[1] Fig. 1. Diagram of an electrical grid (generation system in red, transmission system in blue, distribution system in green)
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Electrical grid
Electrical grid
[1] An electrical grid/electricity network is an interconnected network for electricity delivery from producers to consumers, comprised of power stations, electrical substations to step voltage up/down, electric power transmission to carry power in long distances, and finally electric power distribution to customers. In that last step, voltage is stepped down again to the needed service voltage. [2] Due to cost of solar panels growing, many explore the potential of other power generation.
interconnect: things connected to to form a system/network in a pattern (like "connect" but more complex);
contrast "to connect": (basically) action of linking 1 thing
[2] Fig. 2.
[2] There are only 4-5 electrical grids that serve all of North America:
The 2 interconnection ones: Western, Eastern, respectively located in West and East of the U.S., specifically;
And the 2 separate ones: In Quebec and Texas.
Alaska also has one.
Structure
Structure
[2] Fig. 3.
A power grid's main parts in order:
Generation (power plants)
Transmission (high-voltage lines)
Distribution (local lines)
[2] Starting with generation, where electricity is generated. The power produced is immediately moved to a generation substation, which uses transformers to increase the voltage for efficient long-distance transmission.
Power plants use generators (wind turbine, hydroelectric generators, steam turbine generators) to convert mechanical energy (from steam, water, or wind) into electricity. All power plants share 1 function: They convert some form of energy and convert it into electrical energy and are built far off populated places for electricity to be efficiently delivered, handled by high-voltage transmission lines. The plant has transformers boosting the voltage to minimize losses within the lines as electricity goes to where it's needed.
mechanical energy: energy an object has due to its motion/position, comprised of 2 main energy types: kinetic energy (movement energy) potential energy (stored energy based on position)
They must be in remote places in order to reduce environmental pollution in densely populated areas, and access natural resources. They need large spaces (to manage large-scale energy production, safely house complex machinery, and handle extensive cooling systems needed to convert heat into electricity), proximity to water for cooling, and proximity to fuel sources (like coal mines) or optimal wind/solar conditions, all of which are rare near cities. Furthermore, radiation of the nuclear power plants are a prominent reason for being installed in a remote location.
[2] Fig. 4. an electric power grid substation, with network of transformers, metal beams, and industrial equipment.
[2] At distribution, electricity is distributed to customers after a step-down transformer steps down electricity to be more safer and practical, done at a substation which also has equipment to regulate electricity quality and breakers to isolate faults. Some energy customers draw power directly from transmission lines, but most are served from feeder lines carrying power from substation, the part referred to as the distribution. From feeders, smaller transformers step down voltage to its final level for industrial/commercical/residential uses prior electricity's final destination.
IO DC flow, most power grids use AC, ~60 Hz in America. AC's major upside is that it's easy to step up/down voltage, which is crucial to send electricity safelly from producer to customer.
[2] Fig. 5. pole-mounted distribution transformer attached to a wooden utility pole
[1] Power stations are often built near energy sources and far off populated areas. Electrical grids vary in size and can cover whole nations/continents. From small to large there are microgrids, wide area synchronous grids, and super grids. Combined transmission and distribution network is part of electricity delivery, called the power grid.
Grids are often synchronous, i.e., all distribution areas operate by 3φ AC frequencies synchronized (so that voltage swings occur at almost the same time). This allows transmission of AC power throughout the area, connecting the electricity generators with consumers. Grids can enable more efficient electricity markets.
Though grids are widespread, as of 2016, 1.4 B ppl global weren't connected to an electrical grid.
Also as electric grids modernize and introduce computer technology, cyber threats start to become a security risk. Particular concerns relate to the more complex computer systems needed to manage grids.
Economics and politics
Economics and politics
[2] We can see a grid as a marketplace: Power producers bring electricity to their market by connecting to the grid and consumers purchase it to use.
Since power grid is a shared resource, organizations must have rules of how each participant in producting, transmittion, consuption can use it.
[2] Fig. 6. A graph depicting AC voltage's graph with its frequency, its voltage peak, and its voltage root mean square.
[2] Fig. 7. A large rotary converter at the Westinghouse Electric & Manufacturing Company works in East Pittsburgh, Pennsylvania.
[2] The 3 overarching technical goals engineers use to design and keep a power grid:
Power quality: Electrical tools assume that power from grid has parameters, mainly that voltage and frequency are stable. Some devices count oscillations in AC grid power to record time, so it's grid frequencies won't deviate. Voltage changes can cause burnouts which damage connected devices. A upside of big power grid is electrical inertia. Their big spinnning gnereators connected give provide momentum smoothing out ripples and spikes that can occur from device faults/fast changing electrical
Reliability: If we take constant power availability for granted, it's by design. Most of grids' complexity is from how we manage faults and provide redundancy to avoid blackouts.
Demand: Since power production and consumption is constant, the a screen's light is a drop of water in turbine or breeze across a windmill microseconds ago. Load following is a power plant/energy source's ability to adjust electricity output up/down to match fluctuating demand on power grids. Electrical demand follows a pattern, but are affected by extreme weathers. Grid operators balance demand by dispatching generation capacity in real time.
[2] Fig. 8. A graph depicting of time with respect to the magnitude of electricity demand total.
The cheapest power sources are used to fufill the more consistent base load and higher cost sources, used to peak if demand exceeds the base.
Smart grid
Smart grid
[1.2] A smart grid is a modern enhanced electrical grid, using 2-way communications and distributed intelligent devices. Due to all issues electrical grids face, a smart's grid's softwares and devices that can communicate amongst, to help us process huge amouts of data to decide how to manage a grid, and helping with demands. Customers are oblivious to how much energy is used; Smart grids can remove the obfuscation for better decisions.
Types
Types
Grouped by size
Grouped by size
References
References
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