Pacific HVDC intertie

Although not the first HVDC transmission scheme, the Pacific HVDC Intertie (PDCI) has been the subject of keen interest from the HVDC community from its earliest days. The initial configuration has been repeatedly altered over a period of more than 30 years as a result of various upgrades and in response to two major earthquakes, a fire, and environmental concerns. Once a museum of HVDC technology development, the PDCI now contains the most modern equipment available. The owners of the southern converter station at Sylmar, California, have completely rebuilt the station, replacing nearly all of the converter equipment with modern high-power converters. At the northern end of the Intertie, at the Celilo converter station in The Dalles, Oregon, the changes have been more modest. This article traces the story of the creation of the PDCI and the subsequent changes that have taken the capacity from 1,440 MW in 1970 to 3,100 MW today