2024-005 - AH3 Teardown and Overhaul

In 2024, YEC will be performing a major overhaul on the AH3 Hydro Unit. A stamped scope of work is included in Appendix 6. This scope of work presented in Appendix 6 outlines desired outcomes of the overhaul as well as general and technical requirements of the site contractor for supplying specialized work, materials and documentation leading up to the site work and during the site work and project closeout stages. 

The Aishihik Generating Station is located approximately 145 km west of Whitehorse. The power plant is installed approximately 356ft underground and is accessed by a service elevator and crane shaft through a service building on the surface. The station has three Francis hydro turbines generators, AH1, AH2, AH3. AH1 and AH2 are 15 MW vertical units and were originally installed in the 1970s and they have both been fully overhauled over the last two years. AH3 is a horizontal Francis turbine-generator originally installed in 2010. AH3 operates under a rated head of 180.44 m and spins at 900 rpm. The turbine is rated at 7180 kW and the generator has a 8250 kVA rating at 0.85 PF with a 13.8 kV output. The generator has a PMG and brushless exciter with a silicon rectifier. To date, no major overhauls have been performed on the AH3 unit since original commissioning.