The Western Interconnection is one of the two major alternating current (AC)
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
power grids in North America. The other major wide area synchronous grid
Wide area synchronous grid
A wide area synchronous grid, also called an "interconnection" in North America, is a power grid at a regional scale or greater that operates at a synchronized frequency and is electrically tied together during normal system conditions...
is the Eastern Interconnection
The Eastern Interconnection is one of the two major alternating current power grids in North America. The other major interconnection is the Western Interconnection...
. The three minor interconnections are the Québec Interconnection
The Québec Interconnection is one of the three minor alternating current power grids in North America. The other two minor interconnections are the Texas Interconnection and the Alaska Interconnection...
, the Texas Interconnection
The Texas Interconnection is one of the three minor alternating current power grids in North America. The other two minor interconnections are the Québec Interconnection and the Alaska Interconnection...
, and the Alaska Interconnection.
All of the electric utilities in the Western Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency of 60Hz. The Western Interconnection stretches from Western Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
south to Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, reaching eastward over the Rockies
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
to the Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
Interconnections can be tied to each other via high-voltage direct current
High-voltage direct current
A high-voltage, direct current electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems. For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses...
power transmission lines (DC ties), or with variable frequency transformer
Variable frequency transformer
A variable frequency transformer is used to transmit electricity between two alternating current domains. The VFT is a relatively recent development...
s (VFTs), which permit a controlled flow of energy while also functionally isolating the independent AC frequencies of each side. The Western Interconnection is tied to the Eastern Interconnection with six DC ties. It is not tied to the Alaska Interconnection.
On October 13, 2009, the Tres Amigas SuperStation was announced to connect the Eastern, Western and Texas Interconnections via three 5 GW superconductor
Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
- North American Electric Reliability Corporation (NERC)
- Western Electricity Coordinating Council (WECC)Western Electricity Coordinating CouncilThe Western Electricity Coordinating Council was formed on April 18, 2002, from the merger of the Western Systems Coordinating Council which itself was formed on August 14, 1967, the Southwest Regional Transmission Association , and Western Regional Transmission Association...