Pacific DC Intertie
The Pacific DC Intertie, also known as Path 65, a high voltage direct current transmission line ( HVDC) in the western U.S. is what serves electrical energy from the northern U.S. to transport in the greater Los Angeles area. The line begins in the north of the state of Oregon at the Celilo Converter Station near the Columbia River and ends after 1362 km in the south of California in Sylmar location in the vicinity of Los Angeles. It is operated by the Bonneville Power Administration and the Los Angeles Department of Water and Power ( LADWP ). The transmission capacity of the HVDC is a maximum of 3100 MW, which corresponded to approximately 2/3 of the electricity needs of Greater Los Angeles in 2006.
The HVDC consists of two conductors and can be both monopolar with 500 kV and the ground as the return conductor, and operated with bipolar ± 500 kV with a maximum power of 2000 MW. In monopolar operation with use of the earth electrode to the output per head of 1550 MW or 1000 MW when using both wire without grounding. The current per conductor, it can be used for bundled conductor with two conductor cables, a maximum of 3.1 kA.
In monopolar operating at maximum power, a large current flows through the earth electrode. The grounding system in Celilo is located at a distance of 10 km to the converter station in the form of a metallic iron ring with a diameter of 3255 m in the ground. To prevent the electrolysis, which would destroy the metallic ground electrode, the metallic conductor is embedded in coke which makes electrical contact with the surrounding soil. The grounding resistance is 0.43 Ω. The grounding system in the south, is 48 km from the converter station in the Pacific Ocean and has a grounding resistance of 1.13 Ω on.
The plant was put into operation in 1970 and was originally equipped with mercury vapor rectifiers. In 1972, the converter station had to be rebuilt after an earthquake in Sylmar for the most part. In 1985, the mercury arc rectifiers were replaced by more powerful thyristors, 1989 was extended by parallel converter.
Manufacturer of the converter stations are the Swedish company Svenska Allmänna Elektriska Aktiebolaget ( ASEA ), now Asea Brown Boveri (ABB), and General Electric.
In addition to the HVDC Pacific DC Intertie exists in the western United States nor the HVDC Intermountain (Path 26) between Utah and Adelanto in California.