GLOSSARY OF ELECTRICAL AND UTILITY RELATED TERMS
A & G -Abbreviation for administrative and general expenses.
AC - Alternating current, the type of electrical current produced in a rotation generator (alternator), which changes both magnitude and direction. Measured in volts. The speed or number of times it changes direction in a second is called frequency. Industry standard on frequency is 60 cycles per second, which means the electricity changes direction 60 times per second. Current from wall socket.
Access Charge - A fee paid by the user to the utility for the ability to send or receive electricity through its transmission or distribution systems.
Accessible (as applied to wiring methods) (National Electrical Code) - Capable of being removed or exposed without damaging the building structure or finish, or not permanently closed in by the structure or finish of the building.
(as applied to equipment) (National Electrical Code) - Admitting close approach; not guarded by locked doors, elevation, or other effective means.
ACE - Association of Cooperative Educators
ACH - Automated clearing house. For retail customers, a choice of payment method which involves the authorized deduction of money from the individual customer's account at a financial institution for direct payment of his/her electric bill.
ACRE - Action Committee for Rural Electrification, a voluntary political action group that supports candidates for national offices.
Affidavit - As it pertains to wiring, a written declaration of work done by an electrician.
Aggregator - A broker that organizes customers into a group in order to economically purchase electricity, gas, telecommunications or other utility services.
AIC - Abbreviation for Amperes Interrupting Current. All over-current protection devices (fuses and circuit breakers) must have an interrupting rating.
AIEC- Association of Illinois Electric Cooperatives
All-requirements customer - An electric utility that purchases all of its electric power from a single supplier.
Ammeter - An instrument that measures electric current in amps.
Ampacity - The current-carrying capacity, expressed in amperes, of an electric conductor under stated thermal conditions.
Ampere - Unit of electrical current produced by one volt acting through one ohm, equal to one coulomb per second; amp.
Ampere's Law - Electric current and changing electric field create a magnetic field.
Amp-probe - Hand held tool used to measure alternating current.
APPA - American Public Power Association, a national service organization for the nation's 2,000 community owned, locally-controlled, not-for-profit electric utilities. Its members include municipalities, state power authorities, and power districts that generate, transmit, and/or distribute electric power.
Approved (National Electrical Code) - Acceptable to the authority having jurisdiction. (Check your location for the governmental authority exercising jurisdiction over application of the code.)
Arc - A flow of current across an insulated medium.
ATC - (Available Transmission Capacity) - a measurement of the capacity remaining on the transmission system at a given node or flowgate.
Automatic - Not manual. Self-acting, operating by its own mechanism when actuated by some impersonal influence, such as a change in current strength.
AWG - American Wire Gauge. The standard for measuring wire in America.
Backup power - Power that is needed when regularly used electric generating units are not in service, such as during short-term emergencies or longer unplanned outages, and during periods of scheduled maintenance when the units must be shut sown. Short-tem backup power is generally called emergency power. Long-range backup power is often provided for in reserve sharing agreements.
Balanced system - A system is said to be balanced when all phase conductors carry approximately the same current. For delta systems, this applies to two-phase conductors, and for three-phase wye systems, this applies to three-phase conductors.
Ballast - Device used to maintain current in circuit by varying resistance in response to changes in voltage.
Base load -The minimum constant level of electric demand that a utility's generating system must meet.
Base load capacity -The generating equipment normally operated to serve loads on a round-the-clock basis.
Base load plant - An electric generating plant that provides the basic power that is needed year around. A base load plant, usually housing high-efficiency steam-electric units, operates most of the hours of the year. Base load plants produce electricity at an essentially constant rate and run continuously. These units are operated to maximize system mechanical and thermal efficiency and minimize system operating costs.
Benchmarking -Comparing a company's costs, labor, performance and operating practices against the best levels of performance found outside the company.
Blackout - Period of darkness due to electric power failure.
Bonding - The electrical interconnecting of conductive parts, designed to maintain a common electrical potential.
Bond wire - Slang term used to describe what the National Electrical Code calls the equipment grounding conductor.
Branch Circuit - Within a structure, the circuit conductors between the final over-current device protecting the circuit and the outlet(s).
Breeder Reactor -While a conventional nuclear generating plant (called a converter or burner) gets its heat by splitting atoms of uranium-235, a breeder reactor (also called a fast-breeder) both burns and manufactures plutonium at the same time. A breeder reactor actually creates more fuel than it burns in creating heat. Proponents say a commercial breeder reactor, while providing hesat to generate electricity, will make enough extra plutonium to refuel itself and another breeder every 10 to 15 years.
Brownout - enforced reduction of electric power usage.
Btu - British thermal unit. The quantity of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
Bulk Marketing - Marketing electric energy and demand management, metering services, and billing services for large industrial customers.
Bulk Power - Technically, electrical power is the rate at which electricity is being produced or consumed at a specific instant in time. The supply of that electricity is bulk power to the utility, which in turn, supplies electricity to its customers.
Bulk Power Transactions -The wholesale sale, purchase, and interchange of electricity among electric utilities. Bulk power transactions are used by electric utilities for many different aspects of electric utility operations, from maintaining load to reducing costs.
Bus - A conductor or group of conductors, frequently in the form of rigid bars, that serves as a common connection for two (or more) circuits.
Bus bars - The connective parts used as the main current supplying elements of panel-boards or switchboards.
Bypass isolation switch -- A manually operated device used in conjunction with a transfer switch to provide a means of directly connected load conductors to a power source, and of disconnecting the transfer switch.
C & I -Commercial & Industrial (customers)
Cable - Strands of electrical conductor insulated from each other and laid together, often twisted around a central core. Cable may or may not have an insulated covering.
Cable jacket - A protective covering over the insulation, core, or sheath of a cable.
Candela - In reference to lighting, this is an obsolete unit of luminous intensity. Also called "candle" or "standard candle."
Capacity - 1) Also known as the power or capability of an electric generating plant. Facilities I place to serve electric customers. 2) The total amount electrical energy a power line is able to transport at any given time. Measured in kVA.
Capacitance - Measure of a capacitor's ability to store a charge.
Capacitor - A device that accumulates and holds a charge of electricity.
Capital credits - In a cooperative, capital credits are the disbursement of excess margins (what would be considered profit in an investor-owned utility). This money is shared among cooperative consumer-members, based on their patronage.
Capitalization - The total of long-term debt, preferred stock and common stock equity.
CCA - Cooperative Communicators Association
CCC - Certified Cooperative Communicator (formerly CREC - certified rural electric communicator)
CCF - A common measurement of natural gas - 100 cubic feet.
CFC - National Rural Utilities Cooperative Finance Corporation. Established in 1969 by rural electric cooperatives, CFC provides financing from the private money market for expansion and improvements by the cooperatives. Headquartered in Washington, D.C.
CRC - Cooperative Response Center
CRR - (Congestion Revenue Rights) - a financial instrument that is intended to offset in whole or in part congestion costs associated with a specific transaction. Also known as an FTR.
Charge - the basis of electric energy, manifested in current, voltage, and electric field as positive or negative element that attracts unlike and reples like charged bodies.
Circuit - A closed path through which current flows from a generator, through various components, and back to the generator.
Circuit breaker - A switching device designed to open and close a circuit by non-automatic means and that will automatically interrupt electric circuit under abnormal conditions to prevent harmful, excessive current.
Clearance - The clear distance between two objects measured surface to surface. For safety reasons, proper clearance must be maintained between power lines and the ground, buildings, trees, etc.
Closed - A circuit that permits useful current to flow.
Coal gasification - The conversion of coal to a gas that is suitable for use as a fuel.
Coal liquefaction - The conversion of coal into liquid hydrocarbons and related compounds by a process adding hydrogen to an organic compound.
Coal slurry - A process by which coal is ground fine enough to be suspended into a solution of water so that it may be transported by an underground pipeline from a place close to where it is mined to the final destination for use.
Cogeneration - The sequential or simultaneous process in which useful heat/steam is generated, used in a variety of process applications, and then directed into a turbine to generate electricity and/or mechanical work from the useful thermal energy still available for use. Examples: utilizing waste heat from industry to produce electricity, or the waste heat from electric utilities to produce steam for industry or hot water for buildings.
Coincident demand - The maximum demand places upon electric generation and distribution facilities by a combination of two or more customers at a particular moment, even though the peak demand of the individual customers occurs at different moments and the total of the peak demands would be greater.
Common grounding electrode - The national Electrical Code permits only one grounding electrode to a building or structure. When more than one electrode is installed, they must be bonded together to form a common grounding electrode.
Common use - Simultaneous use by two or more utilities of the same kind.
Conductor - A material, usually in the form of a wire, cable, or bus bar that permits electric current to flow through it easily.
Conductance - The ability of a material to carry an electric current.
Conductor impedance - All conductors have resistance, and when alternating current flows through the conductor, eddy current induced in the conductors opposes the flow of current. This increased impedance is due to alternating current and the current resistance.
Connected load - The sum of the continuous ratings or the capacities for a system, part of a system, or a customer's electric power consuming apparatus.
Contactor - An electric relay switch.
Continuity - An unbroken path.
Cooling tower - An enclosed tower that cools water by evaporating a small percentage of it into a moving stream of air.
Cooperative - A form of business that is owned and controlled by the people, called members, who use its services or buy its products.
A cooperatively owned electric utility is a group organized under the law into a utility company that will generate, transmit, and/or distribute supplies of electric energy to a specified area not being serviced by another utility. Such ventures are generally exempt from the Federal income tax laws. Most electric cooperatives have initially been financed by the U.S. Department of Agriculture's Rural Electrification Administration.
Cooperatives operate under seven Cooperative Principles, as described below:
1st Principle: Voluntary and open membership Cooperatives are voluntary organizations, open to all persons to us their services and willing to accept the responsibilities of membership, without gender, social, racial, political, or religious discrimination.
2nd Principle: Democratic member control Cooperatives are democratic organizations controlled by their members, who actively participate in setting their policies and making decisions. Men and women serving as elected representatives are accountable to the membership. In primary cooperatives, members have equal voting rights (one member, one vote) and cooperatives at other levels are organized in a democratic manner.
3rd Principle: Member economic participation Members contribute equitably to, and democratically control, the capital of their cooperative. At least part of that capital is usually the common property of the cooperative. They usually receive limited compensation, if any, on capital subscribed as a condition of membership. Members allocate surpluses for any or all of the following purposes: developing the cooperative, possibly by setting up reserves, part of which at least would be indivisible; benefiting members in proportion to their transactions with the cooperative; and supporting other activities approved by the membership.
4th Principle: Autonomy and independence Cooperatives are autonomous, self-help organizations controlled by their members. If they enter into agreements with other organizations, including governments, or raise capital from external sources, they do so on terms that ensure democratic control by their members and maintain their cooperative autonomy.
5th Principle: Education, training, and information Cooperatives provide education and training for their members, elected representatives, managers, and employees so they can contribute effectively to the development of their cooperatives. They inform the general public - particularly young people and opinion leaders - about the nature and benefits of cooperation.
6th Principle: Cooperation among cooperatives Cooperatives serve their members most effectively and strengthen the cooperative movement by working together through local, national, regional, and international structures.
7th Principle: Concern for community while focusing on member needs, cooperatives work for the sustainable development of their communities through policies accepted by their members.
Six principles have guided cooperatives for the past 30 years. The number of principles increased to seven as the result of a vote taken by the General Assembly of the International Cooperative Alliance in Manchester, England, on September 23, 1995. The goal of the new principles is to better reflect the needs of cooperative members in today's society.
COP - Coefficient of Performance. A measurement of a heat pump in the heating mode. The ratio of how much heat energy that is moved compared to how much energy in consumed in moving it.
Corrosion - The deterioration of a substance (usually metal) because of reaction with its environment. Example: some soil conditions have a corrosive effect on underground electrical cable.
Coulomb - The quantity of charge transferred by one ampere in one second between two points in a circuit.
Current - The rate of flow of electrons, measured in amperes.
Current rating - The amount of electrical current flow a device has been designed to withstand.
Cutout - An assembly of a fuse support with either a fuse holder, fuse carrier, or disconnecting blade. A fuse holder or fuse carrier may include a conducting element (fuse link), or may act as the disconnecting blade by the inclusion of a non-fusible member.
CWIP - Construction work in progress.
DMA - Dairyland Managers Association
DC - Direct current. Electricity flowing continuously in one direction and has virtually invariable magnitude, as opposed to alternating current, which changes direction frequently. Current produced by a battery.
Declining rate - An electrical rate structure which charges a lower rate per kilowatt-hour as consumption increases.
De-energized - Free from any electrical connection to a source of potential difference and from electric charge; not having a potential different from that of the earth.
Degree Day - A measure of the deviation of the mean daily temperature from a given standard, with each variance from the standard during a single day recorded as one degree day. Used to estimate energy requirements for heating a building.
Demand - Refers to the maximum rate at which a customer takes energy from the electric system. A customer with a load of 10 kilowatts makes a demand or takes energy at a rate of 10 kilowatt-hours per hour.
By their very nature as utilities serving the public, every electric system is subject to a constantly fluctuating customer demand for electricity. The demand, or load, on the system varies from hour to hour, day to day, and season to season. The demand, which is expressed in kilowatts (kW), is a measure of the rate of electric usage. Seasonal demands are affected by the number of hours of daylight, temperature extremes, and activities such as industrial or agricultural processes.
Demand charge - A component to the electric rates paid by wholesale customers and large retail customers. The demand charge is based on the individual customer's maximum demand occurring on the utility system, within a set time frame.
Demand factor - The ratio of the maximum demand of an electrical system, or part of that system, to the total connected load of an electrical system or the part of that system under consideration.
Demand interval - The time period during which flow of electricity is usually assessed in: 15, 30 or 60 minute increments.
Demand-side management - managing electric demand with programs that help customers use energy more efficiently or shift usage to non-peak times, reducing the need for additional generation supply.
Density - Average number of consumers per mile of power line.
DER (Distributed Energy Resources) - Same as distributed resources, refers to any small generator installed to serve a specific load, or loads within a small, confined area.
Dielectric - A nonconductor of electricity. The property of an insulating material for opposing electrical fields.
DISCO - DISCO= LINECO + RETAILCO. In addition to constructing, operating, and maintaining the distribution wires, a DISCO also provides value-added services and has direct contract/responsibility for customer service.
Disconnect - 1) A switch used to disconnect an electrical circuit or load from the conductors that supply power. 2) To shut off the current to a customer's premises by removing its connection with the utility distribution system.
Disconnecting or isolating switch - A mechanical switching device used for changing the connections in a circuit, or for isolating a circuit or equipment from a source of power.
Discovery request - Attorneys for one party in a rate case, or other legal proceeding, ask the other parties for information (such as rate studies, income tax returns and a wide range of other matters).
Dispatching - The operating control of an integrated electric system involving such operations as the assignment of load to specific generating stations to result in the most reliable and economical use of fuel supply. Also, the control of operations and maintenance of high voltage lines, substations and equipment, the operation of principal tie lines and switching, and the schedule of energy transactions with other connecting electric utilities.
Distribution - The facilities and equipment that permit delivery of electric power to a consumer through intermediate or low-voltage (7,200 KVA) power lines. Distribution cooperatives electric retail electricity. Wholesale electric energy is supplied to distribution cooperatives by a generation and transmission (G & T) source, such as the Dairyland Power Cooperative.
Distribution cooperative - An organization that purchases wholesale power from its G & T or nearby investor-owned utility and delivers it at cost to consumer-members.
Distribution line - That part of the electrical supply system that distributed electricity at medium voltage from a transformer substation to transformers or other step-down devices service customer premises, which finally supply power at the voltage required for customer use.
Distribution system - The portion of the transmission and facilities of an electric system off the bulk power system that is dedicated to delivering electric energy to an end-user.
Diversity - The effect of various types of electrical load on a utility system's total demand for electricity. Loads which create demand at different times allow for more efficient use of available generating capacity.
Diversity Interchange - Occurs when interconnected utilities experience peak loads at different times.
DOE - Department of Energy
DPC - Dairyland Power Cooperative
Drip-loop - An intentional sag placed in conductors that connect to overhead conductors; the drip loop will prevent rainwater from entering the weatherhead.
DSC - Debt Service Coverage. Patronage capital and margins, plus depreciation and amortization expense, plus interest expense, divided by long-term debt service.
Dual Fuel - A program for home heating that utilizes two heating sources. Electricity, at a special incentive rate, is used during off-peak hours, while an alternate fuel source is used during hours of peak electrical demand.
EER - Energy Efficiency Ratio. The ratio of cooling capacity (output) in Btu divided by power input in watts. Expressed as Btu/watt. The higher the EER number, the more efficient the unit.
Easement - A right purchased from property owners that allows utility companies to construct, operate, maintain and control facilities such as transmission and distribution lines located on their property.
ECAR - East Central Area Reliability Coordination Agreement. A regional electric reliability council area consisting of part of Pennsylvania, lower Michigan, Indiana, Ohio, part of Maryland, West Virginia, part of Virginia, and part of Kentucky.
Economic dispatch - Determines the share of the minute-by-minute load demand that each committed unit has, so that the overall system operating cost is minimized.
Ecowatts - An umbrella term for substituting electricity for conventional fossil fuels in a wide range of transportation and industrial uses, in order to obtain net energy savings and environmental gains.
Effectively grounded - Intentionally connected to earth through a ground connection or connections of sufficiently low impedance and having sufficient current-carrying capacity to prevent the buildup of voltages that may result in undue hazard to connected equipment or to persons.
EIA - The Energy information Administration. An independent agency within the US Department of Energy that develops surveys, collects energy data and analyzes and models energy issues.
Electrical continuity - An unbroken low-impedance path through which electrons flow.
Electric Broker - An entity which matches up producers of electricity with customers. Does not take ownership of or financial position in the transaction.
Electrician - A specialist in the installation, maintenance, and repair of electrical equipment. Electrical work performed at a customer's premises should be done only by a competent electrician. Check with your local municipality for any additional certification requirements needed in your area.
Electricity brokers - Independent agents that buy and sell electrical energy. May also include power marketers or "aggregators" who sell large blocks of energy to big industrial or commercial customers.
Electricity merchant - Term used with the advent of electric utility restructuring to denote an entity which provides electricity and serves to wholesale and retail customers.
Electric marketer - An entity which purchases and resells electric energy and capacity to customers. Assumes ownership of the electric energy and/or capacity.
Electric rate schedule - A statement of the electric rate and the terms and conditions governing its application, including attendant contract terms and conditions that have been accepted by a regulatory body with appropriate oversight authority.
Electrocution - Death caused by electrical current through the heart, usually over 50 milliamperes.
Electron - Negatively charged particle in all atoms that is the basis of electricity.
Embedded cost - In the operation of utilities, monies already spent for investment in plant and for operating expenses or committed for long-term purposes.
EMF - Electromotive force. Potential difference, expressed in volts, between terminals of a source of electric energy.
EMS (Energy Management System) - An advanced computer system that does all sorts of neat stuff.
Energy - Delivered power measured in kilowatt-hours (kWh).
Energy Policy Act - A 1992 federal statute that, among other things, partially opens the electric power industry into a competitive marketplace by removing some barriers.
Energized - Electrically connected to a source of potential difference, or electrically charged so as to have a potential significantly different from that of earth in the vicinity. Syn: live; hot
Enclosure - The case or housing around electrical apparatus, or the fence or walls surrounding an electrical equipment installation, the purpose of which is to prevent persons from accidentally contacting energized parts, or to protect the equipment from physical damage. For public safety, please immediately report any unsecured or damaged enclosures to the utility. Example: underground transformer casing.
Energy Service Company (ESCO) - Term used with the advent of electric utility restructuring to denote a company which markets and provides energy-related products and services.
Environmental Impact Statement (ESI) - A statement based on detailed study that sets forth the probable environmental consequences of building and operating large scale power facilities.
EPA - Environmental Protection Agency. A federal agency that develops rules and regulations concerning environmental protection and monitors utilities and other industries.
EPRI - Electric Power Research Institute, an organization financed by electric utilities for the purposes of research and development of energy resources.
ERCOT - Electric Reliability Council of Texas. A regional electric reliability council covering most of Texas.
ESCO - An energy services company. Example: EnPower Services, Inc.
ETS heating - Electric thermal storage; a type of heating that utilizes off-peak electric energy to store heat energy in a medium such as special high-density brick.
FCA (Fuel Clause Adjustment) - A utility company's rates are set to recover various costs: administrative expenses, cost of plant, fuel costs and others. Of these, fuel costs are the most variable and can change markedly from month to month. To avoid having a new rate case every time fuel costs fluctuate, regulatory commissions grant to the utilities fuel clauses in addition to their regular (base) rates. The regular rates contain a certain amount for basic fuel expenses. The fuel clause, on the other hand, rises or falls from the basic fuel expense level depending on increases or decreases in the price of fuel burned.
Federal Energy Regulatory Commission (FERC) - A federal agency created in 1977 to regulate, among other things, interstate wholesale electric rates, transmission pricing and hydroelectric licensing. Formerly the Federal Power Commission.
Feeder - Slang Electrical distribution line.
Filed tariff - Rates and rules filed with the Federal Energy Regulatory Commission.
Firm energy - The amount of electric energy that is certain to be available at all times from any given plant or system, or under any given contract even under adverse conditions such as when a given power plant is out of service.
Fission -The process whereby the nucleus of an appropriate type, after capturing a neutron, splits into (generally) two nuclei of lighter elements, with the release of substantial amounts of energy and two or more neutrons.
Fixed costs - Annual costs attached to the ownership of property such as depreciation, taxes, interest and insurance.
Flat rate - A one-part electrical rate wherein a utility's revenue requirements are lumped and consumers pay the same rate for each kilowatt-hour of electricity used, regardless of the demand they place on the system or their individual load factor.
Flowgate - A point or combination of points where electrical flow is measured on the grid.
Foot-candle - The illumination of a surface one foot distant from a source of one candela, equal to one lumen per square foot. Also called "candle-foot."
Fossil fuel -Fuels such as coal, oil and natural gas, which are derived from the earth and burned for heat energy. Also called conventional fuels. Alternatives include hydro (water), solar (sun), nuclear, wind, geothermal (derived from heat contained deep inside the earth) and other energy sources.
FTR (Financial Transmission Rights) - see CRR.
Fuel - Anything consumed to produce energy. Conventional fuels (coal, oil, natural gas, wood); hydro (water), solar (sun), nuclear, wind, geothermal (derived from heat contained in earth).
Fuel (power adjustment) clause - Utility rates are set to recover various costs. Of these costs, fuel costs are the most variable and can change markedly from month to month. To avoid having a new rate case every time fuel costs fluctuate, regulatory commissions grant to the utilities fuel clauses in addition to their regular (base) rates. The regular rates contain a certain amount for basic fuel expenses. The fuel clause, on the other hand, rises or falls from the basic fuel expense level, depending on increases or decreases in the price of fuel burned.
Functional Segmentation or Unbundling - Separation of the vertically integrated functions of utility companies into generation, transmission, distribution and energy services.
Fusion - The formation of a heavier nucleus from two lighter ones with a release of energy in the process.
G & T- Generation and transmission. In the case of the An electric cooperative distribution system, electric energy is produced by a G & T cooperative known as Dairyland Power Cooperative.
GENCO - A generating company maintaining and operating new and existing power plants.
Generating station - A plant wherein electric energy is produced by conversion from some other form of energy.
Generation - production or the means of producing power.
GEN~SYS - A strategic alliance of the generating resources and power marketing activities of Dairyland Power Cooperative (DPC) of La Crosse, Wisconsin and Cooperative Power (CP) of Eden Prairie, Minnesota. Formed on January 1, 1996. In 1999, Dairyland Power acquired CP's interest in GEN~SYS Energy. This strong energy services marketing organization provides the means to respond to the competitive power markets including services of value to its customers.
GEN`SYS energy is incorporated in Minnesota as a cooperative corporation. It is a member of the Mid-Continent Area Power Pool (MAPP) and is authorized by the Federal Energy Regulatory Commission (FERC) to transact at market based rates.
Geothermal energy - Energy from the internal heat of the earth.
Gigawatt - One million kilowatts (one billion Watts).
G. O. (General Order) - A regulation issued by the Public Service Commission.
Grid - A system of high-voltage transmission and power-generating facilities that is interconnected with a number of other bulk power supply agencies on a regional basis. A grid enables power to be transmitted from areas having a surplus to areas experiencing a shortage. A grid also eliminates some duplication of costly facilities in a given region.
Grid-wide pricing - Pricing independent of distance traveled. Price to transmit from any one point to any other point on the grid is the same.
Green Power - Electricity that is generated exclusively from environmentally safe energy sources (solar, wind, tidal, geothermal, biomass and other sources).
Ground - A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth.
Grounded conductor - (1) A system or circuit that is intentionally grounded. (2) A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes.
Grounded - Connected to or in contact with earth or connected to some extended conductive body that serves instead of the earth.
Ground-fault - A connection (electrically conductive) between any of the conductors of the electrical system and any object that is grounded. During the period of a ground-fault, dangerous voltages and currents exist and must be cleared.
Ground-Fault Circuit Interrupter (GFCI) - A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds some predetermined value that is less than that required to operate the over-current protective device of the supply circuit. GFCI should be used in locations where water or dampness is likely to be present, such as in kitchens, bathrooms, garages, laundry rooms, work shops, agricultural buildings and outside electrical outlets.
Ground-Fault Protection of Equipment - A system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all underground conductors of the faulted circuit. This protection is provided at current levels less than those required to protect conductors from damage through the operation of a supply circuit over-current device.
Guy - A tension wire that adds strength to an electrical pole.
Harmonic - An oscillation whose frequency is a multiple of the normal frequency. Example: Third harmonic is equal to 180 hertz, since normal frequency in the US is 60 Hz.
Head - The depth of water in a hydroelectric plant reservoir that is above the level of the plant's turbines. High heads (those of more than 65 feet) are more feasible producers than low heads, because they provide more water pressure with which to produce power.
Heating element - Low resistance wire that heats when current flows through it.
Hertz - International unit of frequency, equal to one cycle per second of alternating current, abbreviated as Hz.
Horsepower - Measure of the time rate of doing work, equal to 745.7 watts or 33,000 foot-pounds per minute, abbreviated as Hp.
Hot leg - A conductor that normally operates at a voltage above ground.
Hydroelectric or Hydropower - Electricity generated with moving water being its energy source.
IAEC - Iowa Association of Electric Cooperatives
IBEW - International Brotherhood of Electric Workers
IEEE- The Institute of Electrical and Electronics Engineers, Inc. The IEE develops standards and definitions, test methods, symbols, units, and safety in the field of electrical science and engineering.
IMEA - Illinois Municipal Energy Agency
Impedance - (symbol: Z) A measure (in ohms) of the response of an electric circuit to an alternating current. The total opposition to current flow due to capacitance, inductance, and resistance. Low impedance is important for the grounding system, so that it will carry fault current to trip the over-current protection device. High impedance will reduce the fault current flow, resulting in slowing down or eliminating the opening of the circuit protection.
Inductance - The flux in a magnetic field caused by changing current in an electric circuit or device, inducing voltage in that circuit or a nearby circuit.
Induction - A process by which electrification, magnetization, or electromotive force is produced in bodies and circuits through proximity to a charge or field.
Inductor - Loop or loops of conducting material that produces an oriented magnetic fields when current is passed through it.
Inrush current - The initial current when an electric coil or motor is energized. Often the initial current is equal to six times the normal current.
Insulation - A material that prevents electrical current from escaping or entering where it is not wanted, used especially to electrically isolate two conductive surfaces.
Insulator - A nonconductor, usually of glass or porcelain, used for insulating and supporting electric wires.
Integrated circuit - IC; electronic circuit conducted on a single semiconductor wafer or microchip.
Interchange agreement - An agreement that can include a variety of services utilities provide each other to increase reliability and efficiency, and to avoid duplicating expenses. Some examples are: transmission service (the use of transmission lines to move power from one area to another); emergency services (an agreement by one utility to furnish another with power to protect it in times of emergency, such as a power plant breakdown); reserve sharing (when utilities contribute to a common pool of generating plant reserves so each individual utility's reserves can be reduced); and economic exchanges (when utilities swap power out of various plants to avoid running their most fuel expensive units).
Interconnection - Two or more electric systems having a common transmission line that permits a flow of energy between them. The physical connection of the electric power transmission facilities allows for the sale or exchange of energy. The major electric networks which span and link the US and parts of Canada and Mexico for the purpose of transporting electric power.
Interconnection agreement -An agreement between two utilities to connect their transmission systems. Once interconnected, the utilities may enter into interchange agreements.
Intermediate unit - An electrical generation unit that is less economical than a base unit, but more economical than a peaking unit.
Internet - A public network of computer networks, spanning the world, linking your computer to others. It involves formatted pages of text and images, electronic mail and newsgroups.
Independent System Operator (ISO) - A separate entity created to operate, control and ensure the integrity of the integrated transmission grid independently of any generation, wholesale or retail market.
Inverted rate - An electrical rate structure which would reverse pricing in declining block rates by charging a higher rate per kilowatt-hour as consumption increases.
Investor-owned Utilities (IOU)- Publicly traded utility companies which are privately owned by stockholders for the purpose of making profit.
Insulator- A process or material that prevents or reduces the flow of electricity, heat, or sound from one place to another.
Interrupting rating- The highest short circuit current at a rated voltage that a device is intended to interrupt under standard test conditions.
IPP - Independent Power Producer or "nonutility generator" - The Public Utilities Regulatory Policies Act of 1978 (PURPA facilitated the creation of these small - less than 80 megawatts of capacity - electric generators that were exempt from many state and federal regulations.
ITC (Independent Transmission Company) - An organization that either owns or has contractual rights to transmission facilities within a specific region, and that meets FERC-specified criteria for independence. An ITC's primary purpose would be the development and operation of transmission.
ITP (Independent Transmission Provider) - A public utility defined in FERC's SMD NOPR that meets certain characteristics and provides certain required services related to the operation of a transmission system.
Jacket - A protective covering over the insulation, core, or sheath of an electrical cable.
Joint use - Simultaneous use by two or more kinds of utilities. This can be done by attachments to poles or through plowing underground cable of various types (example: electrical and telephone service) in at the same time, using the same right-of-way corridor.
Joule - A unit of work and energy. (symbol J) It is defined as the work done (energy transferred) in one second by a current of one ampere at a potential difference of one volt. One watt is equal to one joule per second.
Junction box - An enclosure for the connection or branching of one or more electrical circuits.
Kilovolts (kV) - Specifies the amount of electric force carried through a high voltage transmission line.
In the United States, the standard voltage for use in the home is 120 volts. For long transmission purposes, the voltages go as high as 230,000 volts, or even 1,000,000 volts. Sometimes these high voltages are expressed in kilovolts, a kilovolt being equal to 1,000 volts. A 230,000 volt line would be called a 230 kilovolt line.
Kilowatt (kW) - A unit of power or capacity. The basic measure of electric power demand, kilowatt stands for 1,000 Watts. It is the product of volts and amperes of resistive loads divided by 1,000.
A kWh is equal to one kW of power supplied for one hour. A 100-watt light bulb burned for 10 hours uses 1 kWh. One thousand kWs is a megawatt (MW). One thousand kWhs is a megawatt-hours (MWh).
Kilowatt-hour (kWh) - The basic measure of electric energy required to operate a 100-Watt light bulb for 10 hours. On a retail customer's billing statement, the site's electric consumption is expressed in kilowatt-hours.
KVA - Kilovolt-ampere; the product of volts and ampere divided by 1,000.
LACBWR - La Crosse Boiling Water Reactor. Discontinued operation on April 30, 1987.
Leg - A trade name to describe an ungrounded (hot) conductor.
Lifeline rate - An electrical rate structure for residential customers, which is designed with an artificially low first block. Revenue deficiencies created in establishing this low first block are made up by increased rates outside the block (and within the consumer class), and in commercial and industrial classes. In some cases, the rate is used in reference to electrical service for the elderly or those in low- and fixed-income brackets.
Lightning arrestor - A device that protects equipment from the destructive effects of lightning surges that strike power lines and antennas during electrical storms, by discharging or bypassing the surges.
Limit switch - A mechanically operated device that stops a motor from revolving, or reverses it, when certain limits have been reached.
LINECO - An entity which constructs, operates, and maintains the distribution wires in a utility system. Subject to the state Public Service Commission.
Line loss - Electric energy lost in the process of transmitting it over power lines.
Line transformer or Distribution transformer - This device changes the voltage from the primary distribution voltage to the secondary distribution voltage required by the power customer.
Lines (electrical supply) - Those conductors used to transmit or deliver electric energy and their necessary support or containing structures.
Line side and load side - The line side is the supply side of any equipment, such as the power to the switch. The load side is the conductors leaving a switch. When referring to services, the line side is referred to as the supply side.
Live - Energized. A shock hazard exists.
Live parts - Electric conductors, buses, terminals, or components that are uninsulated or exposed and a shock hazard exists.
LMP (Locational Marginal Pricing) - A method of transmission pricing that takes into consideration system congestion in determination of the marginal price of generation within a given pricing zone.
Load - (1)A device, or resistance of a device, to which power is delivered in a circuit. (2) The measure of electrical demand placed on an electric system at any given time. See demand.
Load curve - A graph used to show how the use of electricity (demand) rises and falls during a given period of time.
Load factor - The ratio of average demand to peak demand. It is a measure of efficiency that tells whether a system's electrical usage is reasonably stable or if it has extreme peaks and valleys. A high load factor is better than a low load factor, because it may result in a lower average price per kilowatt-hour.
Load forecasting - The methods used in determining a system's short and long-term growth in peak load and kilowatt-hour sales by consumers.
Load leveling - Any practices which increase baseload generation. Peak load pricing and time-of-day charges are two techniques that electric utilities use to reduce peak load and to maximize efficiency in the generation of electricity.
Load management program - A program by which an electric system seeks to control its customers' use of electricity, or loads, in order to reduce the system's total demand at a time of maximum (peak) usage. Load management can involve such techniques as voltage reduction, cutting off water heaters or electric storage heating units for short periods of time by a remote control device, controlling the time irrigation pumps run, and the like.
Load side and line side - The load side is the conductors leaving a switch. The line side is the supply side of any equipment, such as the power to the switch. When referring to services, the line side is referred to as the supply side.
Local Distribution Company (LDC ) - A business that owns, operates, constructs and maintains distribution facilities.
Loop transmission system - A system in which alternate transmission lines can deliver electric power to an area. Used to enhance system reliability.
Lug - A terminal device for terminating a conductor.
Luminaire - A complete lighting unit consisting of lamp or lamps, together designed to distribute light.
Lumen - The amount of light passing through an area per second. The lumen is defined in terms of the light falling on a unit area at a unit distance from a liht source of luminous intensity of one candela.
M & S - Materials and supplies.
MAAC - Mid-Atlantic Area Council. A regional electric reliability council similar to MAPP, but serving part of Pennsylvania, New Jersey, part of Maryland and Delaware.
MAC - Minnesota Association of Cooperatives
MAIN - Mid-America Interconnected Network. A power pool similar to MAPP, but serving a different region. The area served covers the eastern half of Wisconsin, Illinois and some of Indiana.
MAPP - Mid-continent Area Power Pool, a regional association of more than 90 electric utilities (including Dairyland Power Cooperative) and other electric industry participants serving the following states and provinces: Minnesota, Iowa, Nebraska, North Dakota, and Manitoba and portions of Missouri, Kansas, Wisconsin, Montana and South Dakota. Its three functions are to: ensure that electricity is transmitted in a reliable fashion throughout the region, help facilitate the voluntary wholesale buying and selling of bulk power, and oversee transmission service within and adjacent tot he MAPP region to make sure service is provided in a comparable and efficient manner.
Marginal cost - The change in total costs associated with an unit change in quantity supplied (i.e., demand or energy).
Marginal-cost pricing - Pricing at the cost of producing the next unit of the goods.
Marginal price - The payment required to obtain one additional unit of a product.
Market power - Anti-competitive influence on price or supply by one or a few providers; control of the generation and/or transmission entities.
Maximum demand - The highest average use of electricity by a customer during a specified period (usually 15 minutes or 30 minutes). For large amount of power, the unit of time for measuring the demand is sometimes one hour.
Maximum drawdown - A term used in connection with hydroelectric plant sites, it means the lowest reservoir level that would occur during the most critical dry period. (See Head).
Megawatt (Mw) - One million Watts, or 1,000 kilowatts.
Megawatt-hour (Mwh) - One thousand times more than a kilowatt-hour, or 1,000 kwhs.
Member - In an electric cooperative, the customers are referred to as "members" because they share in the benefits and responsibilities of joint ownership.
Microchip - A tiny electronic integrated circuit.
Mill - One tenth of a cent, a common utility industry monetary measure.
MISO (Midwest Independent Transmission System Operator) - The first RTO to be officially recognized by FERC, operating transmission in the Midwest from the Dakotas to Ohio. Headquartered in Carmel, Indiana.
Modulation - Alteration in waveform frequency or amplitude due to superimposition of another wave or signal.
Motor - A device that transforms electric energy into mechanical energy, especially one that produces motion by means of a coil of wire around armature turning between poles of a magnet.
Motor Control Center - An assembly of one or more enclosed sections having a common power bus and principally containing motor control units.
MREA - 1.) Minnesota Rural Electric Association; 2.) Midwest Renewable Energy Association
Municipals - A term that refers to municipalities that have their own electrical generating and distribution systems and/or that purchase electricity at wholesale from another electrical supplier.
Mutual inductance - Interactive inductance between inductive circuit elements.
NAERO (North American Electric Reliability Organization) - A reformulated NERC that has enforcement authority in addition to the responsibility for developing and implementing reliability standards. NERC has revised its organization in anticipation of becoming NAERO, but still does not have the authority (which will come through an act of Congress) to enforce its standards.
NAESB (North American Energy Standards Board) - Originally the Gas Industry Standards Board (GISB), this organization has expanded its function to include the development of communications and business standards for the electric industry.
Nameplate rating - The rated capacity of a generator or other piece of equipment, under conditions specified by the manufacturer and usually indicated on a nameplate attached to the unit.
NEC- National Electrical Code. The purpose of the Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
NERC - North American Electric Reliability Council. The reliability council's goal is to promote the reliability of the bulk electric systems in North America through cooperation and coordination.
NESC - National Electrical Safety Code (recognized as an American National Standard)
Neutral Conductor - Grounded Conductor (not to be confused with the grounding conductor), this conductor permits the use of line to neutral loads (120 and 277 volt loads), will serve as a current-carrying conductor to carry any unbalanced currents and provide a low impedance path for the flow of fault current to facilitate the operation of the over-current protective devices. During a ground-fault condition, dangerous voltage (potential) exists, and it is very important to clear this fault in the shortest practical period of time. The grounded conductor is used to assist in the clearing of fault current.
Nipple - Conduit pipe less than two feet in length. It does not have to be straight.
Node - A given point on the transmission system recognized by a transmission provider and/or reliability organization. Often associated with a generator or other major facility on the grid.
Noise - More technically referred to as Electro-Magnetic Interference (EMI) and Radio Frequency Interference (RFI), electrical noise disrupts the smooth sine wave one expects from utility power.
Nonautomatic - Action requiring personal intervention for its control. As applied to an electric controller, nonautomatic control does not necessarily imply a manual controller, but only that personal intervention is necessary.
Noncoincident demand - the sum of the individual peak demands placed on generation and distribution facilities by a combination of two or more customers.
Nonincendive circuit - A circuit, other than field wiring, in which any arc or thermal effect produced under intended operating conditions of the equipment, is not capable, under specified test conditions, of igniting the flammable gas-, vapor-, or dust-air mixture.
Nonincendive field wiring - Wiring that enters or leaves an equipment enclosure and, under normal operating conditions of the equipment, is not capable, due to arcing or thermal effects, of igniting the flammable gas-, vapor-, or dust-air mixture. Normal operation includes opening, shorting, or grounding the field wiring.
Nonlinear load - A load where the wave shape of the steady-state current does not follow the wave shape of the applied voltage.
NOPR - Notice of Proposed Rulemaking (see FERC).
NPCC - Northeast Power Pool Coordinating Council. A regional electric reliability council area consisting of Maine, Vermont, New Hampshire, Massachusetts, New York, Connecticut and Rhode Island.
NRC - Nuclear Regulatory Commission, the federal agency responsible for the licensing and safety of nuclear power plants.
NRECA - National Rural Electric Cooperative Association. A national service organization of electric cooperatives that is headquartered in Arlington, VA.
NRTC - National Rural Telecommunications Cooperative, Washington, DC NRTC is a national satellite-based services cooperative jointly formed in 1986 by NRECA and CFC. NRTC is owned and controlled by the nation's rural electric and rural telephone systems. It has developed telecommunications and educational services for consumer-members and rural utility business applications.
O & M - Operation and maintenance expenses. By far, in an electric utility, the largest part of O & M is fuel expenses used in the production of electricity. Other elements that make up the O & M total are transmission and distribution.
OASIS (Open Access Same-time Information System) - An internet-based system that allows all authorized parties access to information about any given transmission system on a comparable basis.
Off-peak power - Power supplied during designated periods of relatively low system demand.
Ohm - A unit of resistance; a resistance of one ohm sustains a current of one ampere when one volt is applied across the resistance.
Ohm's Law - Current is directly proportional to applied voltage, and inversely proportional to resistance, reactance, or impedance.
Oil circuit reclosure - A cutout in which all or part of the fuse support and its fuse link or disconnecting blade is mounted in oil with complete immersion of the contacts and the fusible portion of the conducting element (fuse link) so that arc interruption by severing of the fuse link or by opening of the contact will occur under oil.
On line - Term generally used to indicate when a generating plant is scheduled to be in operation. When an operational plant is not on line, it is said to be "down."
On-peak -Power supplied during designated periods of relatively high system demands.
Open - A discontinuous circuit that does not permit useful current flow.
Oscilloscope - An instrument that uses a cathode-ray tube to display waveform images of periodic changes in voltage or current.
Ought sizes - An expression referring to conductor sizes No. 1/0, 2/0, 3/0, and 4/0.
Outage - interruption of service to an electric consumer.
Outlet - An electric receptacle that leads to the power source, into which electric devices are plugged.
Over-current - Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.
Overload - Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or ground fault, is not an overload.
Overload protection - A device that opens as a result of excessive current, but not short circuit or ground-fault current. A current that is not more than six times the rated current for alternating current motors.
Pad-mounted equipment- A general term describing enclosed equipment, the exterior of which enclosure is at ground potential, positioned on a surface-mounted pad. Example: underground transformers and junction boxes.
Pancaking of rates- 1) When a utility places a new wholesale or retail rate increase into effect on top of an older rate increase that has not yet received final approval by the proper government agency. 2) Refers to the accumulation of transmission payments to multiple transmission owners as electricity crosses from one transmission line to another.
Parallel- Connections of two or more devices between the same two terminals in a circuit.
Parallel circuit- An electrical circuit that has more than one path for current flow. A parallel circuit has positive and negative terminals connected to two distinct points, with voltage applied equally throughout.
Parallel path flow- The capacity of power lines hundred of miles away from an individual transaction, using the interconnected system, to carry a part of the power being transferred between two utilities.
Partial-requirement customer- An electric system that purchases only part of its electric power from a single utility. Additional power requirements are met by generating electricity itself, or by purchasing it from a separate supplier.
Patronage dividends- The margins, or "profits," of an electric cooperative are returned to the consumer-members in the form of patronage dividends. The money is allocated annually by the cooperative into individual member accounts on the basis of their patronage (amount of money paid for electricity) during the year.
PCA - Power Cost Adjustment. The difference in wholesale power costs from the costs allowed for the cooperative's rate base.
Peak alert - A load management program that encourages retail consumers to avoid spread out their use of electricity and defer any unnecessary use of electricity until times when the system demand is lower.
Peak demand - The maximum amounts of electricity used by a utility customer at any given time during the year. The peak is used to measure the amount of electric transmission, distribution, and generating capacity required to meet that maximum demand, even if it occurs infrequently and only for very short durations.
Peaking unit - Electric generation units or stations which are available to assist in meeting that portion of peak load which is above base load.
Peak load - The greatest amount of electricity used during a time period by the consumers in a utility's system.
Peak-load pricing - A pricing system that charges a customer a higher rate for electricity used during the utility system's maximum (peak) demand, and a lower rate for power used at times of lower, or off-peak demand.
Peaking plant - A power plant that may be operated only at times necessary to help meet a utility's maximum peak demand.
Period - The time required for one waveform cycle to be completed; inverse of frequency.
Phase - A stage in oscillatory motion, such as a wave motion: two waves are in phase when their peaks and their troughs coincide. Otherwise, there is phase difference, which has consequences in interference phenomena and alternating current electricity.
Phase leg - One of the phase conductors (ungrounded, hot conductor) of an electrical system.
Phase shift - The time difference between waveforms.
Photoelectric cell - A cell whose electrical properties are modified by illumination by light
Photovoltaic - The process by which radiant (solar) energy is converted directly into electrical energy using a solar cell.
Plenum - A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.
Plug - A fitting inserted into a receptacle to establish contact connection in a circuit.
Plug, three-pin - An insulated device with three metal projections used to connect the wires in the cable of an electrical appliance with the wires of a main supply socket.
Pondage - The amount of usable water storage at a hydroelectric site.
Polarity - Distinguishing one conductor or terminal from another. Identifying how devices are to be connected, such as + or -.
POOLCO - A regional energy wholesale market where buyers and sellers can talk to each other and buy and sell electricity. It coordinates the movement of power from where it is generated to where it is needed, including the dispatch of pool member power plants. Subject to FERC jurisdiction.
Pooling - An arrangement between two or more utilities so that, in meeting their combine loads, the most economic and efficient use can be made of their combined power supplies.
Potential - Work needed to bring a unit of positive charge from distance to given point.
Potential difference - The difference in electric force between any two points in a circuit, with current flowing from high to low level.
Power - The time rate of electric energy in a device or circuit, measured in watts.
Power broker - An entity which matches power buyers with sellers, however does not take title to the energy being transacted.
Power factor - A measurement of efficiency in the use of electricity. For example: a 100% power factor would be like a horse pulling a wagon on rails directly forward with no resistance. If the horse turns and pulls at a right angle to the rails, he may pull just as hard, but his efforts will not move the car. This would be a zero percent power factor. Now, if he pulls at a 45 degree angle to the rails, he will pull the car, but not with as high an efficiency as if he were pulling straight down the rails. In the use of electricity, not every kilowatt generated translates into equivalent horsepower efficiency.
Power grid - A network of generation, transmission and distribution system that are interconnected.
Power marketer - An entity which matches buyers with sellers and also takes title to the electric energy before its resale.
Power pool - An association of two or more interconnected electric utilities planned and operated to supply power in the most reliable and economical manner for their combined load requirements and maintenance program. Depending upon the degree of control authorized by the member utilities, these pools may be run under a single system dispatch to supply power to meet combined load requirements and maintenance programs, or just share the benefits of planned or hourly available wholesale sales of power and energy among the member utilities.
Power quality - The extent to which a utility system is able to maintain its delivery of electric energy within the tolerable limits of voltage and without outages or other problems with affect a customer's equipment use.
Power supply - Source of current and voltage.
Price squeeze - A situation in which companies charge some customers a higher rate for wholesale power than the rate charged some or all of their retail customers, thereby preventing competitive retail rates in similar rate classifications between the wholesale customers.
Primary - Normally referring to the part of a device or equipment connected to the power supply circuit. Example: customer's side of the electric meter would be considered secondary wiring.
Publicly Owned Electric Utility - A class of ownership found in the electric power industry. This group includes those utilities operated by municipalities, and State and Federal power agencies.
PUC - Public Utility Commission
Pumped storage - Electricity that is generated at times of low demand (by equipment that would otherwise be idle) is used to pump water from a lower reservoir into a higher reservoir. Then, during times of peak demand, the water is used to run a hydroelectric generating plant.
PURPA - Public Utility Regulatory Policy Act. One of five parts of the National Energy Act passed by Congress on October 15, 1978. It is concerned with voluntary rate standards, cogeneration, small hydro loans, interconnections and wheeling, and other regulatory policies.
Push-button - A manually operable plunger or button for closing or opening a set of contacts. According to the National Electrical Code, a push button is not considered a disconnect or controller.
Quad- A quadrillion Btus. The energy contained in eight billion gallons of gasoline.
Raceway - Any channel designed expressly and used solely for holding conductors.
Rachet - A clause in a rate schedule that provides that maximum past or present demands be taken into account in establishing billings for previous or subsequent periods. The wholesale electrical supplier has the rachet clause in a rate schedule to finance enough generating capacity to meet the demands by the wholesale customer(s). The costs for installing and maintaining that generation capacity must be paid for, even during months when it is not entirely used to supply the wholesale customer(s).
Radio receiver control - A device that, on receiving an operating signal via radio waves, is used to connect equipment to or disconnect equipment from the electric power supply. Used in load management programs on such things as water heaters, heating and air conditioning units.
Rate base - A utility's rate base is the total value of its various properties: power plants, transmission lines, buildings, fuel, etc. The utility, through its rates, collects a percentage of profit or margin on the value of its rate base. This percentage of profit or margin (called rate of return) varies, with the higher returns generally allowed for investor-owned utility companies.
Rate case - When a power supplier formally applies to a regulatory agency for an increase in its electric rates.
Rate class - A grouping of consumers of similar usages to which the same rate is applied.
Rate design - The process of determining how the revenue from a rate class is to be recovered through the facilities charge, kWh charge and kW charge.
Rate of return - The percentage of margin an electric supplier is allowed to earn on its rate base through its rates.
Rate schedule - A statement of the financial terms and conditions governing a class or classes of utility services provided to a customer. Approval of the schedule is given by the appropriate ratemaking authority.
REA - Rural Electrification Administration, created when Congress passed the Rural Electrification Act in 1936. The precursor to RUS.
Reactance - Impedance of AC circuit due to capacitance or inductance, expressed in ohms.
REC - Rural electric cooperative. Individual, consumer-owned, non-profit electric cooperatives that provide electric energy and related services to a large section of the county, mostly rural in nature. RECs had their beginnings with passage of the Rural Electrification Act in 1936, which allowed a means for people to join together and borrow money to build their own electrical systems and bring central-station electrical service to their farms and homes.
Receptacle - A contact device installed at the outlet for the connection of an attachment plug. Can be single or multi-outlet.
Receptacle (isolated ground) - These receptacles are generally used for computers, medical, communication, and laboratory type electronic equipment. When this type of equipment is grounded through the conventional building ground, transient signals often cause their circuits to malfunction. The solution is the use of isolated ground receptacles that provide a pure grounding path separate from the conventional grounding circuit within the building. Caution: The grounding terminal must be connected to the system grounding terminal of the service or separately derived system.
Rectifier - A device used to change AC to DC.
Regulator - An automatic device used to maintain current or voltage in a circuit.
Reliability - A measure of a utility's ability to deliver uninterrupted electric service to its customers.
Reliability region - A formal intersystem arrangement entered into for the purpose of enhancing reliability and to allow the combined resources of several electric systems to be applied to an emergency occurring on any one system.
Reload fuel - In a nuclear power plant, approximately one-third of the nuclear core has to be replaced every third year or so. (See Yellowcake)
Remote-control circuit - Any electric circuit that controls any other circuit through a relay or an equivalent device.
Reserves - That power reserve capacity above firm system load, which is required to provide for (a) regulation within the hour to cover minute-to-minute variations in demand; (b) load-forecasting error; (c) loss of equipment; and (d) area protection. It is the reserve capacity capability needed to ensure a specified standard of service.
Resistance - Force that opposes the flow of current through a conductor, measured in Ohms; the reciprocal of conductance.
Resistor - A passive circuit component that exhibits relatively constant resistance to current flow at all frequencies at the same temperature.
Resonance - Peak frequency response characteristic of AC-driven circuit.
RETAILCO - Provides electricity and other value-added services including, but not limited to, purchase of electricity for resale, energy management services, meter reading, billing, etc. Customer retention and growth are key business goals.
Retail competition - Open access to a competitor's distribution system for the purpose of selling power to individual retail customers. Laws are being passed on a state-by-state basis.
Retail wheeling - Competitive access to retail customers which does away with the concept of franchise or service territory. The delivery of electricity to end-users by a third party using the local utility's delivery system.
Revenue requirement - The total amount of money determined to be needed from the sale of electricity. Includes normal operating costs, depreciation expense, taxes, interest on debt and an allowance for margins.
Rheostat - A device that regulates current by means of adjustable resistors.
Right-of-way - (1)The right to pass over property owned by another party. (2)The strip of land over which power lines are built.
Ripple control - A load-management technique that permits the switching on or off, by remote control from a central point, a large number of various appliance and motor loads. Using a utility's network of electric lines as the signal transmission system, an electric impulse is superimposed on the normal supply voltage to trigger whatever switches are attuned to that signal.
Rotor - The part of an electric generator that turns.
RTE (Regional Transmission Entity) - a term referring to any regional entity that might be developed to operate or coordinate the use of transmission in a specified geographical area.
RTG (Regional Transmission Group) - Made up of members who are stakeholders in transmission grid operations in the region, includes marketers, generators, GRIDCOs, and state regulatory commissions. Has governing authority over all GRIDCOs within the RTG, and is subject to FERC jurisdiction.
RTO (Regional Transmission Operator) - An organization defined under FERC Order 2000 that meets certain characteristics and provides certain required services related to the operation of a transmission system within a broad geographic region.
Rulemaking - A formal proceeding by a governmental agency to set broad rules that will apply in many different cases coming before the agency. Affected utilities and the public are given an opportunity to offer comments on each proposed rule prior to its adoption.
RUS - Rural Utilities Service. Federal agency which deals, among others, with electric cooperatives. The successor to the REA.
R-Value - A numeric way of expressing the resistance to the flow of heat through a certain thickness of material. The higher the number, the better the value for use as insulation.
SAFSTOR - Possesion-only license of a non-producing nuclear facilty.
Sag - (1) the difference in elevation of a suspended conductor, usually measured vertically at mid-span from the conductor to what would be a straight line joining its two points of support.
(2) Also known as brownouts, sags are short-term decreases in voltage levels,
SEER -Seasonal Energy Efficiency Ratio.
SCADA - A technological system of supervisory control and data acquisition.
Scrubber - A pollution control device designed to remove solids and other materials, such as sulfur dioxide, from the gases exhausted by smokestacks of fossil-fuel-fired generating plants.
Semiconductor - Any of the class of materials with conductivity that of conductor at high temperatures and nearly absent at low.
SERC - Southeastern Electric Reliability Council, a regional electric reliability council area consisting of part of Virginia, Tennessee, North Carolina, South Carolina, Georgia, Alabama, Florida and part of Mississippi.
Series circuit - An electrical circuit with all parts connected in sequence so that there is only one path for current flow.
SERVCO - A services company.
Service drop - The overhead conductors between the electric supply line and the building or structure being served.
Service factor - The amount of allowable overload indicated by a multiplier which, when applied to a horsepower rating, indicates the permissible loading.
Service point - The point of connection between the facilities of the serving utility and the customer's premises wiring. This is where the metering equipment will be located.
Short circuit - An abnormal condition caused by direction connection between points of low resistance on a circuit. This usually results in circuit bypass or break due to the excessive flow of current. Often, an unintended path of low resistance will allow the current to flow around, rather than through, an intended component or circuit.
Short circuit and ground-fault protection device - A protection device that does not protect against overload.
Short circuit withstand rating - The highest current (at a specified voltage) at the equipment line terminals that the equipment can safely carry until the over-current device opens the circuit.
Short circuit current on the load side of electrical equipment increase to extremely high levels and can do extensive damage to electrical components in a very short period of time. Short circuit current in excess of the equipment rating can damage the equipment because of thermal and magnetic forces. Every electrical component has a maximum short circuit withstand rating that should not be exceeded.
All circuit components that are affected by shorts and grounds must be able to handle the conditions of a fault (heat and magnetic effects from high currents) from the time that the fault occurs, to the time the over-current protection device (fuse or circuit breaker) opens. This current rating is generally marked on the equipment. If not so marked, the equipment is rated for as maximum of 5,000 amperes.
Shunt-trip circuit breaker - A breaker that is capable of being opened through the use of an electromechanical relay, which is controlled through a remote switch. The shunt trip push button is not a disconnect.
Shotgun stick - An 8-foot insulated stick, usually made of fiberglass, which has manually operated mechanisms for gripping and turning. The extension, also known as a hot stick provides the lineman with a means to perform work while remaining a safe working distance from energized power lines.
Sine wave - A waveform that represents periodic oscillations with the same representation as a sine curve.
Single-phase - A single voltage and current in the supply of electricity.
Single pole - Transmission lines are constructed either of aluminum or copper wires. These wires are carried on either steel tower or wood pole structures. One of these wood transmission poles is referred to as a single pole structure.
SMD (Standard Market Design) - A proposal by FERC to standardize markets across the United States in order to ensure non-discriminatory access to transmission.
Splice - The electrical and mechanical connection between two pieces of cable.
Solid-state - A term designating an electronic device that utilizes properties of semiconductor materials, not electron tubes.
Solar photovoltaic system - The total components and subsystems that, in combination, convert solar energy into electrical energy suitable for connection to a utilization load.
SPP - Southwest Power Pool, a regional electric reliability council area consisting of part of Missouri, Kansas, Oklahoma, Arkansas, part of Mississippi, Louisiana, part of New Mexico, and part of Texas.
Span - The horizontal distance between two adjacent power poles or supporting points of a conductor.
Spike - Also referred to as an impulse, a spike is an instantaneous, dramatic increase in voltage.
Spinning reserve - Extra electrical capacity held in reserve by power suppliers in case it is needed. It is connected to the bus and is immediately available for use.
Standby Generator - Standby generators are devices intended to supply on-site generated power to selected loads and may be started either automatically or manually. They are typically used in industrial and commercial buildings, farm and livestock confinement buildings, and in residences. They serve loads such as heating and refrigeration systems, ventilation, data processing and communications systems, and industrial processes that, when stopped during any power outage, could cause discomfort, interruption of processes, damage to perishable products, loss of employee productivity, or the like.
Standby generators must be of the type suitable for the locations in which they are installed and be of adequate capacity and rating for the supply of all equipment intended to be operated at one time. They require the on-site installation and use of special transfer equipment that is designed to prevent the inadvertent interconnection and back-feed of electricity to the utility lines.
Standby generator systems should be tested periodically, and under load, to ensure they are maintained in proper operating condition. It is advised for operators to keep a written record of such tests and maintenance.
Starter - A controller designed to accelerate a motor to normal speed. A starter contains overload protection devices, whereas a lighting contactor does not.
Steady state - A long-term continuous circuit condition.
Step up / Step down - The process in transformers that increases or decreases voltage depending upon the turn ratio.
Stranded costs - Stranded costs are all prudent operations, maintenance, capital, and fuel costs incurred by a regulated utility that (1) cannot be recovered through the traditional rate base procedures and (2) are a direct result of restructuring by the local Public Utilities Commission.
Stranded costs of Generation - Stranded costs of generation are all prudent capital costs associated with generation and contract costs associated with Independent Power Producers incurred by a regulated utility that (1) cannot be recovered through the traditional rate base procedures and (2) are a direct result of restructuring by the FERC.
Substation - An electrical facility containing switches, circuit breakers, buses, and transformers for switching power circuits and transforming power from one voltage to another, or from one system to another.
Superconductivity - The ability of certain metals to conduct current without resistance at very low temperatures.
Surge -A short-term increase in voltage, typically lasting at least 1/120 of a second.
Surge control - A multiple outlet plug that provides transient protection from sudden increases in current in electronic devices.
Switch - A device for making or breaking connections in an electric circuit, thereby permitting or preventing the flow of current. A switch may also be used for changing the connections within a circuit.
Switch, bypass isolation - A manually operated device used in conjunction with a transfer switch to provide a means of directly connecting load conductors to a power source, and of disconnecting the transfer switch.
Switch, general use - A switch intended for use in general distribution and branch circuits. It is rated in amperes, and it is capable of interrupting its rated current at its rated voltage.
Switch, isolating - A switch intended for isolating an electric circuit from the source of power. It has no interrupting rating, and it is intended to be operated only after the circuit has been opened by some other means.
Switch, knife - A switch in which the circuit is closed by a moving blade engaging contact clips.
Switch leg - Slang term to mean the conductor form the load side of the switch to the equipment. The National Electrical Code refers to this as a switch loop.
Switch, motor-circuit - A switch rated in horsepower that is capable of interrupting the maximum operating overload current of a motor of the same horsepower rating as the switch at the rated voltage.
Switch, transfer - An automatic or non-automatic device for transferring one or more load conductor connections from one power source to another.
Switching system - An assemblage of equipment for the sole purpose of tying together two or more electric circuits through switches, selectively arranged to permit a circuit to be disconnected, in case of trouble, or to change the electric connections between the circuits.
System demand - The amount of kilowatts required in any time period to supply firm energy to a utility's consumers, including all contributable losses such as line, wheeling and transformer losses.
System interconnection - A physical connection between two electric systems that permits the transfer of electric energy in either direction.
Take-and-pay - A power sales contract stipulating that payment will be made only for power actually delivered.
Take-or-pay - Under a take-or-pay power sales contract, payment must be made whether or not the power contracted for is received. Such an arrangement is required, for example, in ratchet contracts and for projects that are financed by the issuance of electric revenue bonds (bonds that must be repaid from electric revenues only).
Tariff - A published volume of rate schedules and general terms and conditions under which a product or service will be supplied. (See electric rate schedule).
Terminal - The point of current entry or departure from a circuit; a metal nut on screw or other mechanical device that connects wire to another apparatus.
Therm - A unit of heat equal to 100,000 BTUs.
Thermal plant - A unit that uses heat to generate electricity. "Thermal" is from the Greek word, "therme," which means heat.
Thermocouple - An electric circuit composed of two dissimilar metals joined at different temperatures.
TIER - Times Interest Earned Ratio. Patronage capital and margins, plus interest expense, divided by interest on long-term debt. TIER is used as a measure of a particular electric cooperative's ability to pay back the interest on its loans.
Time-of-day metering - A metering system that measures a customer's power usage at various intervals during each 24-hour period. By this means, a utility can determine which of its customers are using the most power at the time of the system's maximum peak demand and are, thereby, making the heaviest contributions to the system's peak.
Top sheet - The recommendations by the staff of the Federal Energy Regulatory Commission (FERC) concerning a wholesale rate increase application.
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TRANSCO/GRIDCO - constructs and maintains transmission facilities.
Transfer pricing - The price charged by one division of a firm to another division of the same firm.
Transformer - A device that changes electric power from one voltage level to another. Use of transformers allows electricity to be sent and distributed over long distances of conductor to the end-user. Transformers may be used to either increase or decrease the voltage.
Transmission - The means of transporting electric power from one point to another, usually at voltages over 69,000.
Transmission line - High-voltage conductors that carry electric power from generating plants to load centers and substations.
Trended cost - What it would cost today to replace equipment (such as a generating unit) that was built a number of years ago, or to construct such a facility at a certain time in the future, at projected costs compared to today's costs.
Turbine - An engine in which high-pressure steam, water, gas, or air is made to spin a rotating shaft by pushing on angled blades. Turbines are among the most powerful machines. Steam turbines are used to drive generators in electric power stations.
Turbine, combustion - A turbine in which the fuel (fuel oil or gas) is burned within the turbine itself. The expanding gases that result from the burning fuel are forced through the turbine blades. Combustion turbines generally cost less to build, but they have higher fuel costs than steam turbines and are normally used only as peaking plants.
Uniform system of accounts- A standard system of classification for revenues, expenses, assets and liabilities, prescribed by RUS for use by cooperatives.
Universal Access- the requirement to provide electric service to all consumers. The government or competing utilities must see to it that all consumers receive reliable electricity at an affordable price even after deregulation.
UPS - An uniterruptible power supply device, commonly used in conjunction with computers and sensitive electronics to maintain electric power during an outage or to allow enough time for an orderly shut-down on the customer's equipment.
Utility- An organization responsible for the installation, operation, or maintenance of electric supply or communications systems.
Vertically Integrated- A utility that combines the functions of generation, transmission and distribution.
Volt- Electromotive force or electric potential; the "pressure" of electricity. (Symbol V) One volt produces a current of one ampere in a resistance of one ohm.
Voltage- Term commonly used for potential difference.
Voltmeter- An instrument for measuring potential difference (voltage).
Watt- A unit of power. (Symbol W) It represents the rate of expenditure or consumption of energy. It is the power used when one joule of work is done in one second. In electrical terms, the flow of one ampere of current through a conductor whose ends are at a potential difference of one volt uses one watt of power. (watts = volts X amps)
Weatherhead- The fitting at a conduit used to allow conductors entry, but prevent weather entry.
WECA - Wisconsin Electric Cooperative Association, a division of the Wisconsin Federation of Cooperatives, headquartered in Madison, Wisconsin.
WFC - Wisconsin Federation of Cooperatives, headquartered in Madison, WI.
Wheeling- One utility transmitting power over its lines on behalf of a second utility.
Wheeling charge - An amount charged by one electrical system to transmit the energy of, and for, another system or systems.
Wheeling service - The movement of electricity from one system to another over transmission facilities of intervening systems. Wheeling service contracts can be established between two or more systems.
Wholesale sales - Energy supplied to other electric utilities, cooperatives, municipalities, and Federal and State electric agencies for resale to ultimate consumers.
WUMS - Wisconsin Upper Michigan System
Winding - Wire around an armature to act as a coil.
Wire gages - The American Wire Gage (AWG), formerly known as Brown & Sharpe (B&S), is the standard gage for copper, aluminum, and other conductors, excepting only steel conductors, for which the Steel Wire Gage (Stl WG) is used.
WSCC - Western Systems Coordinating Council, a regional electric reliability council consisting of Washngton, Oregon, Idaho, part of Montana, Wyoming, Colorado, Utah, Nevada, California, Arizona, and part of New Mexico.
WWMPG - Western Wisconsin Municipal Power Group. It is the organization formed by the municipal utilities that Dairyland Power Cooperative serves. It was formed to give the municipals bargaining power.
Yellowcake - In a nuclear power plant, this is the portion of the nuclear core has to be replaced every third year or so.
Youth Leadership Congress - A learning experience designed for high school students, coordinated and co-sponsored by the Wisconsin Electric Cooperative Association (a division of Wisconsin Federation of Cooperatives). The event is held annually on the UW-River Falls campus and is cosponsored by the College of Agriculture.