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CU HVDC Transmission System ¨C 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.