Wood Pole Replacement Where the Winds Blow.
Published in: Transmission & Distribution World
Date: 2/1/2007
By: Mueting, Justin
In early January 2007, western Kansas received 3 inches of ice followed by almost 3 ft of snow. Our system in central Kansas was on the edge of this storm, but it was enough to remind us about the importance of maintaining a robust transmission and distribution system. Most of our crews were dispatched to Dodge City, Liberal and other smaller towns like Utica and Almena to assist in restoring power to Aquila customers.
A pole line located in the central plains of Kansas has to be strong. Higher-than-normal winds are common on the flatlands, so regardless of the frequency of ice and snowstorms, Aquila maintains its poles to meet or exceed the extreme wind load requirements. During a normal workweek, these conditions keep Aquila linemen based in Concordia, Kansas, busy. When they aren’t responding to trouble calls or replacing transformers or switches, there are always poles to be replaced and crossarms to be switched out.
Pole Inspection
Much of our pole-replacement work comes from pole inspection reports. Like most utilities that installed large numbers of wood poles back in the 1950s, 1960s and 1970s, Aquila now has a maturing population of poles that need to be refurbished or replaced. Every three to eight years, depending on the size and age of the pole line, a certified inspection and treatment contractor inspects all of Aquila’s wood poles. A double-circuit line requires inspection more frequently than a single secondary circuit.
Depending on the pole-line’s age, the inspection contract may vary from a visual top-to-bottom aboveground survey, or a sounding and bore, to a partial belowground line excavation inspection. The inspector’s report, which identifies pole rejects and bad crossarms, and field reports turned in by crews where decay or gross defects have been noted, are distributed to maintenance and construction crews for replacement.
Aquila’s system in central Kansas is also expanding. While the expansion requires new pole installations for new customers and subdivisions, more often the system needs upgrading to meet the increased demand for capacity from its growing customer loads. From time to time a new highway widening or off-ramp will also make it necessary to relocate a pole line. However, the biggest challenge is to make sure the rotten poles are replaced to ensure the system is properly maintained so that the utility is prepared when Mother Nature calls.
Pole Replacement
A good example of our workload was a project in Greenleaf, Kansas. Aquila replaced approximately 10 poles and a few crossarms and rotten poles to upgrade the line. They were all distribution poles on a 2400-V/4160-V feeder. Most of the system was 3-phase, but there were a few single-phase poles.
Aquila’s maintenance and construction crew typically consists of a bucket truck, a digger derrick truck, a materials truck and maybe a pole trailer. All of Aquila’s crewmembers are trained to work both overhead and underground distribution as well as 345-kV transmission lines.
Almost all maintenance work is done on energized lines, so it is standard safety practice to work out of an insulated bucket, using coverups, line hose, and insulated gloves and sleeves. For this type of work, it is also important to wear leather gloves over the rubber gloves to protect the rubber gloves from abrasions and lacerations that may affect the insulating quality of the rubber gloves.
Temporary Conductor Support
No piece of pole hardware is more important when changing out an old pole than the fiberglass side arm, which is temporarily attached to the old pole with a strap hoist or chain binder. This “layout arm” is used to transfer the energized conductor off to the side while the new pole is placed in the ground. A “wire holder” at the end of the layout arm supports the conductor away from the work area. The layout arm is even more valuable in giving the lineman room to work, when additional crossarms and other pole-top equipment are involved.
Once the new pole is in place, the lineman transfers the conductor to the preformed conductor tie on the pole. He then cuts off the old pole to gain even more distance.
This procedure may vary from circuit to circuit, but at the end of the day, old poles are replaced and the system becomes healthier and stronger. When the winds blow in central Kansas, which they frequently do, our customers can rest assured that Aquila’s pole lines will still be standing.
Justin Mueting has just completed his apprenticeship with Aquila Inc. and is now a journeyman lineman. After attending MATC in Manhattan, Kansas, he went to work for Aquila in Phillipsburg, Kansas, where he worked for one year before transferring to the Concordia division, where he has been for the last two years. jmueting_72@yahoo.com