires special equipment, including a conductive suit that must be worn by line personnel who are making contact with energized equipment.
The second live-line technique is called “hot sticking,” which involves the use of specialized insulated tools that keep the crews safe from making contact with live components. Both of these techniques were practiced at the Brush training exercise.
Although for Tri-State crews live-line work is more the exception than the rule, it is sometimes necessary during periods of high load or when taking a line out of service for repair may present reliability issues to the rest of the system or interrupt service to Tri-State’s members.
In this instance the exercise involved removing and replacing one of the insulator strings on the transmission tower. The tower crew worked with precision high above their ground crew assembling a crane and cradling system that allowed them to remove the insulator string and simulate replacing the 250-pound string with a new one without the slightest interruption of service on the line.
“I thought the exercise went well today,” said White. “We did have a few issues with wind hampering ground communications, but our apprentices and our journeymen worked well together and got the job done and undoubtedly learned something along the way.”