Barkley hydropower rehabilitation gets a 270-ton lift
By Lee Roberts
KUTTAWA, Ky. — Work crews at Barkley Power Plant removed a 270-ton rotor assembly, Aug. 16, 2012 from a crippled hydropower unit damaged 18 months ago by an electrical fire. The heavy lift enables the U.S. Army Corps of Engineers Nashville District to move forward with the generator's rehabilitation.
The hour-long removal is one that the Corps did not take lightly. Power plant officials coordinated with the contractor, National Electric Coil from Columbus, Ohio, extensively leading up to the removal of the large rotor assembly.
The lift went perfectly without incident and was an amazing sight given the size and weight nearly reached the crane's capacity, which is 275 tons, said Steve Miller, Barkley Power Plant power project manager.
The Corps and contractor made sure the rotor assembly did not pinch or damage the hydropower unit as it lifted clear. The crane then moved it and secured it onto a pedestal where it will remain throughout the rehabilitation process.
Jody Robinson, Nashville District's project engineer, said the Corps took every precaution to ensure the safety of everyone involved with the lift.
"It's a pretty straight forward operation, but it's obviously pretty critical due to the load. The crane is made to do this," Robinson explained. "We went over the steps from A to Z."
With this piece of the operation complete, Robinson said the repair teams now have access to do the rewind of the unit, restack the core, then the rotor will go back into place, and the unit will be reassembled to go back into production. The estimated completion date is July 2013.
The power plant contains four General Electric generators with nameplate ratings of 32.5 megawatts. They were placed into service in 1966 with an estimated life cycle of 30 years.
In December 2010 the unit now being rehabilitated suffered a phase-to-ground fault resulting in a fire that damaged the generator windings. It remained inoperable until the Nashville District awarded the repair contract in October 2011.
Jamie James, Nashville District's project manager, said the equipment has operated since its initial installation with a great deal of reliability, and has performed beyond a typical design life of 30 years.
"That's a tribute to the men and women who have operated and maintained this equipment all this time," James said. "But even with the best of care, time and age catch up to mechanical and electrical components, and that's really what happened to unit one when we had the phase to ground that resulted in a fire."
The $11.5 million project to rehabilitate the power generator is funded using emergency operations and maintenance funds and customer funds made possible through a memorandum of agreement between the Corps, Southeastern Power Administration and their preference customers.
The memorandum allows SEPA, the organization who markets the Corps' hydropower, to forward preference customer funds for the rehabilitation, non-routine maintenance, and modernization of the Corps' hydropower projects in the Nashville District. In the next 20 years SEPA looks to direct more than $1.2 billion into Corps' projects including 28 hydropower generators the Corps operates and maintains.
The agreement guarantees low cost energy for customers while also providing up-to-date equipment. Power from the Corps' 28 units are generated for residents living in Tennessee, Kentucky, Mississippi, North Carolina, Alabama, Georgia, Virginia and Illinois.
James said the ongoing rehabilitation of the Barkley hydropower generator involves more disassembly, rewinding the generator, and then replacement parts have to be tested and manufactured before reassembly can take place next year.
"When we put this unit back into operation we'll be able to spread the generating capacity over all four of the units and reduce the wear and tear on the other units until we can complete the rehab on them, which is scheduled sometime into the future," James said.