Glossary of electric industry, energy & cooperative terms

V

Valley
The internal angle formed by the junction of two sloping sides of a roof.

Vapor Barrier
Material used to protect against condensation in insulation; can be of polyethylene sheeting, foil-backed gypsum board, or other material.

Vent
A means of air or moisture escaping or leaving a confined space.

Ventilation
The process of supplying or removing air, by natural or mechanical means, to or from any space.

Vertical Integration
An arrangement whereby the same company owns all the different aspects of making, selling, and delivering a product or service. In the electric industry, it refers to the historically common arrangement whereby a utility would own its own generating plants, transmission system, and distribution lines to provide all aspects of electric service.

Vertically-Integrated Utility
A utility company that sells power on a bundled basis and whose activities encompass the full range of different functional activities (e.g. generation, transmission and distribution.)

Voltage
The electric pressure of a circuit in an electric system measured in volts. It is generally a nominal rating based on the maximum normal effective difference of potential between any two conductors of the circuit.

Voltage Reduction
Any intentional reduction of system voltage by 3 percent or greater for reasons of maintaining the continuity of service of the bulk electric power supply system.

Voltage Regulator
An electrical device that regulates voltage flowing through distribution lines. It automatically raises and lowers the voltage to maintain required voltage levels for service.

Volt-Ampere (VA)
A unit of electrical force equal to the product of voltage and total current in amperes. The formula is: Volts x Amperes = Volt-Amperes (VA). The volt-ampere is the basic unit of apparent power.

Volt-Ampere Reactive (VAR)
The basic measure of reactive power. Reactive power is the portion of apparent power (volt-amperes) that serves no useful purpose.

Volts
The unit of measurement of electrical force or pressure. The volt is analogous to water pressure in pounds per square inch. One volt equals the electrical force that, if steadily applied to a circuit with a resistance of one ohm, will produce a current of one ampere. For a pipe of a given size, raising the water pressure increases the capacity of the pipe to deliver water. Similarly, for a wire of a given size, raising the voltage (pressure) results in an increase in the capacity of that wire to deliver energy. High voltages are used in the transmission lines that transport large amounts of electricity.

Volumetric Wires Charge
A type of charge for using the transmission and/or distribution system that is based on the volume of electricity that is transmitted.

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Page last updated: Friday, March 5, 2010