Glossary of Terms
Glossary of Electric Utility Terms 

Advanced Metering Infrastructure (AMI) - Systems that measure, collect, and analyze energy usage, and communicate with metering devices such as electric meters, gas meters, heat meters, and water meters, either on request or on a schedule.  These systems include hardware, software, communications, consumer energy displays and controllers, customer associated systems, Meter Data Management (MDM) software, and supplier business systems.  AMI extends current advanced meter reading (AMR) technology by providing two-way meter communications, allowing commands to be sent toward the home for multiple purposes, including "time-of-use" pricing information, demand-response actions, or remote service disconnects.

Alternating current - Electric current in which the direction of flow is reversed at frequent intervals: usually 100 or 120 times per second (50 or 60 cycles per second or 50//60 Hz).

Ampere (A) or amp - The basic SI unit measuring the quantity of electricity. The unit for the electric current; the flow of electrons. One amp is 1 coulomb passing in one second. One amp is produced by an electric force of 1 volt acting across a resistance of 1 ohm.

Annual Transmission Revenue Requirement (ATRR) - FERC-ordered revenue paid to transmission owners by ratepayers for the recovery of prudently incurred costs of transmission construction and operation plus an allowed rate of return. 

Auction Revenue Right (ARR) - A financial right, awarded during the annual ARR allocation process that entitles the holder to a share of the auction revenues generated in the applicable Transmission Congestion Right (TCR) auction(s) and/or entitles the holder to self-convert the ARR's into TCR's.

Automatic circuit re-closer - A self-controlled device for interrupting and re-closing an alternating current circuit with a predetermined sequence of opening and re-closing followed by resetting, hold-closed, or lockout operation.

Automatic Meter Reading (AMR) - The technology of automatically collecting consumption, diagnostic, and status data from water meter or energy metering devices and transmitting that data to a central database for billing, troubleshooting, and analyzing.

Availability Factor - For a power plant, this is the amount of time that the plant is able to produce electricity over a certain period, divided by the amount of the time in the period.

Baseload Energy - Electric energy supplied by a generating unit that runs more or less constantly to be at its peak efficiency.  Base load generating units are generally expensive to build, but the least costly to operate due to the relatively low cost of fuel they use (nuclear, coal).

Behind the Meter - Commonly refers to the flow of electricity before it hits the meter on the transmission system wires.

Black-Out - Refers to a condition when all electrical power is disrupted to your area.

British Thermal Unit (BTU) - A unit of heat equal to the amount of heat required to raise one pound of water one degree Fahrenheit at one atmosphere pressure; equivalent to 251.997 calories.  MMBTU is a thousand thousand, or one million, BTU's.

Brown-Out - Refers to a condition when the system voltage drops below acceptable levels causing lights to dim and potentially causing other electrical equipment to function improperly or to be damaged.

Capacity - The load for which a generating unit, generating plant or other electrical apparatus is rated by either the user or by the manufacturer.

Capacity Factor - The net capacity factor of a power plant or generating unit is the ratio of its actual output over time, to its potential output if it were possible for it to operate at full nameplate capacity indefinitely.

Circuit - A conductor or system of conductors through which an electric current is intended to flow.

Cogeneration - A process in which an industrial facility uses its waste energy to produce heat or electricity.

Coincident Peak Demand  - The demand of individual customers that coincides (in time) with the peak demand of the whole system.  For KPP, the coincident peak demand is the peak demand of each member utility at the same time interval that KPP's aggregate peak demand is set.

Combined Cycle - A combined cycle is characteristic of a power producing engine or plant that employs more than one thermodynamic cycle.  In a combined cycle power plant (CCPP), or combined cycle gas turbine (CCGT) plant, a gas turbine generator generates electricity and the waste heat is used to make steam to generate additional electricity via a steam turbine; this last step enhances the efficiency of electricity generation.

Combustion Turbine - Combustion turbines are designed to start quickly to meet the demand for electricity during peak operating periods. They are normally run with natural gas as a fuel although diesel fuel can also be used as needed. The turbines operate like a jet engine: they draw in air at the front of the unit, compress it, mix it with fuel, and ignite it. The hot combustion gases then expand through turbine blades connected to a generator to produce electricity.  Most combustion turbines in municipal power plants are internal combustion turbines, in which fuel is burned in a combustion chamber inside the engine.  Some municipal plants have steam turbines, which are external combustion turbines that burn fuel to heat water in external chambers that, in turn, produces steam energy to turn a turbine to generate electricity.

Conductor - A wire or combination of wires not insulated from one another, suitable for carrying electric current.

Congestion - A situation where the desired amount of electricity is unable to flow due to physical limitations (line, bus, storm damages) or regulated limitations, such as contingency reserves.  Congestion impairs the ability to use least-cost electricity to meet demand, and a price difference between source and sink.

Congestion Hedging - A strategy used to reduce the risk of adverse price movements in an asset due to transmission overcrowding.

Connector - A device providing electrical connection/disconnections. It consists of a mating plug and receptacle. Various types of connectors include DIP, card edge, two-piece, hermaphroditic and wire-wrapping configurations. Multiple contact connectors join two or more conductors with others in one mechanical assembly.

Control Area - A geographic area defined by an interconnected transmission grid and power plant system in which the balance between electric energy supply and demand is generally coordinated by the dominant investor-owned utility to maintain system safety and reliability.

Cost-based Rate - A rate or price charged by energy suppliers based on the cost of providing the energy.  See also Market-based Rate

Cost of Service (COS) Study - A rate study that allocates the total cost of providing electric service to groups of similar customers, based on energy usage, peak use timing, character of service, load factor, voltage, type of metering needed, etc.

Customer Information System (CIS) - Software used to support a data base for customer billing information and account activity.

Cyber Security - Protection of digital assets (SCADA, AMI, OMS) across the organization from hacker attacks and meeting external regulations for such protection.

Dashboard - A simple display of information or data for a single purpose, such as the temperature or a calendar.  A utility dashboard may display current system information.

Day-Ahead Market - The financially binding market for energy and operating reserve that is conducted on the day prior to the Operating Day.

Declining Block Rate - A schedule of prices for electricity wherein the first "block" used by a customer is priced at one rate and the next block(s) at successively lower rates.

Demand - In electric systems, the amount of energy necessary to serve the real time energy needs of end users.

Demand Meter - A meter that measures peak demand (in addition to consumption) during a billing period.

Demand Rate - The rate (per month) charged for the maximum amount of electric generating capacity that must be kept available to a customer.

Demand Response - The reduction of electrical consumption at the end-use customer level in response to high wholesale electricity prices, system resource capacity needs, or system reliability events.

Demand Side Management (DSM) - The planning, implementation, and evaluation of utility-sponsored programs to change the timing or reduce the amount of a customer's energy consumption.

Deregulation - The elimination of regulation from a previously regulated industry or sector.

Designated Network Resource (DNR) - A utility energy resource used to meet load or capacity designated to the Southwest Power Pool for transmission reliability requirements.

Distributed Generation - A method of generating electricity from small energy sources very near to the point of consumption, which may be operated independent of the local distribution system or in parallel with it.
Distribution - The process of delivering electric power at lower voltages from central substations to the point of end use.

Distribution Automation - A system consisting of line equipment, communications infrastucture, and information technology that is used to gather intelligence about a distribution system.

Distribution Management System (DMS) - A collection of applications designed to monitor and control the entire distribution network efficiently and reliably.  The DMS acts as a decision support system to assist the control room and field operating personnel with the monitoring and control of the electric distribution system.  Improving the reliability and quality of service in terms of reducing outages, minimizing outage time, maintaining acceptable frequency and voltage levels are the key deliverables of a DMS.

Distribution Transformers - Distribution transformers reduce the voltage of the primary circuit to the voltage required by customers.

Dual Feed - When a customer is served by two electric lines, usually from different substations.

Dynamic Voltage Regulation (DVR)


Economic Dispatch (aka Units Most Likely) - The practice of using electric power generated from the least expensive units first and then going up the list of available generating resources in ascending order of their operating expenses or submitted bids, until sufficient electricity is committed to meet consumer demand.

Energy Imbalance - The difference between actual energy production or usage and scheduled energy production or usage.

Energy Imbalance Service (EIS) - Essentially, an energy market operated by the Regional Transmission Organization, such as the Southwest Power Pool, that provides asset owners the infrastructure necessary to offer their resources into the marketplace for use in providing Energy Imbalance.

Energy Cost Adjustment - A provision in a rate schedule that provides for an adjustment to the cutomer's bill if the cost of energy to the supplier varies from a specified unit cost.

Federal Energy Regulatory Commission (FERC) - An independent regulatory agency that regulates wholesale sales of electricity and interstate transmission of electricity mostly by investor-owned utilities, but also by public power utilities and rural electric cooperatives in some cases, under the Federal Power Act of 1935. 

Flowgate - A transmission facility or transmission element(s) that has been identified as limiting the amount of power that can be reliably transferred over the bulk transmission system.

Generating Capacity - The maximum output, usually quantified in megawatts, that electric generating equipment can supply to electric system load.

Geographic Information System (GIS) - A system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data.

Gigawatt (GW) - One billion watts. One million kilowatts. One thousand megawatts.

Greenfield Status: A term used to describe an end point wherein a parcel of land that had been in industrial use is, in principle, restored to the conditions existing before the construction of the plant.

Heat pump - Like an air conditioner or refrigerator, a heat pump moves heat from one location to another. In the cooling mode, heat pumps reduce indoor temperatures in the summer by transferring heat to the ground. Unlike an air conditioning unit, however, a heat pump's cycle is reversible. In winter, a heat pump can extract heat from the ground and transfer it inside. The energy value of the heat thus moved can be more than three times the cost of the electricity required to perform the transfer process.

Heat Rate - A measure of the number of BTU's of fuel needed to produce one kilowatt of electric energy.  The lower the heat rate, the higher the efficiency of a generating unit.

Impedance - The total opposition that a circuit offers to the flow of alternating current or any other varying current at a particular frequency.

Independent System Operator (ISO) - A regional organization of transmission line owners that operates the regional transmission network independently of the owners, simplifying the regional transmission rate structure and ensuring non-discriminatory access to the regional transmission system by thrid parties.  Any ISO meeting FERC transmission management requirements is also considered a Regional Transmission Organization (RTO) under FERC.  The Southwest Power Pool (SPP) is the Independent System Operator/Regional Transmission Organization for the region that includes parts of Kansas, Nebraska, Oklahoma, Louisiana, Missouri, Mississippi, New Mexico, and Texas. 

Integrated Marketplace

Intelligent Electronic Device (IED) - A term used in the electric power industry to describe microprocessor-based controllers of power system equipment, such as circuit breakers, transformers, and capacitor banks.  An IED receives data from sensors and power equipment, and can issue control commands, such as tripping circuit breakers if they sense voltage, current, or frequency anomalies, or raise/lower voltage levels in order to maintain the desired level.

Interactive Distributed Generation (IDG) - A small, on-site power suipply system used to generate efficient power to a retail customer during high-cost, peak-demand periods and backup protection during power interruptions.

Interactive Voice Response (IVR) - Communication technology that allows a computer to interact with humans through the use of voice.

Interconnection - Generally a reference to the point at which energy enters the distribution system of a utility from the energy source as it leaves a transmission line.  This point is usually in an electric substation where the electric voltage is reduced by a transformer so it may travel through the smaller distributuion lines of the utility.

Intermittent Energy - Electric energy produced from generating units that use renewable sources of fuel, such as wind and water, which are intermittent because the wind does not always blow and water is not always sufficiently replenished by rainfall.

Intermediate Energy - Electric energy produced by generating units that are less expensive to build, but more expensive to operate due to the cost of fuel, usually natural gas.  These units are used when baseload energy is unavailable and before peaking unit energy is needed.  They are also called load following power plants.

Interruptable Power - Power and usually the associated energy made available by one utility to another.  This transaction is subject to curtailment or cessation of delivery by the supplier in accordance with a prior agreement with the other party of under specified conditions.

Inverted Block Rate Design - A rate design for a customer class for which the unit charge for electricity increases as usage increases.

Investor-owned Utility (IOU) - A for-profit company owned by shareholders.  Westar is an example of an investor-owned utility in Kansas.

Joint Action Agency - An umbrella entitiy formed by multiple small public power utilities that have banded together to build or purchase generation and transmission services for their members.  The Kansas Power Pool is an example of a joint action agency in Kansas.

Kansas Corporation Commission (KCC) - The public utilities commission of the state of Kansas run by three Commissioners appointed by the Governor with the approval of the Senate. The Commission has the responsibility of ensuring that natural gas, electricity, telephone and transportation vendors provide safe, adequate and reliable services at reasonable rates.

Kilowatt (kW) - Equal to one thousand watts, this unit is typically used to express the output power of engines or the consumption of electic energy.

Kilowatt-Hour (kWh) - The total number of kilowatts used in one hour.  It is the unit of measure most commonly used to show the energy consumption of an electric retail customer for billing purposes.

Lightning Arresters - Lightning arresters are devices for protecting many different pieces of equipment such as, power poles and towers, power transformers, circuit breakers, bus structures, and steel superstructures, from damage from lightning strikes.

Load - The amount of electric power delivered or required at any specific point or points on a system.  The requirement originates at the consumers' energy-consuming equipment.

Load Factor - The actual load that occurred over a period of time divided by the maximum load that could have occurred over the same period, expressed as a percentage.

Load Forecast - Data used to determine obligation calculations and accessed through the Marketplace Portal.  Load forecasts include weather data and hourly load data.

Load Profile - A graph of the variation in an electrical load versus time.  A load profile will vary according to customer type, temperature, and holiday seasons.

Looped Line - An electric line that is connected at both ends to separate sources, usually two different substations.

Meter Data Management (MDM) - Meter Data Management (MDM) has been traditionally defined as a repository for meter data collected from diverse meter collection systems as well as providing Validation, Estimation and Editing functions, and providing integration with Customer Information Systems (CIS). It is the primary source for meter analysis and load profiling. However, leading MDM system providers now broaden the definition to be a data repository for Operation data which surpasses early generation MDMs by integrating all collection endpoint data such as SCADA, Outage Management System Data, and GIS Mapping Data.

Market-based Rate - A rate or price charged by energy suppliers based on prevailing conditions in a competitive marketplace, usually the energy spot market.  See also Cost-based Rate


Megawatt (MW) - Equal to one thousand kilowatts or one million watts.

Municipal Energy Agency - See Joint Action Agency.

Native Load - The cumulative load (power requirement) of a utility's retail customer base.

Net Metering - An electricity policy which allows utility customers to offset some or all of their energy use with self-produced renewable energy. Net metering works by utilizing a meter that is able to spin and record energy flow in both directions. The meter spins forward when a customer is drawing power from the utility grid (i.e., using more energy than they are producing) and spins backward when energy is being sent back to the grid. At the end of a given month, the customer is billed only for the net energy used.

Network Integration Transmission Service (NITS) - An open access transmission tariff service designed to allow customers to deliver energy from multiple sources to their load under one transmission contract.  The customer pays for use of the transmission system based on its network load at the transmission system's monthly peak.

Non-coincident Peak Demand - For KPP, the peak demand set by each member utility regardless of the KPP aggregate peak demand.

Ohm - The basic SI unit measuring the quantity of electricity. The unit for the electric current; the flow of electrons. One amp is 1 coulomb passing in one second. One amp is produced by an electric force of 1 volt acting across a resistance of 1 ohm.

Oil Circuit Breakers - Oil circuit breakers are used to switch circuits and equipment in and out of a system in a substation. They are oil filled to provide cooling and to prevent arcing when the switch is activated.

Outage Management System (OMS) - A computer system used by operators of electric distribution systems to assist in restoration of power.  Major functions of an OMS include:
  • Prediction of location of use or breaker that opened upon failure;
  • Prioritizing restoration efforts and managing resources based upon criteria such as locations of emergency facilities, size of outages, and duration of outages;
  • Providing information on the extent of outages and number of customers impacted to management, media, and regulators;
  • Calculation of estimation of restoration times;
  • Management of crews assisting in restoration;
  • Calculation of crews required for restoration.

Peak Demand - Peak demand, peak load or on-peak are terms used in energy demand management describing a period in which electrical power is expected to be provided for a sustained period at a significantly higher than average supply level. Peak demand fluctuations may occur on daily, monthly, seasonal and yearly cycles. For an electric utility, the actual point of peak demand is a single half hour or hourly period which represents the highest point of customer consumption of electricity.

Peaking Unit - Generating equipment that is normally operated only during times of high energy demand. 

Peak Shaving - The use of peaking units to minimize the cost associated with high energy demand from external energy sources.

Power Factor - The ratio of the real power flowing to the load to the apparent power in the circuit, and is a dimensionless number between 0 and 1 (frequently expressed as a percentage, e.g. 0.5 pf = 50% pf). Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power will be greater than the real power. In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.

Power Marketing Administration (PMA) - A federal government entity that sells electricity generated at federal sites (mostly hydro power from federal dams) under rates reflecting only the cost of producing the power to other utilities, with preference given to public power and cooperative utilities.  The Western Area Power Administration (WAPA) and the Southwest Power Administration (SPA) are examples of Power Marketing Administrations.

Primary Circuits - These are the distribution circuits that carry power from substations to local load areas. They are also called express feeders or distribution main feeders. The distribution feeder bay routes power from the substation to the distribution primary feeder circuits.

Price Signal - Information relayed, to producers and consumers, via the price charged for a product or service, thus providing a signal to increase supply and/or to decrease demand for the priced item.  Price signals for electricty are frequently made through the design of electric rate structures.

Public Power Utility - A not-for-profit electric utility that is owned and operated by a state or by a political subdivision of a state, such as a municipality or public utility commission.  All KPP members are public power utilities. 

Quick-Start Resource - A resource that can be started, synchronized, and inject energy within 10 minutes of SPP notification.

Radial Line - An electric line that is only connected at one end, usually at a substation.

Reciprocating Internal Combustion Engine (RICE) -

Regional Transmission Organization (RTO) - See Independent System Operator(ISO).                                                                                                                                                                                                                                                                        

Relays - A relay is a low-powered device used to activate a high-powered device. Relays are used to trigger circuit breakers and other switches in substations and transmission and distribution systems.

RP3 (Reliable Public Power Provider) - An APPA electric utility performance program designed to promote excellence in utility operations and customer service.

Renewable Energy -  Energy that comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished).

Residual Load - The sum of hourly metered interchange in a settlement area, plus the sum of all resource meter data submittal locations less all other load meter data submittal location for that settlement area.

Retail Energy - Electric energy sold to end users (retail customers).

Retail Wheeling - The ability of a retail customer to purchase commodity electricity directly from the wholesale market rather than through a local distribution utility.

Revenue Bonds - A municipal debt on which the payment of interest and principal depends on revenues from the particular asset that the bond issue is used to finance. 

Revenue Decoupling - Eliminating the disincentive to actively reduce consumption.

Rural Electric Cooperative (Co-op) - A private, not-for-profit electric utility owned by the customers it serves.


Service Drop - Run of cables from the power company's aerial power lines to the point of connection to a customer's premises.

Settlement Area - A geographic area within the SPP BA area for which transmission interval metering can account for the geographic area's net area load.

Smart Grid - A modernized power grid that uses information and communications technology to gather and act on information, such as information about the behaviors of suppliers and consumers, in an automated fashion to improve the efficiency, reliability, economics, and sustainabilityof the production and distribution of electricity.

Smart Meter - An electric meter that records consumption of electric energy in intervals of an hour or less and communicates that information via remote reporting at least daily back to the utility for monotoring and billing purposes.  Smart meters enable two-way communication between the meter and the central system.

Southwest Power Pool (SPP) - See Independent System Operator (ISO)

Spinning Reserves - The difference between the capability and actual output of generating units which are operating and connected to the electrical network.  Also may refer to the amount of unloaded generating capability, on units that are in the generating mode and connected to the interconnected system, which can be fully applied in 10 minutes.

Substations - A high-voltage electric system facility. It is used to switch generators, equipment, and circuits or lines in and out of a system. It also is used to change AC voltages from one level to another, and/or change alternating current to direct current or direct current to alternating current.

  • Distribution Substation - These are located near to the end-users. Distribution substation transformers change the subtransmission voltage to lower levels for use by end-users.

Substation Automation (SA) - Using data from Intelligent Electronic Devices (IED's), control and automation capabilities within a substation, and control commands from remote users to control power system devices.

Supervisory Control and Data Acquisition (SCADA) - As used in power plants, SCADA is a software application program for process control; the gathering of data in real time from remote locations in order to control equipment and conditions.

Supply Side Management (SSM) - An effort to change the demand for electricity from the supplier's side of the meter.

Switches - Distribution systems have switches installed at strategic locations to redirect power flows for load balancing or sectionalizing.

System Reliability - Refers to the ability of a transmission system to dependably balance electric energy from a generation source with load requirements by a distribution system, precluding system blackouts. 

Tariff - A document, approved by the responsible regulatory agency, including a schedule of prices, under which utility services will be provided.

Time of Use (TOU) Rates - Prices for electricity that vary depending on what time of day or night a customer uses it.  These rates are designed to reflect the different costs an electric utility incurs in providing electricity during peak periods when electricity demand is high and off-peak periods when electricity demand is low.

Transformer - A devise that is used to reduce ("step down") voltage on electric lines (i.e. from primary to secondary voltage).

Transmission - A term used by most utilities that refers to very high voltage electric lines that are designed to transmit electricity over long distances.

Transmission Bus - Transmission buses are steel structure arrays of switches used to route power in a substation.

Transmission Congestion Right (TCR) - A financial right entitling the holder to a share of the congestion revenue collected in the Day-Ahead Market.

Unbundling - The separating of the total process of electric power service from generation to metering into its component parts for the purpose of separate pricing or service offerings.

Visual Utility (VU)

Volt (V) - A unit of measure of the force, or 'push,' given the electrons in an electric circuit. One volt produces one ampere of current when acting on a resistance of one ohm.

Voltage - The effective (rms) potential difference between any two conductors or between a conductor and ground. Voltages are expressed in nominal values unless otherwise indicated. The nominal voltage of a system or circuit is the value assigned to a system or circuit of a given voltage class for the purpose of convenient designation. The operating voltage of the system may vary above or below this value.

Voltage Drop - The loss of voltage between the input to a device and the output from a device due to the internal impedance or resistance of the device. In all electrical systems, the conductors should be sized so that the voltage drop never exceeds 3% for power, heating, and lighting loads or combinations of these. Furthermore, the maximum total voltage drop for conductors for feeders and branch circuits combined should never exceed 5%.

Watt (W) -The unit of electric power, or amount of work (J), done in a unit of time. One ampere of current flowing at a potential of one volt produces one watt of power.

Wholesale Energy - Energy acquired for sale to retail electric customers.  KPP acquires wholesale energy on behalf of its member cities who then resell the energy at retail to end users.