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 that facilitate this movement form 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 part of electricity delivery, known as the electrical grid.
Mains electricity or utility power, power grid, domestic power, and wall power, or in some parts of Canada as hydro, is a general-purpose alternating-current (AC) electric power supply. It is the form of electrical power that is delivered to homes and businesses through the electric grid in many parts of the world. People use this electricity to power everyday items—such as domestic appliances, televisions and lamps—by plugging them into a wall outlet.
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 and 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 commodity sold is actually energy, not power, e.g. consumers pay for kilowatt-hours, power multiplied by time, which is energy. The commercial distribution of electricity 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.
A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Between the generating station and consumer, electric power may flow through several substations at different voltage levels. A substation may include transformers to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages. They are a common component of the infrastructure, for instance there are 55,000 substations in the United States.
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc lamp street lighting running on high-voltage alternating current (AC), and large-scale low-voltage direct current (DC) indoor incandescent lighting being marketed by Thomas Edison's company. In 1886, the Edison system was faced with new competition: an alternating current system initially introduced by George Westinghouse's company that used transformers to step down from a high voltage so AC could be used for indoor lighting. Using high voltage allowed an AC system to transmit power over longer distances from more efficient large central generating stations. As the use of AC spread rapidly with other companies deploying their own systems, the Edison Electric Light Company claimed in early 1888 that high voltages used in an alternating current system were hazardous, and that the design was inferior to, and infringed on the patents behind, their direct current system.
NSTAR was a utility company that provided retail electricity and natural gas to 1.4 million customers in eastern and central Massachusetts, including the Boston urban area. NSTAR became a subsidiary of Northeast Utilities in April 2012. In February 2015, Northeast Utilities and all of its operating companies became one large company known as Eversource Energy.
Eversource Energy is a publicly traded, Fortune 500 energy company headquartered in Hartford, Connecticut, and Boston, Massachusetts, with several regulated subsidiaries offering retail electricity, natural gas service and water service to approximately 4 million customers in Connecticut, Massachusetts, and New Hampshire.
A utility pole is a column or post typically made out of wood used to support overhead power lines and various other public utilities, such as electrical cable, fiber optic cable, and related equipment such as transformers and street lights. It can be referred to as a transmission pole, telephone pole, telecommunication pole, power pole, hydro pole, telegraph pole, or telegraph post, depending on its application. A Stobie pole is a multi-purpose pole made of two steel joists held apart by a slab of concrete in the middle, generally found in South Australia.
The Hartford Electric Light Company (HELCO) is a defunct electrical company that was located on Pearl Street in Hartford, Connecticut. It was merged with the Connecticut Power Company in 1958 and later these became Connecticut Light & Power. Its former corporate headquarters building and main facility are in the Ann Street Historic District.
The Calcutta Electric Supply Corporation (CESC) is the Kolkata-based flagship company of the RP-Sanjiv Goenka Group, born from the erstwhile RPG Group, under the chairmanship of businessman Sanjiv Goenka. It is an Indian electricity generation and the sole distribution company serving 567 square kilometres (219 sq mi) of area administered by the Kolkata municipal corporation, in the city of Kolkata, as well as parts of Howrah, Hooghly, 24 Parganas (North) and 24 Parganas (South) districts in the state of West Bengal. It serves 3.0 million consumers approximately, which includes domestic, industrial and commercial users.
Wyandotte Municipal Services is a not-for-profit service provider located in Wyandotte, Michigan. The services that WMS provides are electric, cable telecommunications, and water supply and treatment to the City of Wyandotte. WMS was created by local residents more than 100 years ago. The City of Wyandotte, Michigan is the only community to own and operate its own power plant, water treatment plant, and cable TV headend.
Electric power transmission, the tools and means of moving electricity far from where it is generated, date back to the late 19th century. They include the movement of electricity in bulk and the delivery of electricity to individual customers ("distribution"). In the beginning, the two terms were used interchangeably.
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:
Easy Energy of Massachusetts, commonly referred to as Easy Energy, is an approved participant in the New England Power Pool and is licensed by the State Department of Public Utilities, Electric Power Division to sell electricity in Massachusetts. The company is headquartered in Bolton, Massachusetts and supplies electricity to residential, industrial and commercial customers in the parts of Massachusetts that fall within National Grid or NSTAR service territory.
Vermont electric power needs are served by over twenty utilities. The largest is Green Mountain Power, a subsidiary of Énergir which recently also took over Central Vermont Public Service. Together this single company represents 70% of the retail customers in Vermont. The state is a small electricity consumer compared with other states. Therefore, its electricity sector has the lowest carbon footprint in the country. As of 2010, the state had the lowest wholesale electricity costs in New England. Efficiency Vermont engages in aggressive initiatives to cut residential electricity waste, which often identifies other problems that it claims can save hundreds per household per year. Accordingly, Vermont's overall energy bills are also relatively lower than in the rest of the New England states.
The provision of electricity in Queensland required a considerable degree of pioneering, innovation, and commitment. Queensland proved to be a pioneer in the supply of electricity in Australia, with the first public demonstration in Australia, the first recorded use for public purposes in the country, the first Parliament House in Australia and the first commercial operations in Australia all occurring in Brisbane.
Electricity Ashburton Limited, trading as EA Networks is a co-operatively-owned electricity distribution company, based in Ashburton, New Zealand.
TBEA Co., Ltd., previously known as Tebian Electric Apparatus, is a Chinese manufacturer of power transformers and other electrical equipment, and a developer of transmission projects. Along with competitors Tianwei Baobian Electric (TWBB) and the XD Group, it is one of the major Chinese manufacturers of transformers.
Coorparoo Substation No. 210 is a heritage-listed electrical substation at 12 Main Avenue, Coorparoo, City of Brisbane, Queensland, Australia. It was designed by Reyburn Jameson and built in 1930 by A. Mason. It is also known as Substation 10. It was added to the Queensland Heritage Register on 1 August 2005.
Wellesley, Massachusetts 
