upgraded介绍美国(用英文)

介绍美国(用英文)

The Western USA interconnection (Pacific Intertie) The AC/DC Pacific Intertie is the largest single electricity transmission program in the United States. For over 30 years, electricity consumers on the US West Coast have benefited from a power link that allows large amounts of power to be transmitted between the Pacific Northwest and the Southwest. The high-voltage transmission lines that make this power-sharing possible collectively are called the Pacific Intertie. The Intertie includes three AC lines and one HVDC line. Together, prise the largest single electricity transmission program in the United States. The Intertie is capable of transmitting up to 7,900 MW - 4,800 on AC and 3,100 on DC. Because large amounts of Northwest hydro power can be transmitted reliably to the Southwest, less power has been generated at fossil-fuel power plants - an important benefit in a part of the country with air pollution problems. Conversely, because the Northwest has been able to import power from California, particularly overnight when demand is low, water can be reserved in reservoirs that otherwise would be used to make electricity. From time to time the power has also been going northwards when the Northwest has been lacking hydro power. The initial Intertie consisted of two 500 kV AC lines and one ±400 kV DC line linking Oregon with Los Angeles. The northern end of the DC line is at the Bonneville Power Administration’s Celilo Converter Station, which is just south of The Dalles Dam about 90 miles east of Portland. The southern end is 846 miles (1361 km) away at the Sylmar Converter Station on the northern outskirts of Los Angeles. That station is operated by utilities including the Los Angeles Department of Water and Power (LADWP) and Southern California Edison. The northern end of the AC Intertie is at the John Day Substation, 30 miles (48 km) east of the DC terminal Celilo. Two AC lines run south from John Day to Lugo, east of Los Angeles. These lines went into service in 1968 and 1969, at bined total capacity of 2,500 MW. A third line from The Dalles Dam to Tesla, east of San Francisco, pleted in 1993 and brought the total AC capacity to 4,800 MW.