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Customer Success Story

Improving power reliability for millions of West Coast residents

The world’s largest HVDC converter transformers provided to a major link in the US

The owners of the Celilo Converter Station decided to refurbish and upgrade the station capacity to 3,800 MW. To secure the reliability of power, the first major HVDC link in the US was installed. Hitachi Energy designed, manufactured and tested the world’s largest HVDC converter transformers for the project. A total of seven single phase, 770 MVA 3-winding transformers, were designed to fit in the existing area, which reduced the complexity of the installation and commissioning of the converter station.

The transformers offer lower losses, require less maintenance and will extend the lifetime of the HVDC link. The upgraded Celilo station, which is owned by Bonneville Power Administration, was successfully commissioned in 2016.

The Celilo converter, located near the Columbia River, is the northern station of the Pacific DC Intertie, a 1,360-kilometer HVDC link that connects to the Sylmar converter station in Los Angeles. It transmits electricity from the Pacific Northwest to as many as three million households in the greater Los Angeles area.

During winter, the north consumes significant quantities of power for heating while the south requires less, but in summer demand is reversed with more power needed in the south for cooling. The Pacific Intertie HVDC link enables the balance of supply with demand between these regions.

The Pacific Intertie was the first major HVDC link installed in the US.  It was originally commissioned by Hitachi Energy in 1970, and has been providing power to millions in the U.S. for nearly five decades. We are delighted to return to this pioneering project.

Main data


Bonneville Power Administration


HVDC converter transformers



Power rating

770 MVA, 560kV DC, 500/230kV AC


U.S California



Pacific Intertie – Celilo Upgrade: A lifetime with Hitachi Energy