Electrical grid

General layout of electricity networks. Voltages and depictions of electrical lines are typical for Germany and other European systems.
Turbo generator
Diagram of an electric power system, generation system in red
500 kV Three-phase electric power Transmission Lines at Grand Coulee Dam; four circuits are shown; two additional circuits are obscured by trees on the right; the entire 7079 MW generation capacity of the dam is accommodated by these six circuits.
Network diagram of a high voltage transmission system, showing the interconnection between the different voltage levels. This diagram depicts the electrical structure of the network, rather than its physical geography.
Simplified electrical grid with energy storage
Simplified grid energy flow with and without idealized energy storage for the course of one day
A brownout near Tokyo Tower in Tokyo, Japan
Toronto during the Northeast blackout of 2003, which required black-starting of generating stations.
One conceptual plan of a super grid linking renewable sources across North Africa, the Middle East and Europe. (DESERTEC)
The synchronous grids of Europe
The two major and three minor interconnections of North America
Major WASGs around the world

Interconnected network for electricity delivery from producers to consumers.

- Electrical grid
General layout of electricity networks. Voltages and depictions of electrical lines are typical for Germany and other European systems.

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Five-hundred kilovolt (500 kV) Three-phase electric power Transmission Lines at Grand Coulee Dam; four circuits are shown; two additional circuits are obscured by trees on the far right; the entire 7079 MW nameplate generation capacity of the dam is accommodated by these six circuits.

Electric power transmission

Bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation.

Bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation.

Five-hundred kilovolt (500 kV) Three-phase electric power Transmission Lines at Grand Coulee Dam; four circuits are shown; two additional circuits are obscured by trees on the far right; the entire 7079 MW nameplate generation capacity of the dam is accommodated by these six circuits.
Diagram of an electric power system; transmission system is in blue
Five-hundred kilovolt (500 kV) three-phase transmission tower in Washington State, line is "Bundled" 3-ways
Three abreast Electrical Pylons in Webster, Texas
New York City streets in 1890. Besides telegraph lines, multiple electric lines were required for each class of device requiring different voltages
Working for Westinghouse, William Stanley Jr. spent his time recovering from illness in Great Barrington installing what is considered the world's first practical AC transformer system.
Westinghouse alternating current polyphase generators on display at the 1893 World's Fair in Chicago, part of their "Tesla Poly-phase System". Such polyphase innovations revolutionized transmission
A transmission substation decreases the voltage of incoming electricity, allowing it to connect from long-distance high voltage transmission, to local lower voltage distribution. It also reroutes power to other transmission lines that serve local markets. This is the PacifiCorp Hale Substation, Orem, Utah, USA
The synchronous grids of Europe
A high-power electrical transmission tower, 230 kV, double-circuit, also double-bundled
A 115 kV subtransmission line in the Philippines, along with 20 kV distribution lines and a street light, all mounted in a wood subtransmission pole
115 kV H-frame transmission tower
Electrical grid without a transformer.
Electrical grid with a transformer.
"Black box" model for transmission line
Voltage on sending and receiving ends for lossless line
High voltage pylons carrying additional optical fibre cable in Kenya

The combined transmission and distribution network is part of electricity delivery, known as the electrical grid.

A 50 kVA pole-mounted distribution transformer

Electric power distribution

Final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers.

Final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers.

A 50 kVA pole-mounted distribution transformer
General layout of electricity networks. The voltages and loadings are typical of a European network.
The late 1870s and early 1880s saw the introduction of arc lamp lighting used outdoors or in large indoor spaces such as this Brush Electric Company system installed in 1880 in New York City.
Substation near Yellowknife, in the Northwest Territories of Canada
High voltage power pole in rural Butte County, California
World map of mains voltage and frequencies
Japan's utility frequencies are 50 Hz and 60 Hz.

Circuit breakers and switches enable the substation to be disconnected from the transmission grid or for distribution lines to be disconnected.

Electric power is transmitted on overhead lines like these, and also on underground high-voltage cables

Electric utility

Company in the electric power industry that engages in electricity generation and distribution of electricity for sale generally in a regulated market.

Company in the electric power industry that engages in electricity generation and distribution of electricity for sale generally in a regulated market.

Electric power is transmitted on overhead lines like these, and also on underground high-voltage cables

Electric utilities are facing increasing demands including aging infrastructure, reliability, and regulation.

Electric power is transmitted by overhead lines like these, and also through underground high-voltage cables.

Electric power

Rate, per unit time, at which electrical energy is transferred by an electric circuit.

Rate, per unit time, at which electrical energy is transferred by an electric circuit.

Electric power is transmitted by overhead lines like these, and also through underground high-voltage cables.
Animation showing power source
Animation showing electric load
Transmission of power through an electric circuit

It is usually supplied to businesses and homes (as domestic mains electricity) by the electric power industry through an electric power grid.

The blinking of non-incandescent city lights is shown in this motion-blurred long exposure. The AC nature of the mains power is revealed by the dashed appearance of the traces of moving lights.

AC power

Electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit.

Electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit.

The blinking of non-incandescent city lights is shown in this motion-blurred long exposure. The AC nature of the mains power is revealed by the dashed appearance of the traces of moving lights.
Instantaneous power in AC systems when the current lags behind the voltage by 50 degrees.

It does, however, serve an important function in electrical grids and its lack has been cited as a significant factor in the Northeast Blackout of 2003.

Three-phase transformer with four wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases

Three-phase electric power

Common type of alternating current used in electricity generation, transmission, and distribution.

Common type of alternating current used in electricity generation, transmission, and distribution.

Three-phase transformer with four wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases
The first AC motor developed by Italian physicist Galileo Ferraris. This was a two-phase motor and required four wires.
Normalized waveforms of the instantaneous voltages in a three-phase system in one cycle with time increasing to the right. The phase order is 1‑2‑3. This cycle repeats with the frequency of the power system. Ideally, each phase's voltage, current, and power is offset from the others’ by 120°.
Three-phase electric power transmission lines
Three-phase transformer (Békéscsaba, Hungary): on the left are the primary wires and on the right are the secondary wires
Animation of three-phase current
Wye (Y) and delta (Δ) circuits
A delta-wye configuration across a transformer core (note that a practical transformer would usually have a different number of turns on each side).
A transformer for a "high-leg delta" system used for mixed single-phase and three-phase loads on the same distribution system. Three-phase loads such as motors connect to L1, L2, and L3. Single-phase loads would be connected between L1 or L2 and neutral, or between L1 and L2. The L3 phase is 1.73 times the L1 or L2 voltage to neutral so this leg is not used for single-phase loads.
Three-phase AC generator connected as a wye or star source to a wye or star connected load
Three-phase AC generator connected as a wye source to a delta-connected load
Three-phase electric machine with rotating magnetic fields
Three phase plug used in the past on electric stoves in Germany

It is a type of polyphase system employing three wires (or four including an optional neutral return wire) and is the most common method used by electrical grids worldwide to transfer power.

U.S. NRC image of a modern steam turbine generator (STG).

Electric generator

Device that converts motive power into electric power for use in an external circuit.

Device that converts motive power into electric power for use in an external circuit.

U.S. NRC image of a modern steam turbine generator (STG).
Early Ganz Generator in Zwevegem, West Flanders, Belgium
The Faraday disk was the first electric generator. The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m, through the external circuit, and back into the center of the disk through the axle.
Hippolyte Pixii's dynamo. The commutator is located on the shaft below the spinning magnet.
This large belt-driven high-current dynamo produced 310 amperes at 7 volts. Dynamos are no longer used due to the size and complexity of the commutator needed for high power applications.
Ferranti alternating current generator, c. 1900.
A small early 1900s 75 kVA direct-driven power station AC alternator, with a separate belt-driven exciter generator.
The Athlone Power Station in Cape Town, South Africa
Hydroelectric power station at Gabčíkovo Dam, Slovakia
Hydroelectric power station at Glen Canyon Dam, Page, Arizona
Mobile electric generator
Protesters at Occupy Wall Street using bicycles connected to a motor and one-way diode to charge batteries for their electronics

Generators provide nearly all of the power for electric power grids.

A table lamp connected to a wall socket (the mains)

Mains electricity

[[File:Access to Electricity.svg|thumb|upright=1.4|World map showing the percentage of the population in each country with access to mains electricity (as of 2017), a measure of the extent of electrification.

[[File:Access to Electricity.svg|thumb|upright=1.4|World map showing the percentage of the population in each country with access to mains electricity (as of 2017), a measure of the extent of electrification.

A table lamp connected to a wall socket (the mains)
World map of mains voltages and frequencies, simplified to country level
A 50 Hz ±5 Hz vibrating-reed mains frequency meter for 220 V

It is the form of electrical power that is delivered to homes and businesses through the electric grid in many parts of the world.

Pole-mounted distribution transformer with center-tapped secondary winding used to provide "split-phase" power for residential and light commercial service, which in North America is typically rated 120/240 V.

Transformer

Passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits.

Passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits.

Pole-mounted distribution transformer with center-tapped secondary winding used to provide "split-phase" power for residential and light commercial service, which in North America is typically rated 120/240 V.
Ideal transformer connected with source VP on primary and load impedance ZL on secondary, where 0 < ZL < ∞.
Ideal transformer and induction law
Leakage flux of a transformer
Real transformer equivalent circuit
Instrument transformer, with polarity dot and X1 markings on low-voltage ("LV") side terminal
Power transformer overexcitation condition caused by decreased frequency; flux (green), iron core's magnetic characteristics (red) and magnetizing current (blue).
Laminated core transformer showing edge of laminations at top of photo
Interleaved E-I transformer laminations showing air gap and flux paths
Laminating the core greatly reduces eddy-current losses
Small toroidal core transformer
Windings are usually arranged concentrically to minimize flux leakage.
Cut view through transformer windings.
Legend: 
White: Air, liquid or other insulating medium 
Green spiral: Grain oriented silicon steel 
Black: Primary winding 
Red: Secondary winding
Cutaway view of liquid-immersed transformer. The conservator (reservoir) at top provides liquid-to-atmosphere isolation as coolant level and temperature changes. The walls and fins provide required heat dissipation.
Substation transformer undergoing testing.
An electrical substation in Melbourne, Australia
showing three of five 220 kV – 66 kV transformers, each with a capacity of 150 MVA
Camouflaged transformer in Langley City
Transformer at the Limestone Generating Station in Manitoba, Canada
Schematic of a large oil-filled power transformer 1. Tank 2. Lid
3. Conservator tank 4. Oil level indicator 5. Buchholz relay for detecting gas bubbles after an internal fault 6. Piping
7. Tap changer 8. Drive motor for tap changer 9. Drive shaft for tap changer
10. High voltage (HV) bushing
11. High voltage bushing current transformers
12. Low voltage (LV) bushing
13. Low voltage current transformers
14. Bushing voltage-transformer for metering
15. Core 16. Yoke of the core
17. Limbs connect the yokes and hold them up 18. Coils
19. Internal wiring between coils and tapchanger
20. Oil release valve
21. Vacuum valve
Faraday's experiment with induction between coils of wire
Induction coil, 1900, Bremerhaven, Germany
Faraday's ring transformer
Shell form transformer. Sketch used by Uppenborn to describe ZBD engineers' 1885 patents and earliest articles.
Core form, front; shell form, back. Earliest specimens of ZBD-designed high-efficiency constant-potential transformers manufactured at the Ganz factory in 1885.
The ZBD team consisted of Károly Zipernowsky, Ottó Bláthy and Miksa Déri
Stanley's 1886 design for adjustable gap open-core induction coils
"E" shaped plates for transformer cores developed by Westinghouse

Transformers range in size from RF transformers less than a cubic centimeter in volume, to units weighing hundreds of tons used to interconnect the power grid.

Wind farm in Xinjiang, China

Wind power

Mostly the use of wind turbines to generate electricity.

Mostly the use of wind turbines to generate electricity.

Wind farm in Xinjiang, China
Electricity production by source
Global map of wind speed at 100 m above surface level.
Roscoe Wind Farm in West Texas
Distribution of wind speed (red) and energy (blue) for all of 2002 at the Lee Ranch facility in Colorado. The histogram shows measured data, while the curve is the Rayleigh model distribution for the same average wind speed.
The world's second full-scale floating wind turbine (and first to be installed without the use of heavy-lift vessels), WindFloat, operating at rated capacity (2 MW) approximately 5 km offshore of Póvoa de Varzim, Portugal
Wind energy generation by region over time
Wind generation by country
Share of electricity production from wind, 2020
Wind turbines are typically installed in windy locations. In the image, wind power generators in Spain, near an Osborne bull.
Seasonal cycle of capacity factors for wind and photovoltaics in Europe under idealized assumptions. The figure illustrates the balancing effects of wind and solar energy at the seasonal scale (Kaspar et al., 2019).
Onshore wind cost per kilowatt-hour between 1983 and 2017
A turbine blade convoy passing through Edenfield in the U.K. (2008). Even longer 2-piece blades are now manufactured, and then assembled on-site to reduce difficulties in transportation.
A small Quietrevolution QR5 Gorlov type vertical axis wind turbine on the roof of Colston Hall in Bristol, England. Measuring 3 m in diameter and 5 m high, it has a nameplate rating of 6.5 kW.
Livestock grazing near a wind turbine.
Part of the Seto Hill Windfarm in Japan.
Wind turbines such as these, in Cumbria, England, have been opposed for a number of reasons, including aesthetics, by some sectors of the population.
A panoramic view of the United Kingdom's Whitelee Wind Farm with Lochgoin Reservoir in the foreground.
Charles F. Brush's windmill of 1888, used for generating electric power.

Wind farms consist of many individual wind turbines, which are connected to the electric power transmission network.