Teshmont has been providing specialist engineering services to Manitoba Hydro for the Nelson River Transmission Project since 1966. Teshmont’s initial services included feasibility studies, system definition studies, detailed engineering design, electrical and structural design of the HVDC lines and stations, and construction supervision and commissioning of the complete system. The project consisted of two HVDC transmission lines with a total length of about 1800 km, and three HVDC converter stations associated with the two bipoles. Bipole I is rated at ±450 kV, 1800 MW and Bipole II is rated at ±500 kV, 2000 MW.
When Bipole I was built, mercury arc valves were used to rectify the alternating current.
The mercury arc valves of Pole 1 were replaced with thyristor valves by GEC Alsthom, increasing the maximum power and voltage of the line to its present levels.
Teshmont was retained to assist with the replacement of the Bipole I Pole 1 mercury arc valves at the Dorsey and Radisson converter stations with advanced technology thyristor valves. Teshmont assisted with feasibility/justification of the project, preparation of the specifications for the replacement of the mercury-arc converter valves, bid evaluation, post award engineering, including review of contractor’s study reports, equipment specifications, test specifications and test reports, witnessing of tests and factory inspection, preparation of installation work packages and decommissioning instructions for removing existing mercury arc valve equipment and replacement with new thyristor valve equipment, as well as providing assistance to the sites during construction and commissioning phases.
After the Bipole I Pole 1 valve replacement project was complete, the mercury arc valves of Pole 2 were replaced with Siemens light triggered thyristor valves.
Teshmont assisted with the replacement of the Bipole I Pole 2 valves with advanced technology thyristor valves, and provided Manitoba Hydro with the same specialist services as for Pole 1.
Client: Manitoba Hydro
Geographical Region: North America