Appendixes Appendix A List of Acronyms and Terms

Acronyms V/m: volts per meter WSCC: Western Systems Coordinating Council AC: alternating current ACE: area control error AGC: automatic generation control Terms ANSI: American National Standards Institute CWIP: Construction Work in Progress Alternating Current (AC): Electric current that reverses DC: direct current direction many times per second (120 times per second DOE: Department of Energy in the United States); almost the entire U.S. power DSG: dispersed source of generation system uses AC except for some long-distance direct current (DC) transmission lines. ECAR: East Central Area Reliability Coordination Agreement Automatic Generation Control (AGC): A system used to control the output of electric generators in a control ECC: energy control center area to balance the supply and demand of power and EHV: extra high voltage execute power transactions with neighboring control ELF: extremely low frequency areas. EMS: energy management system Bulk Power System: Includes generating units, trans- Electric Reliability Council of Texas ERCOT: mission lines, and related equipment. FERC: Federal Energy Regulatory Commission Capacity Margin: The difference between generation FPA: Federal Power Act capacity and peak load expressed as a percentage of HVDC: High voltage direct current capacity. IPP: Independent power producer Circuit: A conductor or system of conductors that forms kV: 1,000 volts (kilovolt) a closed loop through which current flows. kW: 1,000 watts (kilowatt) Cogeneration: Production of both electrical (or me- kWh: kilowatthour chanical) energy and thermal energy from the same LOLP: loss of load probability primary energy source. MAAC: Mid-Atlantic Area Council Conductors: Bundled strands of wire that carry electric MAIN: Mid-American Interconnected Network current. MAPP: Mid-Continent Area Power Pool Control Area: A region with an energy control center MW: 1 million watts (megawatt) responsible for operating the power system within that NARUC: National Association of Regulatory Utility area. Commissioners Coordinating Transactions: Involves the scheduling NEPA: National Environmental Policy Act of 1969 and control of generation to implement power trans- NEPOOL: New England Power Pool fers, as well as monitoring and recording the transac- NERC: North American Electric Reliability Council tions for billing or for other compensation. NOPR: notice of proposed rulemaking Direct Current (DC): Electric current that flows continu- NRC: Nuclear Regulatory Commission ously in one direction. PJM: Pennsylvania/New Jersey/Maryland Intercon- Distribution lines: Power lines delivering electricity to nection customers at relatively low voltages typically between NPCC: Northeast Power Coordinating Council 110 and 69,000 volts. NUG: nonutility generation Economic Dispatch: A system for selecting generating PSD: prevention of significant deterioration units to operate to balance supply and demand at Puc: public utility commission minimum cost. PUHCA: Public Utility Holding Company Act of 1935 Economy Transfers: Power purchased by one system PURPA: Public Utility Regulatory Policies Act of from another because it is less expensive than power 1978 produced by the first system’s own generating facili- QF: qualifying facility ties. SCADA: supervisory control and data acquisition Electric Field: The electric force that a charged object is SERC: Southeastern Electric Reliability Council capable of exerting on other charges in its vicinity. SPP: Southwest Power Pool Hertz (Hz): Frequency measured in cycles per second; VAR: volt-amps-reactive power systems in the United States operate at “60 Hz. –263– 2&? ● Electric Power Wheeling and Dealing: Technological Considerations for Increasing Competition

Load Management: The manipulation of customer Security: The ability of the bulk power system to demand by economic and/or technical means. withstand sudden disturbances, such as the failure of a Loop Flows: Parallel path flows crossing utilities’ generator or transmission line. boundaries along paths not contracted for or sched- Speed Governor: A device on a generating unit which uled. adjusts the unit’s power output to maintain the exact Loss of Load Probability (LOLP): A measure of the frequency. long-term expectation that a utility will be unable to Stability: The ability to maintain synchronous operation meet customer demand. following disturbance. Magnetic Field: The magnetic force that a charged object Substations: A collection of power system equipment, is capable of exerting on other charges in its vicinity. such as voltage transformers, circuit breakers, and Qualifying Facility (QF): Generating unit qualifying for switches. special regulatory treatment under the Public Utility Regulatory Policies Act of 1978. Supervisory Control and Data Acquisition: Telemetry Radial or Feeder lines: Transmission lines connected to and control equipment which monitors voltages and the grid at only one end; the other end is connected power flows and coordinates the transmission line and either to a power plant or distribution system. voltage control equipment. Ramp Rate: The rate at which a generator’s power output Telemetry: Monitoring and communication equipment. can change. Transmission Access: The ability to use a transmission Reactance: A phenomenon of AC power in which the system. voltage and current are out of phase, that is, they do not Transmission System: An interconnected group of peak simultaneously. individual lines, which transport electricity over long Reactive Power: Power which is stored by reactive distances. elements in a power system; called VARs (Volt-Arnps- Volt: A unit of electromotive force or the electrical Reactive). pressure that can push a current through a circuit; can Real Power: The rate at which energy is delivered to a be positive or negative. load to be transformed into heat, light, or physical Voltage: A measure of the difference in volts between any motion. two conductors or between a conductor and the Reliability: The ongoing ability of a power system to ground, which is considered to be zero. avoid outages and continue to supply electricity with the appropriate frequency and voltage to customers. Watt: The unit of measure of electrical power or the rate Reserve Margin: The difference between generating of doing work. capacity and peak load, expressed as a percentage of Wheeling: The use of the transmission facilities of one peak load. system to transmit power produced by other entities. Retail Wheeling: Wheeling for delivery of power to a Wholesale Wheeling: Wheeling for delivery to a utility retail customer. system.