Douglas County Public Utility District is conducting a program to rebuild generators and refurbish turbine parts at the ten-unit, 774-MW Wells hydroelectric project, on the Columbia River in Washington.
Douglas PUD awarded a $151 million contract to Toshiba International Corp. to rebuild and modernize the nine generators and to renew and refurbish turbine parts for all ten units, public information officer Meaghan Vibbert said.
The decision to rehabilitate the units originated from a February 2005 fault in Unit 1, the PUD said. The generator was rebuilt under a contract with National Electric Coil and returned to service in 2006.
Based on tests of Unit 1, and information indicating generator coils of the other nine units were approaching the end of their service lives, Douglas PUD concluded it would be necessary to rebuild the other nine generators.
Site work began in fall 2008; work is expected to be completed by 2016. Although modest improvements in efficiency are expected — less than 0.5 percent — the primary benefit of the rebuild will be the extension of equipment service life, Vibbert said.
Generators will be rewound with new copper coils, and steel cores will be restacked with new laminations.
Turbine components and water passages will be refurbished, replaced, or re-machined to extend the service life of each unit by 30 to 40 years. Douglas PUD previously installed modern high-efficiency replacement turbines in all ten units, completing that work in 1990.