Continental U.S. power transmission grid

Last updated June 19, 2019

The two major and three minor NERC interconnections, and the nine NERC Regional Reliability Councils. NERC-map-en.svg — The two major and three minor NERC interconnections, and the nine NERC Regional Reliability Councils.

The electric power transmission grid of the contiguous United States consists of 120,000 miles (190,000 km) of lines operated by 500 companies. UnitedStatesPowerGrid.jpg — The electric power transmission grid of the contiguous United States consists of 120,000 miles (190,000 km) of lines operated by 500 companies.

The electrical grid that powers mainland North America is divided into multiple wide area synchronous grids. The Eastern Interconnection and the Western Interconnection are the largest. Three other regions include the Texas Interconnection, the Quebec Interconnection, and the Alaska Interconnection. Each region delivers power at a nominal 60 Hz frequency. The regions are not usually directly connected or synchronized to each other, but there are some HVDC interconnections.

An electrical grid, or electric grid, is an interconnected network for delivering electricity from producers to consumers. It consists of

North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It is also considered by some to be a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.

Wide area synchronous grid Regional electrical grid

A wide area synchronous grid is a three-phase electric power grid that has regional scale or greater that operates at a synchronized frequency and is electrically tied together during normal system conditions. Also known as synchronous zones, the most powerful is the synchronous grid of Continental Europe (ENTSO-E) with 667 gigawatts (GW) of generation, while the widest region served being that of the IPS/UPS system serving countries of the former Soviet Union. Synchronous grids with ample capacity facilitate electricity market trading across wide areas. In the ENTSO-E in 2008, over 350,000 megawatt hours were sold per day on the European Energy Exchange (EEX).

In the United States^[1] and Canada,^[2] national standards specify that the nominal voltage supplied to the consumer should be 120 V and allow a range of 114 V to 126 V (RMS) (−5% to +5%). Historically 110 V, 115 V and 117 V have been used at different times and places in North America. Mains power is sometimes spoken of as 110 V; however, 120 V is the nominal voltage.

History

In the United States in the 1920s, utilities formed joint-operations to share peak load coverage and backup power. In 1934, with the passage of the Public Utility Holding Company Act (USA), electric utilities were recognized as public goods of importance and were given outlined restrictions and regulatory oversight of their operations. The Energy Policy Act of 1992 required transmission line owners to allow electric generation companies open access to their network^[3]^[4] and led to a restructuring of how the electric industry operated in an effort to create competition in power generation. No longer were electric utilities built as vertical monopolies, where generation, transmission and distribution were handled by a single company. Now, the three stages could be split among various companies, in an effort to provide fair accessibility to high voltage transmission.^[5]^:21 The Energy Policy Act of 2005 allowed incentives and loan guarantees for alternative energy production and advance innovative technologies that avoided greenhouse emissions.

In economics, a public good is a good that is both non-excludable and non-rivalrous in that individuals cannot be excluded from use or could be enjoyed without paying for it, and where use by one individual does not reduce availability to others or the goods can be effectively consumed simultaneously by more than one person. This is in contrast to a common good which is non-excludable but is rivalrous to a certain degree.

The Energy Policy Act, effective October 24, 1992, is a United States government act. It was passed by Congress and set goals, created mandates, and amended utility laws to increase clean energy use and improve overall energy efficiency in the United States. The Act consists of twenty-seven titles detailing various measures designed to lessen the nation's dependence on imported energy, provide incentives for clean and renewable energy, and promote energy conservation in buildings.

The Energy Policy Act of 2005 is a bill passed by the United States Congress on July 29, 2005, and signed into law by President George W. Bush on August 8, 2005, at Sandia National Laboratories in Albuquerque, New Mexico. The act, described by proponents as an attempt to combat growing energy problems, changed US energy policy by providing tax incentives and loan guarantees for energy production of various types.

In 2009, the Wall Street Journal reported that spies from China and Russia, as well as from other countries, "penetrated the U.S. electrical grid and left behind software programs that could be used to disrupt the system." According to U.S. officials, the spies didn't seek to damage the power grid; however they might be able to do so during a war or crisis. Most of the intrusions were detected by American intelligence agencies.^[6]

North American Electric Reliability Corporation

The North American Electric Reliability Corporation (NERC) is a nonprofit corporation based in Atlanta, Georgia, and formed on March 28, 2006, as the successor to the National Electric Reliability Council (also known as NERC) which formed in the wake of the first large scale blackout in November of 1965. The original NERC was formed on June 1, 1968, by the electric utility industry to promote the reliability and adequacy of bulk power transmission in the electric utility systems of North America. NERC's mission states that it is to "ensure the reliability of the North American bulk power system."^[7]

NERC oversees eight regional reliability entities and encompasses all of the interconnected power systems of the contiguous United States, Canada and a portion of Baja California in Mexico.

The United States of America (USA), commonly known as the United States or America, is a country comprising 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the most populous city is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.

Canada is a country in the northern part of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres, making it the world's second-largest country by total area. Canada's southern border with the United States, stretching some 8,891 kilometres (5,525 mi), is the world's longest bi-national land border. Its capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. As a whole, Canada is sparsely populated, the majority of its land area being dominated by forest and tundra. Consequently, its population is highly urbanized, with over 80 percent of its inhabitants concentrated in large and medium-sized cities, with 70% of citizens residing within 100 kilometres (62 mi) of the southern border. Canada's climate varies widely across its vast area, ranging from arctic weather in the north, to hot summers in the southern regions, with four distinct seasons.

Mexico, officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometers (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the tenth most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.

NERC's major responsibilities include working with all stakeholders to develop standards for power system operation, monitoring and enforcing compliance with those standards, assessing resource adequacy, and providing educational and training resources as part of an accreditation program to ensure power system operators remain qualified and proficient. NERC also investigates and analyzes the causes of significant power system disturbances in order to help prevent future events.

Eastern Interconnection

The Eastern Interconnection is one of the two major alternating-current (AC) electrical grids in North America.

All of the electric utilities in the Eastern Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency operating at an average of 60 Hz. The Eastern Interconnection reaches from Central Canada eastward to the Atlantic coast (excluding Quebec), south to Florida, and back west to the foot of the Rockies (excluding most of Texas).

Interconnections can be tied to each other via high-voltage direct current power transmission lines (DC ties), or with variable-frequency transformers (VFTs), which permit a controlled flow of energy while also functionally isolating the independent AC frequencies of each side. The Eastern Interconnection is tied to the Western Interconnection with six DC ties, to the Texas Interconnection with two DC ties, and to the Quebec Interconnection with four DC ties and a VFT.

On October 17, 2009, the Tres Amigas SuperStation was announced to connect the Eastern, Western and Texas Interconnections via three 5 GW superconductor links.^[8]

Western Interconnection

The Western Interconnection is the other major alternating current (AC) power grid in North America.

All of the electric utilities in the Western Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency of 60 Hz. The Western Interconnection stretches from Western Canada south to Baja California in Mexico, reaching eastward over the Rockies to the Great Plains.

Interconnections can be tied to each other via high-voltage direct current power transmission lines (DC ties) such as the north-south Pacific DC Intertie, or with variable-frequency transformers (VFTs), which permit a controlled flow of energy while also functionally isolating the independent AC frequencies of each side. There are six DC ties to the Eastern Interconnect in the US and one in Canada,^[9] and there are proposals to add four additional ties.^[10] 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 links.^[8]

Texas Interconnection

The Texas Interconnection is one of the three minor alternating current (AC) power grids in North America.

All of the electric utilities in the Texas Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency operating at an average of 60 Hz. The Texas Interconnection covers most of the state of Texas.

Interconnections can be tied to each other via high-voltage direct current power transmission lines (DC ties), or with variable-frequency transformers (VFTs), which permit a controlled flow of energy while also functionally isolating the independent AC frequencies of each side. The Texas Interconnection is tied to the Eastern Interconnection with two DC ties, and has a DC tie and a VFT to non-NERC systems in Mexico. There is one AC tie switch in Dayton, Texas that has been used only one time in its history (after Hurricane Ike).

On October 13, 2009, the Tres Amigas SuperStation was announced to connect the Eastern, Western and Texas Interconnections via three 5 GW superconductor links.^[8]

Quebec Interconnection

The Québec Interconnection is one of the three minor alternating-current (AC) electrical grids in North America.

The Quebec Interconnection covers all of the Province of Quebec and operates at an average system frequency of 60 Hz. It connects 18 systems in the US and Canada to one electric utility company: Hydro-Québec. It is operated as an independent AC grid for physical reasons.^[11] Because of its unique status, it is often functionally considered part of the Eastern Interconnection.

The Quebec Interconnection is tied to the Eastern Interconnection with four high-voltage direct current power transmission lines (DC ties), and with one variable-frequency transformers (VFTs) line, which isolate the unsynchronized AC frequencies of each side.

Alaska Interconnection

The Alaska Interconnection is one of the three minor alternating-current (AC) electrical grids in North America.

It is composed of two grids isolated from each other and from the rest of North American grids.

Related Research Articles

Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines which facilitate this movement are known as a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is known as the "power grid" in North America, or just "the grid". In the United Kingdom, India,Tanzania, Myanmar, Malaysia and New Zealand, the network is known as the "National Grid".

A high-voltage, direct current (HVDC) electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current (AC) systems. For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. For underwater power cables, HVDC avoids the heavy currents required to charge and discharge the cable capacitance each cycle. For shorter distances, the higher cost of DC conversion equipment compared to an AC system may still be justified, due to other benefits of direct current links. HVDC currently uses voltages between 100 kV and 800 kV, with an 1,100 kV link in China due to become operational in 2019.

North American Electric Reliability Corporation organization

The North American Electric Reliability Corporation (NERC) is a nonprofit corporation based in Atlanta, Georgia, and formed on March 28, 2006, as the successor to the North American Electric Reliability Council. The original NERC was formed on June 1, 1968, by the electric utility industry to promote the reliability and adequacy of bulk power transmission in the electric utility systems of North America. NERC's mission states that it is to "ensure the reliability of the North American bulk power system."

Electric power distribution Final stage of electricity delivery to individual consumers in a power grid

Electric power distribution is the final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2 kV and 35 kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises. Distribution transformers again lower the voltage to the utilization voltage used by lighting, industrial equipment or household appliances. Often several customers are supplied from one transformer through secondary distribution lines. Commercial and residential customers are connected to the secondary distribution lines through service drops. Customers demanding a much larger amount of power may be connected directly to the primary distribution level or the subtransmission level.

The electric power industry covers the generation, transmission, distribution and sale of electric power to the general public and industry. The commercial distribution of electric power started in 1882 when electricity was produced for electric lighting. In the 1880s and 1890s, growing economic and safety concerns lead to the regulation of the industry. What was once an expensive novelty limited to the most densely populated areas, reliable and economical electric power has become an essential aspect for normal operation of all elements of developed economies.

Utility frequency frequency used on standard electricity grid in a given area

The utility frequency, (power) line frequency or mains frequency is the nominal frequency of the oscillations of alternating current (AC) in an electric power grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains power around the world.

15 kV AC railway electrification railway electrification system is used in Germany, Austria, Switzerland, Sweden and Norway

Railway electrification systems using alternating current (AC) at 15 kilovolts (kV) and 16.7 Hertz (Hz) are used on transport railways in Germany, Austria, Switzerland, Sweden, and Norway. The high voltage enables high power transmission with the lower frequency reducing the losses of the traction motors that were available at the beginning of the 20th century. Railway electrification in late 20th century tends to use 25 kV, 50 Hz AC systems which has become the preferred standard for new railway electrifications but extensions of the existing 15 kV networks are not completely unlikely. In particular, the Gotthard Base Tunnel still uses 15 kV, 16.7 Hz electrification.

A variable-frequency transformer (VFT) is used to transmit electricity between two alternating current frequency domains. The VFT is a relatively recent development. Most asynchronous grid inter-ties use high-voltage direct current converters, while synchronous grid inter-ties are connected by lines and "ordinary" transformers, but without the ability to control power flow between the systems.

The Texas Interconnection is an alternating current (AC) power grid – a wide area synchronous grid – that covers most of the state of Texas. The grid is managed by the Electric Reliability Council of Texas (ERCOT).

The Eastern Interconnection is one of the two major alternating-current (AC) electrical grids in the continental U.S. power transmission grid. The other major interconnection is the Western Interconnection. The three minor interconnections are the Quebec, Alaska, and Texas interconnections.

The Western Interconnection is a wide area synchronous grid and one of the two major alternating current (AC) power grids in the continental U.S. power transmission grid. The other major wide area synchronous grid is the Eastern Interconnection. The three minor interconnections are the Québec Interconnection, the Texas Interconnection, and the Alaska Interconnection.

The Florida Reliability Coordinating Council (FRCC) is one of 8 Regional Entities delegated authority to insure reliability by North American Electric Reliability Corporation (NERC) in North American and was formed on September 16, 1996. The area served by FRCC was previously served by SERC Reliability Corporation (SERC). NERC and the regional reliability councils were formed following the Northeast Blackout of 1965. FRCC's offices are located in Tampa, Florida.

The Midwest Reliability Organization (MRO) began operations on January 1, 2005, as the successor to the Mid-continent Area Power Pool (MAPP), which was formed in 1965. MRO is one of seven regional electric reliability councils under North American Electric Reliability Corporation (NERC) authority. NERC and the regional reliability councils were formed following the Northeast Blackout of 1965. MRO's offices are located in St.Paul, Minnesota. MRO members include municipal utilities, cooperatives, investor-owned utilities, a federal power marketing agency, Canadian Crown Corporations, and independent power producers.

The Northeast Power Coordinating Council (NPCC) was formed January 19, 1966, as a successor to the Canada–United States Eastern Interconnection (CANUSE). NPCC is one of nine regional electric reliability councils under North American Electric Reliability Corporation (NERC) authority. NERC and the regional reliability councils were formed following the Northeast Blackout of 1965. NPCC's offices are located in New York City, New York.

The Southwest Power Pool (SPP) is the founding member of the North American Electric Reliability Corporation (NERC).

A grid-tie inverter converts direct current (DC) into an alternating current (AC) suitable for injecting into an electrical power grid, normally 120 V RMS at 60 Hz or 240 V RMS at 50 Hz. Grid-tie inverters are used between local electrical power generators: solar panel, wind turbine, hydro-electric, and the grid.

Hydro-Québec's electricity transmission system is an international power transmission system centred in Quebec, Canada. The system pioneered the use of very high voltage 735 kV alternating current (AC) power lines that link the population centres of Montreal and Quebec City to distant hydroelectric power stations like the Daniel-Johnson Dam and the James Bay Project in northwestern Quebec and the Churchill Falls Generating Station in Labrador.

The Tres Amigas SuperStation is a planned project to unite North America’s two major power grids and one minor grid, with the goal to enable faster adoption of renewable energy and increase the reliability of the U.S. grid. The project will use superconducting wires from Massachusetts-based American Superconductor Corp for electrical distribution and to interconvert alternating current (AC) and direct current (DC) power.

References

↑ ANSI C84.1: American National Standard for Electric Power Systems and Equipment—Voltage Ratings (60 Hertz) Archived July 27, 2007, at the Wayback Machine , NEMA (costs $83 for access)
↑ CSA CAN3-C235-83: Preferred Voltage Levels for AC Systems, 0 to 50 000 V
↑ Borberly, A. and Kreider, J. F. (2001). Distributed Generation: The Power Paradigm for the New Millennium. CRC Press, Boca Raton, Florida. 400 pgs.
↑ Mazer, A. (2007). Electric Power Planning for Regulated and Deregulated Markets. John, Wiley, and Sons, Inc., Hoboken, NJ. 313pgs.
↑ . (2001). Glover J. D., Sarma M. S., Overbye T. J. (2010) Power System and Analysis 5th Edition. Cengage Learning. Pg 10.
↑ Gorman, Siobhan (2009-04-08). "Electricity Grid in U.S. Penetrated By Spies" (PDF). The Wall Street Journal. Retrieved 2018-05-02.
↑ http://www.nerc.com/
1 2 3 High-Temp Superconductors To Connect Power Grids
↑
↑ Visualizing The U.S. Electric Grid
↑ "Control Area Concepts and Obligations" (PDF). North American Electric Reliability Council. July 1992. Retrieved July 18, 2011. Today, in NERC, there are four major interconnected areas: the Eastern Interconnection, the Western Interconnection, the Texas Interconnection, and the Québec Interconnection.

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[1] ANSI C84.1: American National Standard for Electric Power Systems and Equipment—Voltage Ratings (60 Hertz) Archived July 27, 2007, at the Wayback Machine , NEMA (costs $83 for access)

[2] CSA CAN3-C235-83: Preferred Voltage Levels for AC Systems, 0 to 50 000 V

[Distributed_Generation-3] Borberly, A. and Kreider, J. F. (2001). Distributed Generation: The Power Paradigm for the New Millennium. CRC Press, Boca Raton, Florida. 400 pgs.

[Electric_Power_Planning-4] Mazer, A. (2007). Electric Power Planning for Regulated and Deregulated Markets. John, Wiley, and Sons, Inc., Hoboken, NJ. 313pgs.

[History_of_Electric_Power_Systems-5] . (2001). Glover J. D., Sarma M. S., Overbye T. J. (2010) Power System and Analysis 5th Edition. Cengage Learning. Pg 10.

[6] Gorman, Siobhan (2009-04-08). "Electricity Grid in U.S. Penetrated By Spies" (PDF). The Wall Street Journal. Retrieved 2018-05-02.

[nercwebpage-7] ttp://www.nerc.com/

[hardware.slashdot.org-8] 1 2 3 High-Temp Superconductors To Connect Power Grids

[9] ↑

[10] Visualizing The U.S. Electric Grid

[11] "Control Area Concepts and Obligations" (PDF). North American Electric Reliability Council. July 1992. Retrieved July 18, 2011. Today, in NERC, there are four major interconnected areas: the Eastern Interconnection, the Western Interconnection, the Texas Interconnection, and the Québec Interconnection.