Interstate Power and Light Company (IPL) of Iowa concluded rebuild work and re-energized a 20-mile stretch of 345 kilovolt (kV) transmission line in Poweshiek County, Iowa. The transmission line was severely damaged on Feb. 24, 2007, during a major Midwest winter storm.
As part of the project, IPL rebuilt 82 steel H-Frame transmission structures weighing a total of approximately 3.2 million pounds. With the assistance of helicopters, IPL strung nearly 160 miles of conductor and static wire, equivalent to the distance from Des Moines, Iowa, to the Quad Cities. IPL also installed approximately 300 insulators, which are used to attach the conductor to each of the transmission structures.
IPL completed the redesign and rebuild of the transmission line in less than five months. Rebuild projects of this magnitude typically require 18–30 months to design and construct. Up to 50 workers were on-site, working seven days a week. The workers accumulated a total of more than 45,000 man-hours to complete the project as safely and quickly as possible. IPL’s share of the cost of the rebuild project is approximately $10 million.
IPL completed its initial restoration efforts on March 7, 2007. Permanent repairs to the system will continue through the end of the year. EC