Rehabilitation of flood-damaged hydroelectric generators

On October 2, 1998, the Bureau of Indian Affairs' Headgate Rock Powerplant experienced a massive breach of the penstock due to failure of the stub shaft of generating unit 2. The turbine shaft failure resulted in destruction of the turbine shaft seal, thereby allowing water into the powerplant via the turbine pit. The water level in the plant reached tailwater elevation, inundating the three generating units and excitation gallery, and partially flooding the station service gallery. The plant was under water for 2 weeks. This paper describe the procedures used to clean, dry, repair and test the generator stators in order to rehabilitate the units and return them to serviceable condition.