Grid equipment and concepts

Distributed generation

Distributed generation, also known as distributed or decentralized energy, is the production of electricity at or near the point of use, including rooftop solar and small wind.

Distribution automation

Distribution automation is the use of sensors, communications, and automated switching on the electric distribution grid to detect, isolate, and restore faults, reducing outage duration and extent.

Distribution board

A distribution board, also known as a breaker panel or fuse box, is an enclosure dividing an electrical supply into separate circuits protected by fuses or circuit-breakers.

Distribution system state estimation

Distribution system state estimation (DSSE) is a power systems method that infers voltage magnitudes and angles across a distribution feeder from limited real-time and pseudo-measurements.

Distribution transformer

A distribution transformer, also called a pole pig or service transformer, makes the final step in voltage reduction, converting medium grid voltage to the low voltage used by homes and businesses.

DLMS/COSEM

DLMS/COSEM (IEC 62056) is an international standard suite for smart energy metering, combining the DLMS application layer and the COSEM object model, standardized since 2002.

Dorsey Converter Station

Dorsey Converter Station is an HVDC converter station in Rosser, Manitoba, where electricity from northern Nelson River hydro stations is converted back to AC, carrying over 70% of Manitoba's power.

Droop control is a decentralized control method in which parallel-connected inverters and generators share active and reactive power from local measurements alone, with no communication links, making it the most implemented approach for islanded microgrids.

Dry-type transformer

A dry-type transformer is a power or distribution transformer insulated and cooled by air and solid materials like epoxy resin instead of oil, favored indoors for fire safety.

Dunkelflaute

Dunkelflaute, German for "dark wind lulls", is a period of days with low wind and sun that leaves wind and solar power generating very little electricity.

Dynamic line rating

Dynamic line rating (DLR) is a power-systems technique that sets an overhead transmission line's capacity from real-time weather, typically raising usable capacity 10 to 30% over static ratings.

Dynamic power cable

A dynamic power cable is a submarine power cable connecting a floating offshore structure, usually a floating wind turbine, to the seabed while moving with waves and currents.

Dynamic voltage restorer

A dynamic voltage restorer (DVR) is a series-connected custom power device that injects corrective voltage to protect sensitive loads from sags, swells, and other disturbances, but not outages.

Earth potential rise

Earth potential rise (EPR), also called ground potential rise, is the voltage an earthing system, such as a substation ground grid, attains relative to remote earth during a fault.

Earthing switch

An earthing switch is a mechanical switching device that connects de-energized circuits or high-voltage equipment to earth potential, protecting personnel during maintenance; it is standard in substations and governed by IEC 62271-102.

Earthing system

An earthing system, also known as a grounding system, is the set of conductors and electrodes connecting an electrical installation to earth, ensuring safe fault clearance.

Economic dispatch

Economic dispatch is an optimization method in power systems engineering that allocates scheduled generation among online units to minimize total fuel cost while meeting demand and operating limits.

Edison screw

The Edison screw, also known as the Edison base, is the threaded lamp cap and socket system, introduced by Thomas Edison in 1880, used to secure light bulbs.

Electric power distribution

Electric power distribution is the final stage of the electricity supply chain, delivering power from distribution substations to customers at voltages from 4 kV down to 120 V.

Electric power transmission

Electric power transmission is the bulk movement of electricity from power plants to load centers over high-voltage lines, kept separate from the lower-voltage distribution system serving homes and businesses.

Electrical treeing

Electrical treeing is a pre-breakdown degradation process in which branching channels grow through solid electrical insulation, the primary failure mode of polymeric high-voltage cable insulation.

Electricity meter

An electricity meter, also called a kilowatt-hour or energy meter, is a device that measures electrical energy consumed by a customer in kilowatt-hours for billing.

Elster (metering company)

Elster is a metering brand and former company group that makes gas, electricity, and water meters, acquired by Honeywell from Melrose Industries in 2015 for about $5.1 billion.

EN 50160

EN 50160 is a CENELEC European standard, titled Voltage characteristics of electricity supplied by public electricity networks, defining expected voltage quality at user supply terminals.

Engineering Recommendation G99

Engineering Recommendation G99, also known as EREC G99, is an Energy Networks Association standard governing connections of solar, wind, and battery generation to Great Britain's distribution networks.

Equipotential bonding

Equipotential bonding is the electrical interconnection of conductive parts of an installation to the earthing system so no dangerous voltage difference appears between touchable surfaces during faults.

Equivalent salt deposit density

Equivalent salt deposit density (ESDD) is an insulator pollution measure: the sodium chloride mass giving the same conductivity as the deposit, per unit surface area, in mg/cm².

Eugene C. Sakshaug

Eugene C. Sakshaug (1923–2016) was an American electrical engineer who spent 32 years at General Electric developing surge arresters, and was elected to the National Academy of Engineering in 1986.

F. Don Tan

F. Don Tan is a power electronics and energy systems engineer, elected to the National Academy of Engineering in 2025, who led space power conversion at Northrop Grumman.