Pacific Intertie
Encyclopedia
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
line that transmits electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
from the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
to the Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
area using high voltage direct current (HVDC). The line capacity is 3,100 megawatts, which is enough to serve two to three million Los Angeles households and is 48.7% of the Los Angeles Department of Water and Power
Los Angeles Department of Water and Power
The Los Angeles Department of Water and Power is the largest municipal utility in the United States, serving over four million residents. It was founded in 1902 to supply water and electricity to residents and businesses in Los Angeles and surrounding communities...
(LADWP) electrical system's peak capacity.
The intertie originates near the Columbia River
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
at the Celilo Converter Station
Celilo Converter Station
The Celilo Converter Station, built in 1970 and owned and operated by the Bonneville Power Administration, is the northern terminus of the Pacific DC Intertie, near The Dalles, Oregon, in the United States.-History:...
on Bonneville Power Administration
Bonneville Power Administration
The Bonneville Power Administration is an American federal agency based in the Pacific Northwest. BPA was created by an act of Congress in 1937 to market electric power from the Bonneville Dam located on the Columbia River and to construct facilities necessary to transmit that power...
's grid outside The Dalles, Oregon
The Dalles, Oregon
The Dalles is the largest city and county seat of Wasco County, Oregon, United States. The name of the city comes from the French word dalle The Dalles is the largest city and county seat of Wasco County, Oregon, United States. The name of the city comes from the French word dalle The Dalles is...
and is connected exclusively to the Sylmar Converter Station north of Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
, which is owned by five utility companies and managed by LADWP. The Intertie is capable of transmitting power in either direction, but power on the Intertie flows mostly from north to south.
The idea of shipping hydroelectric power to Southern California
Southern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...
had been proposed as early as the 1930s, but was opposed and scrapped. By 1961, U.S. president John F. Kennedy
John F. Kennedy
John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....
authorized a large public works project, using new high voltage direct current technology from Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. The project was undertaken as a close collaboration between General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
of the U.S. and ASEA
ASEA
Allmänna Svenska Elektriska Aktiebolaget was a Swedish industry company. It merged with the Swiss Brown, Boveri & Cie in 1988 to form Asea Brown Boveri...
of Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. Private California power companies opposed the project but their technical objections were rebutted by Uno Lamm
Uno Lamm
August Uno Lamm was a Swedish electrical engineer and inventor, sometimes called "The Father of High Voltage Direct Current" power transmission....
of ASEA at the IEEE meeting in New York in 1963. When completed in 1970 the combined AC and DC transmission system was estimated to save consumers in Los Angeles approximately U.S. $600,000 per day by use of electric power from projects on the Columbia River
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
.
The Pacific Intertie takes advantage of differing power demand patterns between the northwestern and southwestern U.S. During winter, the northern region operates electrical heating devices while the southern portion uses relatively little electricity. In summer, the north uses little electricity while the south reaches peak demand due to air conditioning usage. Any time the Intertie demand lessens, the excess is distributed elsewhere on the western power grid
Western Interconnection
The Western Interconnection is one of the two major alternating current power grids in North America. The other major wide area synchronous grid is the Eastern Interconnection...
(states west of the Great Plains, including Colorado and New Mexico).
Components
The Pacific Intertie consists of:- The Celilo Converter StationCelilo Converter StationThe Celilo Converter Station, built in 1970 and owned and operated by the Bonneville Power Administration, is the northern terminus of the Pacific DC Intertie, near The Dalles, Oregon, in the United States.-History:...
which converts three phase 60 Hz ACAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
at 235 to 525 kV to 500 kV DCDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
at 45°35′39"N 121°6′51"W. - The grounding system at Celilo consists of 1,067 cast iron anodes buried in a two foot trench of petroleum cokePetroleum cokePetroleum coke is a carbonaceous solid derived from oil refinery coker units or other cracking processes. Other coke has traditionally been derived from coal....
, which behaves as an electrode, arranged in a ring of 3255 m (2.02 mi) circumference at Rice Flats (near Rice, OregonRice, OregonRice is an unincorporated community in Wasco County, Oregon, United States.Rice was named for Horace Rice, who settled on upper Fifteenmile Creek in the 1860s and who planted the first crop of wheat in upland Wasco County. When the Great Southern Railroad established a line into the area in 1905,...
), which is 10.6 km (6.6 mi) SSE of Celilo. It is connected to the converter station by two aerial 644 mm2 steel-reinforced aluminum (ACSR) cables. - A 1362 kilometres (846.3 mi) overhead transmission line consisting of two uninsulated conductors each 1,171 mm2 in cross sectional area, containing a steel wire core for strength.
- The Sylmar Converter Station (34°18′39"N 118°29′21"W) which converts DC to AC (a process also called invertingInverter (electrical)An inverter is an electrical device that converts direct current to alternating current ; the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits....
) and phase-synchronized with the L.A. power grid. - The Sylmar grounding system is a line of 24 silicon-iron alloy electrodes submerged in the Pacific OceanPacific OceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
suspended in concrete enclosures about one meter above the ocean floor. The grounding array is 48 km (30 mi) from the converter station and is connected by a pair of 644 mm2 aluminum cables. - The combined wires have a capacity of 2 gigawatts in bipolar mode and 1.55 gigawatts with earth (ground) return.
History
Originally only mercury arc rectifiers were used as static inverterInverter (electrical)
An inverter is an electrical device that converts direct current to alternating current ; the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits....
valves. The valves were series connected in three six-pulse valve bridges for each pole. The blocking voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
of the valves was 133 kV with a maximum current of 1,800 ampere
Ampere
The ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...
s, for a transmission rate of 1,440 megawatts with a symmetrical voltage of 400 kV against earth. The line is the DC part of a system of four 500 kV lines that connect the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
with the Southwest; the AC
Alternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
part is Path 15
Path 15
Path 15 is an portion of the north-south power transmission corridor in California, U.S. It forms a part of the Pacific AC Intertie and the California-Oregon Transmission Project....
. This is one of two HVDC lines serving Los Angeles, the other is the Path 27.
- In 1972, after the Sylmar earthquakeSylmar earthquakeThe 1971 San Fernando earthquake struck the San Fernando Valley near Sylmar, California at 6:00:55 a.m. PST on February 9, 1971, with a magnitude of 6.6....
, the static inverter station in Sylmar had to be reconstructed after damage to the largest part. - In 1982, the power rating of the mercury arc valve rectifiers was raised by various improvements to 1,600 megawatts.
- In 1984, the transmission voltage was pushed to 500 kV and the transmission power was increased to 2,000 megawatts by adding one six-pulse thyristorThyristorA thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bistable switches, conducting when their gate receives a current trigger, and continue to conduct while they are forward biased .Some sources define silicon controlled rectifiers and...
valve group to each pole. - In 1989, a further increase of the transmission power took place by a parallel switched thyristor static converter in Celilo and Sylmar.
- In 2004, Sylmar East station situated at 34°18′42"N 118°28′53"W was upgraded from 1,100 MW to 3,100 MW (rededicated as the Sylmar Converter Station in 2005). The controls and older converters, including the mercury arc valves, were completely replaced by a single pair of 3,100 MW 12-pulse converters built by ABB. In parallel with this project, the six-pulse mercury arc valves at the Celilo Converter Station were replaced with Siemens light-triggered thyristors (MARP replacement).
External links
More on the ABB website on Pacific HVDC Intertie:- Abb.com
- Abb.com
- aerial photo of Sylmar inverter plant
- Wecc.biz
- http://web.archive.org/web/20050426045806/http://www.transmission.bpa.gov/cigresc14/Compendium/PACIFIC.htm
- http://web.archive.org/web/20050426161757/www.transmission.bpa.gov/cigresc14/Compendium/Pacific+Pictures.pdf
