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Actuator: In electrical engineering, the term actuator refers to a mechanism that causes a device to be turned on or off, adjusted or moved, usually in response to an electrical signal. In some literature the terms actor or effector are also used. The term “effector” is preferred by programmers, whereas engineers tend to favor “actuator.” An example of an actuator is a motor that closes blinds in response to a signal from a sunlight detector. Actuators enable computers to control complex manufacturing processes without human intervention or supervision.
Advanced process control (APC): In general terms, advanced process control refers to large-scale computer systems that are used to monitor and control processing plants such as cement factories or oil refineries. The systems extend traditional process control, which is used to monitor and control individual processes, by evaluating and controlling multiple processes across the plant. By monitoring multiple processes, APC systems can optimize operations for multiple parameters, evaluating the impact each adjustment will have on neighboring operations by referencing current and historical data. With a broad yet detailed view of an entire plant’s operations, APC applications allow processes to operate closer to their maximum capacity, while maintaining the necessary standards of reliability and safety.
Air-insulated switchgear: see Switchgear.
Algorithm: A set of (mathematical) instructions or procedures for carrying out a specific task such as defining the steps taken by an automation system.
Alternating current (AC): Alternating current is a form of electricity in which the current alternates in direction (and the voltage alternates in polarity) at a frequency defined by the generator (usually between 50 and 60 times per second, ie, 50 - 60 hertz). AC was adopted for power transmission in the early days of electricity supply because it had two major advantages over direct current (DC): its voltage could be stepped up or down according to need using transformers (see Transformer), and it could be interrupted more easily than DC. Neither advantage is as relevant today as it once was because power electronics can solve both issues for DC. (See also Direct current and Transmission and distribution.)
Alternator: see Generator.
Ampere: The standard unit of electrical current.
(See also Current.)
Arc flash: An arc flash is caused by current flowing between two conducting surfaces and most commonly occurs in switchgear as a result of faulty equipment or poor work practices. Left unchecked, arc flashes release a tremendous amount of energy in a high-pressure blast of heat and debris, which can result in serious injuries to workers and damage to equipment.
Arc welding: A group of welding procedures that fuse metal pieces by melting them together, using heat from an electric arc between an electrode and the work piece. The arc is caused by electrical current flowing though plasma consisting of ionized air molecules and metal ions. Material from the electrode is transferred to the work piece, and the electrode is consumed over time. Arc-welding processes are attractive because of their low capital and running costs.
Arc-welding cell: The area of a factory set up to weld metals using electric arcs. ABB provides modular robotic arc-welding cells that are ready to install in a customer’s plant.
Asset management: Also referred to as industrial and plant asset management. Asset management systems collect and manage data on the condition and availability of major plant equipment in discrete and process manufacturing plants. This enables plant operators to plan maintenance schedules more effectively (condition-based maintenance), avoiding both unnecessary equipment inspections and unexpected breakdowns, which can cause expensive interruptions in production time. Computerized asset management systems gather data in real-time to ensure maximum production uptime and throughput, with a minimum of human interaction.
Asynchronous machines: See Machines
Azipod: The registered trademark of a family of modular electric propulsion systems for ships, the first of which was co-developed by ABB in the 1980s. The Azipod unit is fitted to the ship’s hull externally in a pod, or casing, and combines the functions of a propulsion motor, main propeller, rudder and stern thruster. Since these functions are no longer installed as separate units inside the ship, space onboard can be used for other purposes. Azipod units also contribute to improved hydrodynamics, which result in fuel savings of around 15 percent compared to conventional propulsion systems.
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Back-to-back connection: In HVDC terms, links used to connect neighboring grids are often referred to as “back-to-back” connections, indicating that the distance between the two grids is minimal. Such connections are able to link independent power grids, including those operating at different frequencies, and enable power to flow from one grid to another. This means that generators on either grid can be used to secure the supply of electricity across the extended network. The connections can also improve voltage and frequency stability in the linked grids.
Note: The term “back-to-back connection” is also used to describe a test set-up for electrical devices where a motor and a generator are connected to the same shaft line.
Bandwidth: 1. In computing, bandwidth is often a synonym for the rate of information transmitted by a network connection or interface. For example, a modem’s bandwidth might be described as 56K, which means it is capable of transmitting 56,000 “bits” of information per second. A bit is the smallest unit of computerized data, comprising a single binary digit (ie, 1 or 0). 2. Bandwidth in electronic communication is the difference between the highest- and the lowest-frequency signal in a given transmission medium. It is measured in hertz (Hz).
Barge: In the oil and gas industry, a barge is an unpowered multipurpose marine vessel. Barges are used as cargo tankers, equipment and supply carriers, crane platforms and support and accommodation bases in offshore drilling, and as submarine pipe-laying vessels.
Base-load power plant: To maintain power supplies as efficiently as possible, some power stations run near to full capacity all the time, while others are brought online or increase production temporarily to meet transient peaks in demand for electricity. The plants that maintain constant levels of production tend to be those that rely on lower-cost fuels and are known as “base-load” power plants.
Biofuel: Fuel derived from biomass, ie, (recently) living organisms. This does not include fossil fuels such as coal and oil, which are derived from ancient organisms. Bioethanol, a fuel derived from sugar cane, corn and similar materials is an example of a biofuel. (See also Carbon cycle.)
Blackout: A complete loss of power resulting from damage or equipment failure in a power station, power lines or other parts of the power system. A blackout may also be referred to as a power outage or power failure. (See High-current transients, Reactive power, Wide-Area Monitoring Systems.)
Black-start capability: The ability of a power system (a generator or grid subsection) to restart after a blackout, independently of the larger grid, by using local generators. For example, HVDC Light transmission systems can be fitted with small diesel generators to provide auxiliary power that can be operational almost immediately in the event of a blackout. This power enables voltage control to be established and normal operations to be resumed quickly.
Brownout: A dip in the voltage level of a power system, which can damage electrical equipment or cause it to under perform, eg, lights dim. (See Voltage drop.)
Busbar: An electrical conductor that makes a common connection between several circuits. Sometimes, electrical wire cannot accommodate high-current applications, and electricity must be conducted using a more substantial busbar — a thick bar of solid metal (usually copper or aluminum). Busbars are uninsulated, but are physically supported by insulators. They are used in electrical substations to connect incoming and outgoing transmission lines and transformers; in a power plant to connect the generator and the main transformers; in industry, to feed large amounts of electricity to equipment used in the aluminum smelting process, for example, or to distribute electricity in large buildings
Bushing: A bushing is a cyclindrical insulating component, usually made of ceramic, that houses a conductor. It enables a conductor to pass through a grounded enclosure, such as a transformer tank (the physical shell of a transformer), a wall or other physical barrier, to connect electrical installations. In the case of a transformer, bushings protect the conductors that connect a transformer’s core to the power system it serves through channels in the transformer’s housing.
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Capacitance: The ability of a device to store an electrical charge (electrical charge is what flows in electric current). Capacitance is used in many different applications. (See Capacitor.)
The unit of capacitance is the Farad, though it can also be referred to in Coulombs per volt (Coulomb being the standard unit of electrical charge). The Farad is a very large unit and capacitances are usually on the order of microfarads, µF (1 µF = 10-6 F) and picofarads, abbreviated pF
(1 pF = 10-12 F).
Capacitor (also referred to as a condenser): A multi-purpose device that can store electrical charge in the form of an electric field. It is used, for example, for power factor correction in (inductive) AC circuits. Capacitors are used to buffer electricity (smooth out peaks) and to guard against momentary voltage losses in circuits (when changing batteries, for example). (See also Capacitance.)
Capacitor bank: A number of capacitors connected in parallel. (See also Parallel.)
Carbon cycle: The circulation of carbon through its various forms in the environment. Briefly, carbon dioxide in the atmosphere is fixed (ie, converted into solid matter) by the process of photosynthesis in plants and green algae. These then die and rot under the influence of bacteria and fungi or are consumed by higher organisms in the form of food or fuel (burning plant matter or fossil fuels). Either way, carbon is released into the atmosphere as carbon dioxide and is available again for fixation (ie, incorporation into biomass).
Cascading power failure: A cascade happens when a part of the power grid fails, and shifts its power load to other elements in the grid. Overloaded, these elements also begin to shut down and shift their power load onto other elements, and so on. The resulting surge current can induce ongoing failures and take down an entire power system in a very short time, “cascading” through parts and systems like a ripple on a pond until the grid collapses.
Charging station: An installation at which an electric vehicle can be plugged into the grid to charge its battery. There are several types of charging station, including low-voltage, lower current installations that charge a battery over a period of several hours (for use in homes, for example), and higher-voltage, higher current fast-charging stations for a more rapid service in public places (car parks, public buildings, etc.).
CHP: Combined heat and power, an acronym for the co-generation of heat and power. (See Co-generation.)
Circuit breaker: Devices that interrupt high currents to protect electrical equipment from damage caused by current surges, eg, from a short circuit or a lightning strike. (On a much smaller scale, they are used as an alternative to fuses in the home.)
Circuit breakers are typically classified according to the medium they use to inhibit arc formation between the open contacts of the breaker. Media used include air, sulfur hexafluoride gas, oil and a vacuum.
Closed Control System (CCS): This is a system used to regulate a process using feedback control (as opposed to an open control system, which relies on feed forward control). A closed system responds to actual system conditions with a range of responses. It is slower to react to changes in process conditions than an open system, but it is more specific in its responses and is able to deal with a broader range of conditions. An example of closed loop control is a driver steering a car. If the car veers to the left, the driver steers right to compensate.
Co-generation: A particularly efficient method of electricity generation that diverts heat, produced as a by-product of the power generation process, to domestic and industrial heating systems. The heat is produced by combustion of fuel in the power station to create the steam that drives the generating turbines. It would otherwise be released to the atmosphere.
Collaborative production management (CPM): A method of unifying disparate yet interdependent production systems in order to optimize productivity. Computerized CPM solutions are software applications that enable process manufacturers to plan, track, analyze and direct their operations.
Combined-cycle power plant: conventional thermal power stations produce steam to drive turbines that generate electricity. In a combined cycle plant, two turbines are used. The first is driven by oil or gas, and waste heat from that process contributes to the production of steam to drive the second turbine
Combiners: Also called junction box or combiner box. Through this combiner, individual DC circuits from photovoltaic modules are combined into a single output. A combiner might include disconnect devices, overcurrent devices and remote monitoring devices.
Compression train: In the oil and gas industry, the compression train is the entire line of equipment that contributes to process of compressing gas: It includes valves, scrubbers, coolers and recycling loops.
Conductor: An electrical conductor is any substance through which electrical current can flow. Since electrical current is a process involving the flow of electrons, how well a material conducts electricity depends on its atomic structure and chemical consistency.
Conductivity also depends on how strong the bond is between electrons and the metallic ions with which they are associated. The weaker the bond, the better the conductor. All metals are conductors (copper is a particularly good one). Plastics are not good conductors, but make good insulators. Semi-conductors are materials whose ability to conduct electricity can be controlled.
Super-conductors, under special conditions, offer no electrical resistance, so electricity can flow indefinitely. More generally, a conductor refers to a material that can transmit electricity, heat or sound.
Concentrating solar power (CSP): CSP is a technology that makes use of precisely oriented mirrors to concentrate sunlight onto receivers that convert the sun's radiation into heat. The heat generated is used to produce steam, which runs a steam turbine, or powers a heat engine driving a generator. The thermal energy can also be stored in order to produce electricity at a later time.
Concentrating photovoltaics (CPV): CPV is a technology that makes use of precisely oriented lenses or mirrors to concentrate the sun's radiation onto photovoltaic cells and produce electricity.
Converter: An electrical device, comprising a rectifier and inverter, used to alter the voltage and frequency of incoming alternating current in an electrical system. The term may also refer to inverters, rectifiers or frequency converters. (See also Converter station, Inverter, Rectifier, Frequency converter).
Converter station: Special equipment is needed to convert electricity from alternating current (AC) to direct current (DC), or vice versa. High-voltage DC (HVDC) converter stations use power electronic devices called thyristors to make these conversions. (See also HVDC and HVDC Light.)
Coupling transformer: A coupling transformer is a device that permits two (usually) separate circuits to influence one another. Such a setup can be desirable for control purposes. It can also be used, for example, to inject high frequency signals into power lines for communications purposes.
Current: The rate at which electrons flow through a circuit is defined as the current. If an electric circuit is likened to water flowing through a system of pipes, the current is analogous to the rate at which the water is flowing. Electric current is measured in amps.
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DC grid: Today’s electrical transmission systems are almost exclusively based on alternating current (AC), but the development of high-voltage, direct current (DC) technology has made it possible to build a DC grid (DC transmission network) that can handle bulk power flows over long distances. Power from such DC grids can be fed into the AC networks as needed. Overlay DC grids would handle fluctuations and instability in the network better than AC systems and are a part of the “smart grid” concept (see also Smart grid).
Demand-response: The term demand-response refers to a variety of technologies required to make demand for electricity more responsive to the supply available. As utilities generate more electricity from intermittent sources of energy such as wind and solar, demand-response technologies are needed to help consumers use power when it is plentiful and reduce their consumption when there is less available.
Direct current (DC): This is electrical current that does not alternate (see Alternating current), the electrons flow through the circuit in one direction. As a result, DC does not generate reactive power (see Reactive Power). This means that, in a DC system, only real (or active) power is transmitted, making better use of the system’s capacity. In order to transmit electrical power as DC, the alternating current generated in the power plant must be converted into DC. At the other end of the process, the DC power must be converted back into AC, and fed into the AC-transmission or distribution network. The transmission of DC current has very low losses. In the conversion between the two forms of power, known as rectification, incurs additional power losses and so it is worth while only when these losses are less than would be incurred by AC transmission, ie, over very long distances (~1000 km for overhead lines, ~100 km for underwater). The other situation in which DC transmission is advantageous is when connecting asynchronous grids, ie, where adjoining electricity grids have different frequencies (eg, 50 or 60 Hz, as happens in some parts of Brazil and the United States). (See HVDC.)
Direct normal irradiance (DNI): DNI is the amount of radiation per surface area received from the sun and a narrow annulus of sky around it that strikes a surface that always faces the sun's radiation.
Direct torque control: A drive system (see Drive) that controls the speed of an electric motor, and hence the torque it can produce on a rotating shaft. The drive works by regulating the amount of power the motor draws from the grid. Torque is an angular force that causes rotation, as seen for example in a car’s engine, which turns the vehicle’s drive shaft.
Disaster Recovery - As related to IT or technology systems that support critical business functions, Disaster Recovery (DR) is the combination of technology, processes, policies and procedures used to prepare for the continuity and recovery of critical infrastructure and/or applications that may otherwise be interrupted by natural or human induced disasters. In SCADA systems, Disaster Recovery is typically deployed using a secondary set of backup servers, installed in a location that is physically separated from the primary server set. The backup servers actively monitor the primary's operations and data processing, in a "warm standby" mode, allowing for fast fail-over in the event of an interruption of service at the primary location. In addition to the backup DR servers providing a system sustainability function, once re-established, the primary servers can retrieve their missing data from the backup servers, ensuring data integrity across both sets of DR servers.
Distributed control system (DCS): A control system that regulates a process (manufacturing, chemical or other) from a series of strategic positions in the processing plant, as opposed to from a single, centralized control unit.
Microprocessor-based distributed control systems (DCS) originated in continous process industries (eg, refineries). and integrate distributed automation controllers, networks, application servers, workstations and other modules necessary to build a complete automation system.
Distributed generation: This term refers to electricity generating installations that are scattered across the grid, rather than placed at a central location. They tend to be small-scale generating plants – often operating using renewable fuels. They also include domestic power generators such as roof-top wind turbines and solar panels, and microhydro installations. As more smart technologies are incorporated into the grid, enabling local distribution grids to receive as well as deliver electricity, distributed generation will become an increasingly common feature of our power systems.
Distribution substation: A distribution substation comprises medium-voltage switchgear, transformers and low-voltage distribution equipment. It is used to transfer power from a medium-voltage electricity distribution system to a low-voltage distribution system that serves groups of domestic or industrial consumers.
Distribution transformers: Distribution transformers are used to regulate the supply of power to residential premises, factories and elsewhere. (See also Transformer.)
District heating: a district heating system is one that makes use of heat generated at a central location, often in a thermal power plant, to heat water that is then fed through a communal system, delivering heat to homes in the surrounding area.
Downstream: The oil industry term “downstream” refers to all petroleum activities from the processing of refining crude oil into petroleum products to the distribution, marketing, and shipping of those products. See also Upstream.
Drive: A drive is an electronic device used to regulate the performance of an electric motor. It works by controlling the power, frequency and current the motor draws from the grid. Drives (also referred to as a variable-speed motor drive) can lead to considerable energy savings as most motors are fixed-speed devices that run at full speed, even when a lower speed would suffice. Many motors are controlled by “throttling down,” which is equivalent to slowing a car by using the brake, rather than taking your foot off the accelerator, and does not save energy. Reducing a motor’s speed by half using a drive can reduce the energy it consumes to one-eighth of its consumption at full speed.
Dynamic shunt compensation: A technology used to stabilize voltage by introducing or absorbing reactive power at specific points of a power transmission grid. The system helps to improve power transmission capacity as well as the overall stability of the grid. Dynamic shunt compensation is one of the three main FACTS (Flexible Alternating Current Transmission Systems) technologies, the others being series compensation and dynamic energy storage. (See also Series and Shunt.)
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Eco-efficiency: Combining efficiency and ecological aspects in the pursuit of sustainable development.
Energy Resources Conservation Board see ERCB Directive 17
Electric motor: A device that converts electrical energy into mechanical energy that can be used to drive mechanical equipment.
Electrical balance of plant (EBoP): The sum of all electrical equipment required for safe and coordinated operation of various parts of a power plant.
Electrical drivetrain: In the wind power industry, this term refers to the combination of the a wind turbine’s generator, converter and transformer.
Watt = Ampere x Volt
1,000 A = 1 Kiloampere (=kA)
1,000 V = 1 Kilovolt (= kV)
1,000 W = 1 Kilowatt (= kW)
1,000,000 W = 1,000 kW = 1Megawatt (= MW)
In a home the voltage in the outlets is normally 220 or 110 Volt.
Large power transmission lines have voltages in the range of 220 - 800 kV.
A typical incandescent (not fluorescent) light bulb consumes 40 - 100 Watt.
A normal home in North America or Europe consumes power in the range of 1 - 10 kW.
A large wind power unit can generate 3,000 kW (= 3 MW)
A large coal or nuclear power station can generate 500 - 4,000 MW. (Individual nuclear generating units have a capacity of 1 - 1.3 GW).
Electricity is difficult to store. The most effective way to store surplus electricity in terms of cost and environmental impact is to use it to pump water uphill into the reservoirs of hydropower plants, a process known as pumped storage. Alternatives include large-scale batteries.
All stationary charged particles are surrounded by an electric field (measured in volts/meter). Charged particles in motion (eg, electrons in an electrical current) are also surrounded by a magnetic field (measured in amps/meter). The combination of an electric field (around the charged particles) and the magnetic field (generated when the charged particles flow) is known as an electromagnetic field (sometimes abbreviated to EMF). Radio waves are a form of electromagnetic radiation. Note: the terms “electric field” and “magnetic field” are not interchangeable.
The release or discharge of substances, effluents or pollutants into the environment.
Energy cost effectiveness:
This is a key performance indicator used to judge the productivity of a proves in terms of financial gain per unit of energy consumed.
Defined as output energy divided by input energy, and, if necessary, averaged over time. The electrical efficiency of an appliance is defined as the amount of that energy that is converted into a useful form, divided by the total energy it draws. For example, an incandescent light bulb (one with a filament inside the bulb) is said to be inefficient because much of the energy it uses (around 95 percent) is converted into heat rather than light. A fluorescent lamp that works on a different principle is somewhat more efficient because more of the energy it uses is converted into light and less is lost as heat (around 80 percent).
Engineering Procurement and Construction (EPC):
Term used to describe contracts in which a company assumes full responsibility for project engineering, material procurement and construction. The term is also used for companies contracted to perform these services.
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ERCB Directive 17
- Energy Resources Conservation Board (Alberta, Canada) directive stipulating the standards and requirements for measurement, accounting and reporting of oil, gas and liquids
FACTS (Flexible Alternating Current Transmission Systems):
Refers to a group of technologies that enhance the security, capacity and flexibility of power transmission and distribution systems. The technologies can be installed in new or existing power transmission and distribution lines. Examples of FACTS devices are: Static var compensation (SVC), uses an electrical device (see Static var compensator) to regulate and stabilize voltage in bulk power systems. The most advanced version of this technology is called SVC Light and has additional features, in particular more powerful flicker compensation to stabilize heavy and rapidly fluctuating loads, for example arc furnaces, and to smooth voltage flicker. Series Compensation can be fixed or controllable. The latter is called Thyristor Controlled Series Capacitor (TCSC). Series compensation is a straightforward and cost effective way to improve power transmission capacity and preserve voltage stability, particularly in bulk transmission corridors. Thyristor-controlled series compensation is especially useful for damping power oscillation over interconnections between transmission girds.
ABB’s FACTS devices optimize power flow to maximize the capacity of power lines and improve voltage stability by reactive power compensation (see Reactive power and Power factor compensation). In some cases, network capacity can be doubled. The equipment also makes the system more resilient to “system swings” and other disturbances.
Fault-closing device: A system of circuit breakers that serves to contain a fault in a grid, preventing it from spreading to other areas and causing widespread disruption.
Fault ride-through (FRT):
Refers to the ability of an electrical device (such as a wind turbine converter) to respond to a temporary fault or voltage change in the transmission and distribution grid, including a zero-voltage dip, and to help the system return to normal operation. Fault ride-through specifications are part of many grid code requirements.
Overhead lines or cables that are used to distribute electrical power to consumers. Feeders connect distribution substations and consumers.
A term that refers to crude oil, natural gas liquids, natural gas or other materials used as raw ingredients for making gasoline, other refined products or chemicals.
Frequency converter (frequency changer): At ABB, this term most commonly refers to a device used to adjust the frequency of alternating current. Frequency converters are a central component in variable-speed drives to control the speed, torque or power on the shaft of an electric motor by adjusting the frequency and voltage of the electricity powering the machine. Frequency converters are used to control the rotational speed of wind turbines to stabilize the frequency of the electricity they produce.
Frequency converters are also used to connect electrical systems operating at different frequencies. For example in shore-to-ship power connections, these devices are used to enable ships, most of which have onboard electrical systems running at 60 Hz, to onshore power supplies that most commonly run at 50 Hz.
A device in which chemical energy released by the oxidation of a liquid (such as methanol) or gaseous fuel is converted directly into electrical energy.
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Gas-insulated switchgear (GIS):
Gearless mill drive (GMD):
a system consisting of a ringmotor and its associated equipment such as transformers and control systems. Its main application is to drive (rotate) mills in the minerals or cement industry.
The generation mix is a term used to describe the contribution various sources of electricity make to the power supply serving a particular region or population. The portion of renewable energy in the global generation mix is rising in response to concern over climate change and increasing demand for electrical power.
A device that converts rotating mechanical movement into electric power. The current generated can be either alternating (AC) or direct (DC). ABB manufactures a range of generators, including wind-turbine generators. In a simple AC generator, a loop of wire is placed between the poles of a permanent magnet. The magnet is then rotated and the electromotive force produced by the movement of the electric field causes a current to flow in the wire. This is the principle of the synchronous motor and big generators in power plants. A DC generator operates on the same principle as the AC generator, but includes a device (a commutator), which effectively prevents the current from alternating.
Geographic Information System (GIS)
- systems that allow for the presentation and manipulation of real-time, historical and other data together with mapping applications to present information based on their geographic position.
This term refers to the requirements developed by power utilities that power generators of all kinds must meet to ensure the proper functioning and stability of the electrical transmission and distribution grid. that define grid fault and other conditions that must be responded to by wind power plants. These include regulations such as n-1 and fault ride-through capabilities (see n-1 and Fault ride-through).
Power utilities strive to maintain electricity supplies without unexpected dips or surges that can cause disruptions ranging from flickering lights to equipment damage. To avoid these problems, utilities therefore need to control the flow of power under normal running conditions and in emergency situations. This is done by installing sophisticated switching and protection equipment (fuses, circuit breakers, transformers, etc.) in substations, and monitoring equipment (protection relays, phase monitoring units, thermal line sensors etc) at strategic points on the grid. The monitoring units measure the rate and direction of power flow, its stability, the temperature of hot power lines, and other parameters critical to the normal functioning of the grid. The data are transmitted to a central computer, which uses them to calculate the settings for the control equipment housed in the substations and generating plants. This allows power flow to be directed, compensating for overloaded sections of the grid and even shutting down certain connections to prevent the spread of disturbances or to allow maintenance work to be carried out. (See FACTS, Network control, SCADA, Wide-Area Monitoring Systems.)
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Generally, harmonics are oscillations in the base power frequency. In electrical AC systems, the base frequency is typically 50 or 60 hertz (Hz) and harmonics occur in multiples of this, for example 100 Hz, 150 Hz, 200 Hz, etc. where the base frequency is 50 Hz. Harmonics occur whenever there is a disturbance of the voltage or current, eg, if the current is interrupted or if AC current is synthesized in a converter. The problem with harmonics is that electrical devices may react differently when exposed to a different frequency than the one they are designed for, which may cause damage. Harmonics are an increasing problem in power systems as most power electronics solutions cause harmonics. Harmonics can be reduced by the use of power filters.
Short spikes of high electrical current in a grid, caused by lightning strikes, or rapid switching of electrical devices in the grid, especially capacitors. These transients, or surges, cause cables to overheat, potentially damaging insulation and leading to short circuits. Equipment can be protected from high-current transients by using a surge protector.
High-voltage direct current (HVDC):
A technology developed by ABB in the 1950s to move large amounts of power over substantial distances - typically by overhead transmission lines, but also by way of submarine cables. Transmitting DC power over long distances is more efficient than AC transmission (see Direct current and Transmission and distribution) and is a cost-effective method of connecting two asynchronous grids (grids operating at different frequencies). An HVDC system takes electrical power from an AC network, converts it to DC at a converter station and transmits it to the receiving point by line or cable, where it is turned back into AC by using another converter. The conversion is carried out with high-power, high-voltage electronic semiconductor valves. These valves are controlled by a computer system, so the amount of transmitted power and also the direction of transmitted power can be precisely controlled, a feature unique to HVDC systems. Another important aspect of HVDC lines is that they can never be overloaded. Because HVDC transmits only active (real) power, no line capacity is wasted on transmitting reactive power. This means that the same power can be transmitted over fewer (or smaller) transmission lines than would be required using AC, and less land is needed to accommodate the lines. HVDC induces minimal magnetic fields, so the power lines may be built safely closer to human habitation.
In the 1990s ABB developed the HVDC Light technology which made it possible to have long underground transmission (see HVDC Light). In 2006 ABB carried out the first test circuit on +/- 800 kV ultrahigh-voltage DC (see Ultrahigh voltage).
Typical power and voltage range are:
Classical HVDC: 500 - 6,400 MW (± 150 - 660 kV)
UHVDC: 6000-8000 MW (± 800 kV)
HVDC Light: 100-1100 MW (± 150 - 320 kV)
Hoist, friction hoist: In underground mining, a hoist or winder is used to raise and lower conveyances within the mine shaft.
All hoists are powered using electric motors. Modern hoists are generally equipped with variable speed drives that minimize energy consumption and control the speed of the hoist.
An adaptation of classic HVDC, developed by ABB in the 1990s. It can be used to transmit electricity in lower power ranges (tens of megawatts) to an upper range of 1,100 megawatt (MW) (±320 kilovolts). By comparison, classic HVDC (see High-voltage direct current) systems typically transmit electricity in the 500 to 8,000 MW power range. Offering both HVDC and HVDC Light systems extends the economical power range of HVDC transmission.
The superior controllability is achieved by using IGBTs (ie, transistors) as the power electronic device used for the conversion (see Direct current).
HVDC Light offers the same benefits as traditional HVDC systems, but also provides more secure power control (superior to classic HVDC) and quick power restoration in the event of a blackout. Because of its superior ability to stabilize AC voltage at the terminals, it is the ideal technology for wind parks, where the variation in wind speed can cause severe voltage fluctuations.
HVDC Light is environmentally friendly, featuring oil-free cables, compact converter stations and cables that can be laid underground (thereby avoiding local planning difficulties associated with overhead lines) as well as underwater. It is the only technology available that allows long-distance underground high-voltage transmission. It is rarely used for power transmissions using overhead lines. Because of its smaller footprint, underground cable technology and superior controllability, HVDC Light has many more potential applications than classical HVDC, for example: feeding power into cities and offshore oil and gas platforms; strengthening power networks in areas where there is opposition to new overhead lines; and delivering power to islands that would otherwise need local generating plants.
High-voltage shore connections enable ships to draw electricity from onshore power grids while in port to operate onboard equipment such as lighting, cooling and heating systems, instead of burning fuel oil to run onboard generators. For a large cruise ship on a 10-hour stay in port, a shore connection can cut fuel consumption by up to 20 tons and reduce carbon dioxide emissions by 60 tons.
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A device that enables communication between electronic equipment and external devices, including human operators. Examples of I/O devices include computer keyboards, printers, sensors and all type of interface cards.
The International Electrotechnical Commission IEC standard for substation automation replaces a great many communication protocols that require the use of use protocol converters, which are basically “translators” that help electronic devices using different machine languages transmit information to each other. The problem is that protocol converters can cause messaging errors and delays. A single communication standard for substation automation removes the need for “translators,” helps customers lower maintenance and operating costs, and makes installations easier to expand or modify.
A series of interoperable software and hardware products and systems from ABB and/or third parties that are designed to communicate with each other and work together as part of a larger system for a specific application.
Raising industrial productivity means lowering costs for each unit (eg, car, ton of paper, etc.) produced. Manufacturers are under intense pressure to improve productivity and performance to remain competitive, and avoid losing business to more efficient rivals. New technologies and business models are allowing companies to restructure their business processes - things like procurement, manufacturing, research, sales, distribution, and so on - establishing new combinations and locations that enable them to work more closely with partners, suppliers, and customers. Productivity improvements can be achieved by automating operations, improving the asset management, optimizing factories operations, outsourcing, and improving the supply chain management.
In contrast to most transformers (which are used to convert power), instrument transformers are components of devices used for measurement or monitoring (eg, to measure voltage or current in transmission lines). As they do not actually transform any significant quantities of energy they are usually small and lightweight.
A method used to measure the status of equipment by analyzing the amount of heat it radiates.
Electronic or electromechanical devices, often referred to as meters, used to measure the flow, level, temperature and pressure of processes in different industrial applications. They monitor processes in power generation, manufacturing and refining plants. Information collected by various instruments is processed by analyzers and used to assess performance, sending alerts if readings are not as expected.
A material that does not conduct electric current, such as plastic, some kinds of silicon or glass. The term can also refer to a material that does not conduct heat. For clarity, the terms thermal insulator and electrical insulator may be used. (See also Conductor.)
Integrated solar combined cycle (ISCC):
Type of hybrid power plant where thermal energy from a concentrating solar power field is integrated into a combined cycle power plant. Such a combination allows the plant to increase output while reducing fossil fuel consumption and associated CO2
emissions. The same hybrid technology can be applied to coal or biomass power plants.
Integration of renewable energy:
Feeding electricity from intermittent sources of energy such as wind and solar into the power network without causing any disturbance to the power supply.
An electrical device for converting direct current (DC) into alternating current (AC). (See also Rectifier.)
If a material is exposed to high temperatures or an electrical field, it can become ionized, ie, its particles can become electrically charged. Also known as plasma, ionized gases can enable an electric current to jump across a gap in an electric circuit. To avoid this problem, circuit breakers are equipped with various insulators that inhibit arc formation. See also Circuit breaker.
International standards for quality assurance set by the International Standards Organization. It includes some 20 elements of quality process performance, and is a prerequisite for delivering predictable, quality products to customers.
International standards for environmental management systems set by the International Standards Organization.
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Key performance indicator (KPI):
A measurable objective used by organizations to monitor progress towards a specific goal. Such measures are commonly used to define and evaluate an organization’s performance against internal benchmarks or those of peer organizations.
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An automated factory that requires no light because no people work in it.
Line thermal monitoring (LTM):
Process that measures average power-line temperature and detects temperature changes in power lines. It is important because heat causes wires to expand and sag, resulting in short circuits, fires and blackouts if they contact treetops etc. (See also Wide-Area Monitoring System.)
A load in electrical terms is the power consumed by a device or a circuit. Load is also used to describe the total of all electricity consumers in a power system.
Controlling loads in a utility system to limit peak demand, reduce costs, improve load factor, or in some other way improve the stability and reliability of electrical power distribution.
Load tap changer (LTC):
load tap changers are devices used to adjust the performance of transformers. Adjusting the tap changes the voltage of the transformer’s input or output.
Inadvertent transmission of power through an unnecessary diversion in the transmission network. It is undesirable because it serves no purpose and incurs losses.
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Motors and generators are collectively referred to as “machines” or “electric machines.” Motors are machines that convert electrical energy into mechanical work in the form of a rotating shaft, while generators convert the mechanical work of a rotating shaft into electricity.
The speed of a “synchronous” machine, ie, the rate at which its shaft rotates, is dictated by the frequency of electricity in the grid to which it is connected. The speed of a synchronous machine is accurately predictable. This means that it maintains its speed irrespective of the load placed on it.
Because synchronous motors can maintain a particular speed with extreme accuracy, they are used in performance-critical applications such as mechanical clocks and DVD drives. Synchronous generators are commonly used in power plants, where their predictable, consistent performance helps to maintain the quality and reliability of power supplies. Synchronous generators are also referred to as alternators.
The speed of an asynchronous machine is slightly slower than the frequency of the electricity it consumes or generates. Asynchronous motors slow down as their load increases and asynchronous generators change speed with the torque (rotational force) that is applied to their rotors.
Asynchronous machines are also referred to as induction motors/generators.
an arrangement of connected pipe and valves used to consolidate multiple pumps, tanks, and/or pipelines and a single unit.
Maximum power point tracking:
Feature of a power conditioning unit through which photovoltaic modules are operated at their optimal power production.
In the wind power industry, this term refers to the combination of the turbine’s main rotor shaft and bearings, gearbox (if used) and generator.
One million VAr (volt-ampere reactive).
One million VA (volt-ampere).
One million watts. One megawatt would be needed to light 10,000 one-hundred-watt light bulbs. If those bulbs were powered for 1 hour, 1 MWh of electrical power would be used. (See also Watt and Watt hour.)
A microgrid is a small-scale power network that comprises generating units and consumers. Often including renewable power sources such as wind turbines and solar panels, microgrids may also be connected to the larger-scale grids from which they can draw power if locally generated supplies fail to meet demand.
A small turbine generator of 30 - 250 kilowatts (kW) generating capacity, which can be located near a customer load.
A substation that can be transported, usually by truck, to temporarily replace equipment at the site of a failure or in the event of planned maintenance.
Model predictive control (MPC):
The online control of an industrial process (such as oil refining) that uses a virtual model of the process, which allows a computer to predict appropriate control settings.
Motor control center (MCC)
- A combination of one or more switching devices together with associated control, measuring, signaling, protective, regulating equipment contained within an assembly for the primary purpose of controlling, protecting and operating electric equipment, including but not limited to motors and variable speed drives.
An HVDC transmission with more than two stations, which enables either to tap off power in a station (or stations) in the middle or to feed in more power in the middle of the transmission link.
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