An uninterruptible power supply (UPS) or uninterruptible power source is a type of continual power system that provides automated backup electric power to a load when the input power source or mains power fails. A UPS differs from a traditional auxiliary/emergency power system or standby generator in that it will provide near-instantaneous protection from input power interruptions by switching to energy stored in battery packs, supercapacitors or flywheels. The on-battery run-times of most UPSs are relatively short but sufficient to "buy time" for initiating a standby power source or properly shutting down the protected equipment. Almost all UPSs also contain integrated surge protection to shield the output appliances from voltage spikes.
A starter is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydraulic. The starter can also be another internal-combustion engine in the case, for instance, of very large engines, or diesel engines in agricultural or excavation applications.
A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a result, power supplies are sometimes referred to as electric power converters. Some power supplies are separate standalone pieces of equipment, while others are built into the load appliances that they power. Examples of the latter include power supplies found in desktop computers and consumer electronics devices. Other functions that power supplies may perform include limiting the current drawn by the load to safe levels, shutting off the current in the event of an [[electrical fhhchcucb ult]], power conditioning to prevent electronic noise or voltage surges on the input from reaching the load, power-factor correction, and storing energy so it can continue to power the load in the event of a temporary interruption in the source power.
A power inverter, inverter, or invertor is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). The resulting AC frequency obtained depends on the particular device employed. Inverters do the opposite of rectifiers which were originally large electromechanical devices converting AC to DC.
Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to as distributed energy resources (DER).
Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy or potential energy into a form that can be either used immediately or stored until needed.
A motor–generator is a device for converting electrical power to another form. Motor–generator sets are used to convert frequency, voltage, or phase of power. They may also be used to isolate electrical loads from the electrical power supply line. Large motor–generators were widely used to convert industrial amounts of power while smaller motor–generators were used to convert battery power to higher DC voltages.
Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inexpensive or when demand is low, and later returned to the grid when demand is high, and electricity prices tend to be higher.
Electric power quality is the degree to which the voltage, frequency, and waveform of a power supply system conform to established specifications. Good power quality can be defined as a steady supply voltage that stays within the prescribed range, steady AC frequency close to the rated value, and smooth voltage curve waveform. In general, it is useful to consider power quality as the compatibility between what comes out of an electric outlet and the load that is plugged into it. The term is used to describe electric power that drives an electrical load and the load's ability to function properly. Without the proper power, an electrical device may malfunction, fail prematurely or not operate at all. There are many ways in which electric power can be of poor quality, and many more causes of such poor quality power.
A battery room is a room that houses batteries for backup or uninterruptible power systems. The rooms are found in telecommunication central offices, and provide standby power for computing equipment in datacenters. Batteries provide direct current (DC) electricity, which may be used directly by some types of equipment, or which may be converted to alternating current (AC) by uninterruptible power supply (UPS) equipment. The batteries may provide power for minutes, hours or days, depending on each system's design, although they are most commonly activated during brief electric utility outages lasting only seconds.
Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the power supplied commands a much higher price per kilowatt hour than base load power. Peak load power plants are dispatched in combination with base load power plants, which supply a dependable and consistent amount of electricity, to meet the minimum demand.
An emergency power system is an independent source of electrical power that supports important electrical systems on loss of normal power supply. A standby power system may include a standby generator, batteries and other apparatus. Emergency power systems are installed to protect life and property from the consequences of loss of primary electric power supply. It is a type of continual power system.
Hybrid vehicle drivetrains transmit power to the driving wheels for hybrid vehicles. A hybrid vehicle has multiple forms of motive power.
A load bank is a piece of electrical test equipment used to simulate an electrical load, to test an electric power source without connecting it to its normal operating load. During testing, adjustment, calibration, or verification procedures, a load bank is connected to the output of a power source, such as an electric generator, battery, servoamplifier or photovoltaic system, in place of its usual load. The load bank presents the source with electrical characteristics similar to its standard operating load, while dissipating the power output that would normally be consumed by it. The power is usually converted to heat by a heavy duty resistor or bank of resistive heating elements in the device, and the heat removed by a forced air or water cooling system. The device usually also includes instruments for metering, load control, and overload protection. Load banks can either be permanently installed at a facility to be connected to a power source when needed, or portable versions can be used for testing power sources such as standby generators and batteries. They are necessary adjuncts to replicate, prove, and verify the real-life demands on critical power systems. They are also used during operation of intermittent renewable power sources such as wind turbines to shed excess power that the electric power grid cannot absorb.
A stand-alone power system, also known as remote area power supply (RAPS), is an off-the-grid electricity system for locations that are not fitted with an electricity distribution system. Typical SAPS include one or more methods of electricity generation, energy storage, and regulation.
A continual power system is a system for reliably supplying uninterrupted power. Examples of a continual power system include uninterruptible power supplies and emergency power systems. The need for continual power systems has risen because more and more essential services depend on consistent power, such as lighting, computing, and communications.
Load management, also known as demand-side management (DSM), is the process of balancing the supply of electricity on the network with the electrical load by adjusting or controlling the load rather than the power station output. This can be achieved by direct intervention of the utility in real time, by the use of frequency sensitive relays triggering the circuit breakers, by time clocks, or by using special tariffs to influence consumer behavior. Load management allows utilities to reduce demand for electricity during peak usage times, which can, in turn, reduce costs by eliminating the need for peaking power plants. In addition, some peaking power plants can take more than an hour to bring on-line which makes load management even more critical should a plant go off-line unexpectedly for example. Load management can also help reduce harmful emissions, since peaking plants or backup generators are often dirtier and less efficient than base load power plants. New load-management technologies are constantly under development — both by private industry and public entities.
Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the flywheel.
Home energy storage devices store electricity locally, for later consumption. Electrochemical energy storage products, also known as "Battery Energy Storage System", at their heart are rechargeable batteries, typically based on lithium-ion or lead-acid controlled by computer with intelligent software to handle charging and discharging cycles. Companies are also developing smaller flow battery technology for home use. As a local energy storage technologies for home use, they are smaller relatives of battery-based grid energy storage and support the concept of distributed generation. When paired with on-site generation, they can virtually eliminate blackouts in an off-the-grid lifestyle.
A mini-grid is an aggregation of electrical loads and one or more energy sources operating as a single system providing electricity and possibly heat, isolated from a main power grid. A modern mini-grid may include renewable- and fossil fuel-based power generation, energy storage, and load control. A mini grid can be fully isolated from the main grid or interconnected to it. If it is interconnected to the main grid, it must also be able to isolate (“island”) from the main grid and continue to serve its customers while operating in an island or autonomous mode. Mini-grids are used as a cost-effective solution for electrifying rural communities where a grid connection is challenging in terms of transmission and cost for the end user population density, with mini-grids often used to electrify rural communities of a hundred or more households that are 10 km or more from the main grid.
