RECONSTRUCTION MILESTONE: SUBTRANSMISSION SYSTEM BACK TO NORMAL ON FEBRUARY 2, 2007
Wow! What a relief! The first important piece of getting Twin Valleys Public Power District’s system back to normal was completed last week. The ice storm on December 29, 2006 heavily damaged three segments of the subtransmission system. Damage was severe enough to close three roads in Harlan County.
The first segment to be rebuilt was a 34.5 kV line that feeds the substation southwest of Ragan. This was important to the restoration of power in southern Phelps and northern Harlan Counties as this substation was needed to provide power to this area. Crews from Twin Valleys Public Power District and Southwest Public Power District were used to accomplish this.
The second segment that was rebuilt, north of Alma, was a 69kV line. Most of this line was on the ground after the storm. It was temporarily rebuilt after the storm by crews from Twin Valleys Public Power District and McCook Public Power District. The original design engineer, who is now retired, was called upon to assist with redesigning and improving the line to lessen the likelihood of a future failure. Hutton Contracting Company of Sterling, Colorado rebuilt this segment.
The third segment to be rebuilt was the 69kV line from the substation northeast of Alma to Republican City. This segment of line had the most overall damage and was redesigned for Twin Valleys Public Power District by another retired consulting engineer. A crew from Twin Valleys Public Power District staked this line for construction. The new design will make the line stronger to avoid future problems. Reconstruction of this line was completed by Hutton Contracting.
Much of the distribution system that was heavily damaged is being redesigned by Twin Valleys Public Power District. Spans are being shortened and /or pole diameters are being increased. In some cases, T2 type conductor is being installed, which is less prone to ice damage. In these damaged areas, copper and steel conductor is being replaced with higher strength aluminum with a steel center core.
Approximately 52 miles of 3 phase line was on the ground after the ice storm. So far about 30 miles have been rebuilt by Hutton Contracting, Kayton Electric of Holdrege and crews from Twin Valleys Public Power District with assistance of Frenchman-Cambridge Irrigation District employees. These crews are working from 7 a.m. to 6 p.m.
The single phase lines are being rebuilt by crews from Twin Valleys Public Power District and McCook Public Power District with assistance of employees from Frenchman-Cambridge. Another contractor, C&M Pole Line Construction from Shawnee, Oklahoma, will begin rebuilding single phase lines on February 6th.
As the daylight hours increase, more progress will be made at getting Twin Valleys Public Power District system repaired and back to normal. With the Improvements that are being made the system, it should be able to withstand weather related problems better in the future.
As a safety concern, many of the lines that have not been permanently repaired are low or on the ground. Be alert, some of these lines may be energized.
