HVDC > HVDC References > North America > Pacific HVDC Intertie > Upgrading to 500 kV DC
Up until the first energy crisis in the mid -1970s power consumption was increasing strongly. A number of projects aimed at securing the long-term supply of power to Los Angeles were outlined. These were necessary not only to meet the demand, but also because it was desired to close down a number of older, uneconomical local power stations and to reduce dependence on oil-fired and gas thermal plants. It was against this background that it was decided to investigate new projects and also the possibility of raising the capacity of existing transmission schemes. Eventually it was agreed to raise the line voltage of the Pacific Intertie. This led to the creation of the Pacific Intertie Upgrade (PIU) project for which
TheCelilo station with Pacific Intertie Upgrade (PIU) in the foreground | ABB received the order.The PIU essentially consisted in putting a 100 kV 6-pulse thyristor converter in series with the three mercury arc converters in each pole. The upgrading was commissioned in 1985. |