All-aluminum conductor. See conductor.
See air-to-air heat exchanger.
Reducing the degree or intensity of, or eliminating pollution or noise.
See alternating current.
See area control error.
See air changes per hour.
The process of nitrogen and sulfur oxides in the atmosphere coming into contact with water resources, plant and animal life, and components of the electric power system. May be in the form of rain, snow, or particulates.
Rain that contains nitrogen and sulfur oxides, usually with pH of 4 to 7.
The term commonly used at BPA for purchase of power. BPA is prohibited by law from owning a power project and its facilities. See resource acquisition.
The land rights acquired by BPA can range from full fee title to perpetual non-exclusive easement to short-term permits and depend on the type of facility being installed.
The volume of water that will cover a one-acre area to a depth of one foot; often used to describe a quantity of storage in a reser-voir; one acre-foot equals 1233 cubic meters (325,000 gallons) of water.
Aluminum conductor steel reinforced. See conductor.
See Pacific Northwest Electric Power Planning and Conservation Act.
1) In various regulatory programs, the point at which a response is called for. 2) In the Federal Superfund program for cleanup of hazardous waste, the existence of a contaminant concentration in the environment high enough to warrant action or trigger a response under the Superfund Amendments and Reauthorization Act of 1986 or the National Oil and Hazardous Substances Contingency Plan.
See real power.
Mechanical devices and an external energy source, in addition to solar energy, used to collect, store, and distribute thermal energy.
See computed requirements.
See analog-to-digital converter.
The chief executive officer of BPA, appointed by the Secretary of the U.S. Department of Energy.
The reciprocal of electrical impedance; admittance is expressed in the same units as conductance (mhos) and impedance in the same units as resistance (ohms).
See trust fund.
A wind-induced conductor vibration (up and down) having small amplitudes but may have high vibration speeds. Also spelled eolian.
A sign installed on the first tower or structure in each mile of each transmission line and located on both faces of the uppermost part of the structure as an aid to the aerial observer in identifying the structure numbers.
Signs installed on the uppermost part of a steel tower or wood pole structure to designate it as a flight hazard to aircraft oper-ators; BPA uses four signs: 1) Danger, to indicate any dangerous condition; 2) Static, to indicate overhead ground-wire crossing ahead; 3) Airport; 4) Detour, to advise pilot to avoid area ahead, such as a turkey or mink farm. Sign types 1, 2, and 3, have white letters on a red background; sign type 4 has black lettering on a yellow background.
See allowance for funds used during construction.
See automatic generation control.
A defined area in which air-borne pollutants tend to circulate and mix together.
The movement of a volume of air in one hour; if a house has one ACH, it means that all of the air in the house will be replaced in one hour.
A geographically isolated volume of air, usually above and/or downwind from industrial activity, that bears pollutants away for dilution and dispersal.
A device that exchanges indoor air with outdoor air, warming or cooling the incoming air with the air being exhausted.
Lights installed on structures according to Federal Aviation Administration regulations to designate flight hazards during darkness.
A colored ball, usually orange, gloss white, or gloss yellow, attached to the conductors or overhead ground wire on a transmission line to increase their visibility. Also called aviation marker ball.
The painting of transmission line structures according to Federal Aviation Administration regulations to designate flight hazards during daylight.
At BPA, a neon light mounted on transmission and radio towers in accordance with Federal Aviation Administration regulations to designate a flight hazard.
The allocation of asset costs to customer groups or market segments.
In ratemaking, a measure of electric power usage that apportions respon-sibility for the use of resources or services among customer classes, usually expressed as a percentage.
The interest on debts issued to finance construction work-in-progress, normally financed through borrowing and eventually paid by ratepayers after projects are completed and placed in service.
A low cone-shaped deposit of material laid down by a swift-flowing stream as it enters a plain or an open valley.
A positively charged particle, emitted by certain radioactive materials, made up of two neutrons and two protons bound together, hence identical with the nucleus of the helium atom; the least penetrating of the three common types of radiation (alpha, beta, gamma), it is stopped by a sheet of paper. Not dangerous to plants, animals or humans unless the alpha-emitting substance has entered the body.
An electric current or voltage that reverses direction of flow periodically, as contrasted to direct current, and has alternately positive and negative values. Most electricity used in the U.S. today is alternating current.
Conductor made from aluminum-covered steel. Stranded conductor of alumoweld is commonly used for overhead ground wire.
The normal or average prevailing quality of the surrounding air in a given area in terms of the type and amounts of various air pollutants present.
The normal or average background noise level (usually recorded in decibels) within a given area for a certain period of time during the day.
1) The temperature of the air surrounding an object or person, such as the temperature inside a room. 2) The temperature of the surrounding cooling medium, such as gas or liquid, which comes into contact with the heated parts of electrical equipment and into which the heat of the equipment is dissipated.
A national service organization representing more than 1,750 local, publicly owned electric utilities.
An electrical instrument, with a scale usually graduated in amperes, placed in a circuit to measure the magnitude of electric current.
A low-impedance winding consisting of conductors embedded in the pole shoes of a synchronous machine, such as a generator, and connected together at the ends of the poles. Used to oppose rotation or pulsation of the magnetic field of the machine with respect to the poles. Also called damping winding.
The repayment to the U.S. Treasury by BPA of principal on the Federal investment in the Federal Columbia River Power System (FCRPS), which includes BPA bonds and appropriations, and Army Corps of Engineers and Bureau of Recla-mation appropriations that are part of the FCRPS.
Current-carrying capacity, expressed in amperes, of a conductor or cable under stated thermal conditions.
A unit of measurement of electric current, which is the rate that electrons flow in a wire; one ampere is 6.023 x 1023 electrons per second. The measurement is similar to gallons per minute of water in a pipe.
A device for increasing the power associated with a phenomenon without appreciably altering its quality and in which an input signal controls power from a source independent of the signal and delivers an output that bears some relationship to, and is generally greater than, the input signal.
The absolute value of the maximum displacement from a zero value during one period of an oscillation. The maximum deviation of an alternating current from its average value during its cycle.
The process whereby the amplitude of one electrical quantity is varied in accordance with some selected characteristic of a second quantity, not necessarily electrical (for example, in microwave voice communications, a wave oscillating at the relatively low frequency of sound would be used to vary the amplitude of a continuous high-frequency transmitted carrier wave).
See average megawatts.
Species of fish that hatch and initially grow in freshwater, migrate to and mature in the ocean, and return to freshwater as adults to spawn (such as salmon or steelhead trout).
A device that converts analog information into one of many digital formats.
A device that stabilizes a transmission structure with respect to the ground.
Normally a metal plate buried in the ground to which an anchor rod is attached.
Buried logs that brace a wood pole; used in marshy and swampy terrain; also called swamp brace or brace anchor.
Metal rod that forms the connection between the guy anchor and guy wire.
A visual signaling device indicating one or more conditions that exist or have existed in an associated circuit and which usually requires personal attention.
The electrode by which current enters a mercury arc or solid-state valve (thyristor) in the conversion from alternating current to direct current. Current flow is from anode to cathode.
A device for radiating or receiving electromagnetic waves.
A percentage reflecting the number of customers in a given customer class who own a particular type of energy-using equipment.
The statutory authority that allows a Federal agency to incur financial obligations. The U.S. Army Corps of Engineers and Bureau of Reclamation also use Federal appropriations to finance their generating projects. BPA does not receive appropriations. See borrowing.
The plant and animal life of a water body, considered as a total ecological entity.
The discharge of electricity through air or other gas occurring across a gap or set of electrodes.
The process of current flowing across a gap, such as fault current flowing across an insulator string that flashed over due to a lightning surge.
A number determined in the regulation of the power output of electric generators within a control area (automatic generation control) indicating how much the generation in a power system area deviates from load. The total ACE is subdivided into a schedule of station control errors and transmitted to power plants for the readjustment of specific generators.
The offices that serve as BPA’s main contact with its customers in four areas — Puget Sound, Lower Columbia, Upper Columbia, and Snake River. Also see District offices.
Protective helically formed wires wrapped around conductor to prevent damage at point of support; also used to repair minor conductor damage.
Average system cost. See costs.
The quotient that results from dividing total operating expenses by allocated assets. This ratio measures the relationship between operating assets and their cost of operations.
Payments to the U.S. Treasury for: Bureau of Reclamation operation and maintenance, loan interest, and principal on loans; Corps of Engineers operation and maintenance; and the Federal Energy Regulatory Commission portion of the coordination agreement for downstream benefits realized at non-Federal dams.
The anticipated date of operation of a resource, allowing for average planning and construction times.
See intertie access.
Firm transmission service provided by BPA under a transmission contract to wheel power covered by a contract between a scheduling utility and a Southwest utility.
The studies that determine the operating rules for the three Columbia River Treaty projects in British Columbia, Canada. See operating plan.
A geographic region where the concentration of a criteria air pollutant does not exceed national ambient air quality standards.
In communication, a decrease in magnitude of a signal.
A device for reducing the power level or the amplitude of a signal without introducing distortion. Commonly a combination of fixed or adjustable resistances.
Any frequency corresponding to a normally audible sound wave; can range roughly from 15 hertz to 20,000 Hz; frequently shortened to "audio" and used to refer to a device or group of devices intended to operate at audio frequencies.
The legislation enacted by Congress which sets up or continues the legal operation of a Federal program or agency indefinitely or for a specific period of time, or permits a particular type of obligation or expenditure within a program.
See circuit recloser.
The regulation of the power output of electric generators within a control area in response to changes in load, system frequency, and other factors to maintain the scheduled system frequency and interchanges with other control areas.
A fee, in a rate schedule or as negotiated, to ensure that a generating resource is capable of producing energy at a time or times it might otherwise be in a maintenance cycle or unavailable.
The ratio of the time a piece of equipment or a unit is ready for or in service to the total time interval under consideration.
Water that is not dedicated or reserved for other purposes. For power purposes, water that is not already dedicated for irrigation, navigation, municipal, or other use.
A measure of change that takes into account the compounding of change that takes place over time. Similar to compound interest paid on a savings account.
See average megawatts.
In electric utility usage, the pricing of the service to recover the total costs associated with that service.
The total power produced over a period of time divided by the number of hours in the period of time. Can be expressed in kilowatthours/day, megawatthours/month or average megawatts.
The unit of energy output over a year, equivalent to the energy produced by the continuous operation of one megawatt of capacity over a period of time; also an average of one million watts transferred over a period of time (often a year, thus average annual megawatts).
Benefits received by participating utilities for the purpose of reducing the retail rates of residential and small-farm customers. The benefit is computed as the difference between a utility’s ASC and BPA’s priority firm rate and then multiplied by the qualified residential and small-farm load.
The method used to compute and pay for a utility’s average transmission and production-related costs for the purpose of an exchange of power between BPA and a utility under section 5(c) of the Pacific Northwest Electric Power Planning and Conservation Act.
See airway marker ball.
A method used to determine the payments from utilities to qualifying facilities (QFs) that produce or cogenerate power under the Public Utility Regulatory Policies Act. The utility pays the QF an amount based on the costs for power the utility avoids by purchasing power from the QF.