Celilo Converter Station
The Celilo Converter Station, built in 1970 and owned and operated by the Bonneville Power Administration, is the northern terminus of the Pacific DC Intertie, near The Dalles, Oregon, in the United States.
The Celilo Converter Station was originally configured with six groups of six-pulse mercury arc valves with a blocking voltage of 133 kV each (for a total of ±400 kV) and a maximum current of 2,000 amperes.
Until September 2001, the Celilo Converter Station was partially open to the public and included displays describing the history of DC transmission and the Pacific Intertie, but security concerns have closed this facility to the public.
In 2004, the mercury arc valves groups were replaced with light-triggered thyristor groups to eliminate the environmental risks of mercury and to reduce the maintenance costs of the obsolete mercury arc valves.
There was also a DC test facility for testing high voltage equipment nearby (now abandoned, soon to be demolished). At the end of the 1960s, a test transmission line for 1,333 kV was erected at in order to test equipment for this voltage, which was to be used for a planned HVDC from Celilo Converter Station to Hoover Dam. This line, however, was never built.