Celilo Converter Station mercury arc valve replacement

The Pacific HVDC Intertie (PDCI) is the most complicated HVDC Scheme in the world. Decisions about changing the PDCI are further complicated by a complex ownership arrangement. The Intertie has the a capacity of 3100 MW and runs from the Celilo Converter Station in The Dalles, Oregon to the Sylmar Converter Station in Sylmar, California. After an earthquake damaged the Sylmar station a decision was made to rebuild it with consequences for the Celilo station. The biggest change that will take place at Celilo is to make a one-for-one replacement of the mercury arc valves. The replacement light triggered thyristor valves will be constructed on rolling platforms like the mercury arc valves to permit quick installation. Installation of the thyristor valves is also being used to replace the maintenance-intensive wet surface coolers for all of the valves in the station.