HVDC > HVDC References > North America > Pacific HVDC Intertie > Original project
The largest ABB project with mercury-arc valves.
In 1965 ABB was awarded a contract together with General Electric for two converter stations for a 1440 MW, ± 400 kV transmission scheme, the Pacific Intertie. Although the technology was well established by then, the contract nevertheless represented a challenge to both the owners and the suppliers, since the line voltage, the line length and the line current were greater than for any previous HVDC project, making it the most complex yet. The site chosen for the northern terminal was The Dalles, Oregon, which lies close to several large power stations on the Columbia river, with Bonneville Power Administration (BPA) as owner. The southern terminal was located at Sylmar, in the northern tip of the Los Angeles basin. Sylmar is owned by five utilities, with the Los Angeles Department of Water and Power (LADWP) acting as the managing and operating agent.
Mercury-arc valve hall in Sylmar | The mercury-arc valve formed the basis of ABB's HVDC development work in the 1960s. When the contract for the Pacific Intertie was signed in 1965, 4-anode valves of this type for 125 kV and 1200 A, with two 6-pulse converters in series, were in operation. The bold step was now taken to adopt 6-anode valves designed for 1800 A and 133 kV per converter and with three groups in series, for a transmission scheme rated ±400 kV, 1440 MW. |
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ABB’s undertakings for the Pacific Intertie contract in 1965 included system studies and system responsibility, the manufacturing and supply of the converter (mercury-arc) valves plus special apparatus and the control equipment, and also the commissioning.
The transmission scheme entered into operation in 1970, but shortly after this (in 1971) the San Fernando earthquake devastated the Sylmar converter station. The station building was severely damaged, as was much of the equipment, and it was not until 1973 that the station was rebuilt and operation could be restored. After a few years of operation, the owners decided to make use of the inherent capacity of the equipment and raise the transmission rating to 2000 A and 1600 MW.
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The Celilo station in Oregon | The Sylmar station in Los Angeles |