Glossary by "A"
The ability of the electric system to supply the aggregate electrical demand and energy requirements of the end-use customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements.
Of, relating to, or being a reversible thermodynamic process that occurs without gain or loss of heat and without a change in entropy.Source: thefreedictionary
Adverse reliability impact
The impact of an event that results in frequency-related instability; unplanned tripping of load or generation; or uncontrolled separation or cascading outages that affects a widespread area of the Interconnection.
Alberta Electric System OperatorAcronym(s): AESO
Agency responsible for the safe, reliable and economic planning and operation of the Alberta Interconnected Electric System (AIES). Provides 1. open and non-discriminatory access to Alberta’s interconnected power grid for generation and distribution companies and large industrial consumers of electricity, 2. contracts with transmission facility owners to acquire transmission services and 3. with other parties; provide fair and timely access to the system, 4. develop and administer transmission tariffs, 5. procure ancillary services to ensure system reliability and 6. manage settlement of the hourly wholesale market and transmission system services.
Allowance for funds used during constructionAcronym(s): AFUDC
AFUDC is an accounting practice whereby the costs of debt and equity funds used to finance plant construction are credited on the statement of income and charged to construction in progress on the balance sheet.Source: ESA Technical Working Group
Alternating currentAcronym(s): AC
Flow of electricity whose polarity/voltage changes (alternates) between positive and negative. The majority of power produced by electric utilities in the U.S. the form of current that alternates at a rate of 60 cycles per second (Hz), also known as the fundamental frequency. In Europe and elsewhere the fundamental frequency is 50 Hz.Source: ESA Technical Working Group
American National Standards InstituteAcronym(s): ANSI
The organization responsible for approving U.S. standards in many areas, including computers and communications. Standards approved by this organization are often called ANSI standards.Source: Energy Vortex
Amp hoursSee: Ampere hoursSource: ESA Technical Working Group
Ampere hoursSee: Current
A unit of measurement of the amount of current that can or does flow over a given amount of time. See also current.Source: ESA Technical Working Group
Those services that are necessary to support the transmission of capacity and energy from resources to loads while maintaining reliable operation of the Transmission Service Provider’s transmission system in accordance with good utility practice. (From FERC order 888-A.)
ANSISee: American National Standards Institute
Area control errorAcronym(s): ACE
The instantaneous difference between a Balancing Authority
The extent to which an asset is used relative to the maximum amount of use that is possible. For example, an asset that could be used throughout he entire year and that is only used during half of the year has an asset utilization of 50%. Another relevant metric for electric utility assets is kWh generated, transmitted or delivered per kW of (asset) rated capacity.Source: ESA Technical Working Group
Automatic generation controlAcronym(s): AGC
Equipment that automatically adjusts generation in a Balancing Authority Area from a central location to maintain the Balancing Authority
Available transfer capabilityAcronym(s): ATC
1. A measure of the transfer capability remaining in the physical transmission network for further commercial activity over and above already committed uses. It is defined as Total Transfer Capability less existing transmission commitments (including retail customer service), less a Capacity Benefit Margin, less a Transmission Reliability Margin. 2. The amount of additional [transmission] capability available in the transmission network to accommodate additional requests for transmission services.
The revenue requirement of a utility divided by the utility.