Electrical grid
Also as electric grids modernize and introduce computer technology, cyber threats start to become a security risk.
Neighbouring interconnections with the same frequency and standards can be synchronized and directly connected to form a larger interconnection, or they may share power without synchronization 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.
For example, in 2018, Kosovo used more power than it generated due to a dispute with Serbia, leading to the phase across the whole synchronous grid of Continental Europe lagging behind what it should have been.
[17] A super grid or supergrid is a wide-area transmission network that is intended to make possible the trade of high volumes of electricity across great distances.
Super grids typically use high-voltage direct current (HVDC) to transmit electricity long distances.
[31] In cities and towns of North America, the grid tends to follow the classic radially fed design.
As the distance from the substation grows, the fanout continues as smaller laterals spread out to cover areas missed by the feeders.
Two alternatives to grid storage are the use of peaking power plants to fill in supply gaps and demand response to shift load to other times.
However, if the demand of electricity exceed the capacity of a local power grid, it will cause safety issue like burning out.
Although the speed is kept largely constant, small deviations from the nominal system frequency are very important in regulating individual generators and are used as a way of assessing the equilibrium of the grid as a whole.
Conversely, when the grid is heavily loaded, the frequency naturally slows, and governors adjust their generators so that more power is output (droop speed control).
In addition, there's often central control, which can change the parameters of the AGC systems over timescales of a minute or longer to further adjust the regional network flows and the operating frequency of the grid.
For timekeeping purposes, the nominal frequency will be allowed to vary in the short term, but is adjusted to prevent line-operated clocks from gaining or losing significant time over the course of a whole 24 hour period.
Typically, some generators are kept running at lower output powers (spinning reserve) to deal with failures as well as variation in demand.
In addition generators can be off-line for maintenance or other reasons, such as availability of energy inputs (fuel, water, wind, sun etc.)
Most grid codes specify that the load is shared between the generators in merit order according to their marginal cost (i.e. cheapest first) and sometimes their environmental impact.
A voltage reduction may be an effect of disruption of an electrical grid, or may occasionally be imposed in an effort to reduce load and prevent a power outage, known as a blackout.
Certain types of combustion turbine can be configured for black start, providing another option in places without suitable hydroelectric plants.
[37] In 2017 a utility in Southern California has successfully demonstrated the use of a battery energy storage system to provide a black start, firing up a combined cycle gas turbine from an idle state.
Contributing factors include: Demand response is a grid management technique where retail or wholesale customers are requested or incentivised either electronically or manually to reduce their load.
Currently, transmission grid operators use demand response to request load reduction from major energy users such as industrial plants.
[42] Electronic power conditioning and control of the production and distribution of electricity are important aspects of the smart grid.
Numerous contributions to the overall improvement of energy infrastructure efficiency are anticipated from the deployment of smart grid technology, in particular including demand-side management.
Smart grids could also monitor/control residential devices that are noncritical during periods of peak power consumption, and return their function during nonpeak hours.
Roll-out of smart grid technology also implies a fundamental re-engineering of the electricity services industry, although typical usage of the term is focused on the technical infrastructure.
Coal gas was first produced on customer's premises but later evolved into gasification plants that enjoyed economies of scale.
But gas lamps produced poor light, wasted heat, made rooms hot and smoky, and gave off hydrogen and carbon monoxide.
[59] Merz was appointed head of a parliamentary committee and his findings led to the Williamson Report of 1918, which in turn created the Electricity (Supply) Act 1919.
No longer were electric utilities built as vertical monopolies, where generation, transmission and distribution were handled by a single company.
[67] In the current railway electrification system of China, State Grid Corporation of China—Archived 2021-12-21 at the Wayback Machine—is an important power supplier.
