Like many fields of knowledge, the electric power industry is full of terms and acronyms that can be difficult for non-experts to understand. If you don't know your amps from an electrical ground, this guide to electric system lingo can help power your industry knowledge.
Amperage. The amount of electrical current that is flowing through a circuit, or the maximum amount of current that a circuit can handle safely. it's measured in amperes or amps.
Circuit. A path for transmitting electric current. Every circuit includes a power source (generator), an energy using devices (lights, motors) and a connecting wire or power line.
Current. The flow of electric charge through a circuit. Direct-current (DC) moves continuously in one direction. Alternating current (AC) changes direction 60 times per second.
Demand. The rate at which a device or facility consumes electricity. A 10 kW (10,000-watt) motor draws 10,000 watts of power at any given time while it’s running at full speed.
Distribution. The final stage of the delivery of power. A distribution system includes substations, power lines, transformers and other equipment that delivers to customers at the right voltage.
Generation. Electricity created by a generator, a device that converts some form of energy into electricity. Utility-scale generators use fossil fuels, falling water, solar and wind energy and nuclear reactions.
Grid. A network of power plants, substations, transformers, power lines and other equipment that delivers electricity from the source of generation to customers.
Ground. A common return path for electric current in a circuit. Exposed conductive parts of electrical equipment are connected to ground to protect users from potential shock hazard.
Interconnection. The U.S. grid is comprised of three major regions — The Eastern Interconnection, The Western Interconnection and the Electric Reliability Council of Texas. Each region contains interconnected local utility grids.
Kilowatt (kW). A kilowatt is equal to 1,000 watts of power. It's a measure of the rate of electricity generation or consumption.
Kilowatt-hour (kWh). A measure of the amount of electricity a device uses when it's running. If a device uses 1,000 watts over an hour, that’s a kilowatt-hour.
Microgrid. Localized grids powered by distributed generators, batteries or renewable sources. They can operate as part of the larger grid or as an independent source of electricity.
Phase. The distribution of an electrical load in a circuit. Single-phase circuits have one power wire and one neutral wire. Three-phase circuits have three power wires carrying the load. Because voltage peaks and dips in a cycle, single-phase power supply isn't consistent. Three-phase circuits separate the peaks and dips, delivering power at a constant rate.
Power factor. The difference between real power (that which electric devices use to operate) and apparent power (additional magnetic power required by some devices). Expressed between 0 and 1, a low power factor means more apparent power is used.
Smart grid. A set of advanced technologies — such as smart meters, sensors, microgrids and energy storage -designed to improve grid connectivity, efficiency and reliability.
Substation. A set of equipment that increases power voltage for transmission or reduces voltage for distribution to customers.
Switchgear. A set of circuit protection devices (breakers, fuses and switches) housed in a metal structure designed to control and isolate electrical equipment.
Transformer. A device that transfers electric current from one circuit to another, either increasing (stepping up) or reducing (stepping down) voltage.
Transmission. The initial stage of power delivery. Transmission lines carry extremely high-voltage power over long distances to distribution substations.
Voltage. The pressure from a power source that pushes current through a conductor, such as a power line. It's measured in volts (V).
Watt. A unit of electric power that measures the rate at which energy is expended per unit of time. A 40-watt lightbulb draws 40 watts of power at any given time.
See this glossary of electric industry terms from the U.S. Energy Information Administration for more information.