Feasibility studies and design services for the upgrade of an aging HVDC system

CU HVDC Transmission System – Valve and Control Replacement

Great River Energy’s (GRE) existing CU high-voltage direct current (HVDC) system was serves approximately 500,000 customers and transmits 73% of the community’s power. But, having been commissioned in 1978, the system needed an upgrade. We were engaged as owner’s engineer to find a solution that would minimize cost and customer impact.

Our team assessed which would be better: a replacement of the valves and controls or a full greenfield replacement. We assessed the station, obtained inputs from the major HVDC equipment suppliers, and prepared budgetary costs estimates and risk assessments. Based on our findings, we ultimately recommended a valve and control replacement.

We prepared technical specifications and tender documents, assisting in pre-bid meetings, site visits, and other project management needs. We performed design reviews, witnessed major equipment testing, and assisted on-site during commissioning.

The replacement was successfully executed in an extremely tight construction window scheduled to coincide with a 74-day power plant outage, resulting in minimal system impact. The new HVDC system will benefit GRE’s customers for years to come, requiring less energy to operate and maintaining the same world-class reliability they have come to expect.