353 articles
765 kV
765 kV is a voltage level for extra-high-voltage AC power transmission, the highest used in North America since 1969 and a backbone voltage for bulk power transfer in India.
AC power plugs and sockets
AC power plugs and sockets are connectors that link appliances to the AC mains supply, with plug types A through O defined by national standards.
AC power plugs and sockets: British and related types
The British plug and socket system, standardized as BS 1363 and known as Type G, is the 13-ampere, fused, three-pin plug system used in the United Kingdom and Ireland.
Active neutral-point-clamped converter
The active neutral-point-clamped (ANPC) converter is a three-level voltage-source converter topology that replaces the clamping diodes of the NPC converter with active switches, balancing losses among devices.
Adaptive protection (power systems)
Adaptive protection is power system protection in which relay settings are adjusted online to match prevailing network conditions, developed since the 1980s for distribution networks.
Advanced metering infrastructure
Advanced metering infrastructure (AMI) is the integrated system of smart meters, two-way communication networks, and data management systems that electric utilities use to measure consumption automatically and act remotely.
Aeolian vibration
Aeolian vibration is a high-frequency, low-amplitude oscillation of overhead power line conductors caused by wind flowing across them, and the leading cause of fatigue damage at conductor clamps, countered by Stockbridge dampers.
Air circuit breaker
An air circuit breaker (ACB) is a circuit breaker that extinguishes its arc in air, used in main distribution switchgear and once common on high-voltage transmission systems.
Air-blast circuit breaker
An air-blast circuit breaker is a high-voltage circuit breaker that interrupts current by blasting compressed air at the arc; invented in 1926, it dominated extra-high-voltage switching until about 1990.
Air-insulated switchgear
Air-insulated switchgear (AIS) is electrical switchgear in which ambient air insulates live conductors from each other and from grounded enclosures, in contrast to gas-insulated switchgear.
Alexander Apostolov (Александър Апостолов)
Alexander Apostolov (Александър Апостолов), born 1949 in Sofia, Bulgaria, is a Bulgarian-born American power systems engineer at OMICRON, elected to the US National Academy of Engineering in 2025 for leadership in digital protection and control.
Aluminium conductor composite core
Aluminium conductor composite core (ACCC) is a high-temperature, low-sag overhead power conductor with a carbon and glass fiber composite core, first commercialized in 2005 by CTC Global.
Aluminium conductor steel-reinforced cable
Aluminium conductor steel-reinforced cable (ACSR) is a bare overhead conductor with aluminum wires stranded around a coated steel core, the standard for overhead transmission lines since the early 1900s.
American Superconductor
American Superconductor is an American power technology company, founded in 1987, that builds grid control systems, superconductor cables, and electronics for wind turbines and the U.S. Navy.
Apparent power
Apparent power, written S, is the product of rms voltage and rms current in an AC circuit, measured in volt-amperes; transformers and UPS systems are rated in it.
Arc chute
An arc chute is a chamber in a circuit breaker that draws out, divides, and extinguishes the electric arc formed when the breaker's contacts separate under load.
Arc-suppression coil
An arc-suppression coil, also called a Petersen coil or ground-fault neutralizer, is an inductive reactor between a power system's neutral and earth that cancels ground-fault current so arcs self-extinguish.
Area control error
Area control error (ACE) is the real-time difference between a balancing authority's actual and scheduled net power interchange, adjusted for frequency bias, that automatic generation control drives toward zero.
Audible noise (transmission lines)
Audible noise from transmission lines is sound from corona discharge on energized conductors, worst in wet weather, with a broadband crackle and a low 120 Hz hum.
Automatic generation control
Automatic generation control (AGC), also called load frequency control, is the secondary control layer of a power grid that adjusts generator setpoints to restore frequency and hold tie-line schedules.
Automatic reclosing
Automatic reclosing (autoreclose) is the process by which a circuit breaker that has tripped on a fault closes again automatically, restoring service after temporary faults.
Autotransformer
An autotransformer, also called an autoformer, is a transformer with a single winding per phase, part shared by primary and secondary, offering copper savings but no electrical isolation.
Back flashover
Back flashover is a flashover of a transmission line insulator from the tower side to the phase conductor, caused by a lightning stroke to the tower or shield wire raising the tower's potential.
Back-to-back converter
A back-to-back converter is an HVDC arrangement in which a rectifier and inverter share one station, connecting AC grids that are not synchronized, with no transmission line between them.
Baixas converter station
The Baixas converter station is an HVDC converter station near Perpignan, France, the French end of the underground France–Spain interconnection, built by INELFE and opened in 2015.
Ball and socket coupling
A ball and socket coupling is the standardized joint connecting string insulator units to each other and to fittings on high-voltage overhead power lines, standardized in IEC 60120.
Basic insulation level
The basic insulation level (BIL), formally the basic lightning impulse insulation level, is the peak lightning impulse voltage that power equipment insulation must withstand without breakdown.
Berkshire Transformer Consultants
Berkshire Transformer Consultants was the worldwide transformer-consulting practice of William J. McNutt, a General Electric engineer and IEEE Life Fellow elected to the National Academy of Engineering in 2000.
Black start
Black start is the procedure for restoring a power grid after a total or partial blackout, using generators that start without external power, energize transmission lines, and restart larger plants.
Booster transformer
A booster transformer, also called a buck-and-boost transformer, is a transformer whose secondary is connected in series with a power line to boost or buck the voltage.