Glossary by "F"

  • 276

    Facility rating

    The maximum or minimum voltage, current, frequency, or real or reactive power flow through a facility that does not violate the applicable equipment rating of any equipment comprising the facility.

  • 277

    Fast area regulation

    See: Fast frequency regulation
    Source: ESA Technical Working Group
  • 278

    Fast frequency regulation

    A fast version of area regulation. Ideally fast frequency response resources can respond robustly to the ACE signal, thus output changes every few seconds.

    Source: ESA Technical Working Group
  • 279


    An event or condition occurring on an electric system such as a short circuit, a broken wire, or an intermittent connection.

  • 280

    Fault current

    When an excessive amount of current flows in an uncontrolled manner through the electrical system.  

  • 281

    Federal Energy Management Program

    Acronym(s): FEMP

    U.S. Department of Energy - Office of Energy Efficiency and Renewable Energy - Federal Energy Management Program (U.S. DOE-FEMP) The program assists federal government agencies to reduce energy use and cost, increase energy efficiency, use renewable energy, and conserve water. FEMP’s three primary areas of concentration are project financing, technical assistance, and planning, reporting, and evaluation.

    Source: ESA Technical Working Group
  • 282

    Federal Energy Regulatory Commission

    Acronym(s): FERC

    FERC is an independent agency regulating the interstate transmission of electricity, natural gas and oil, and responsible for maintaining system reliability, ensuring electricity is transmitted in an unbiased manner, and establishing the price of ancillary services necessary for reliable system operation.

  • 283


    An electrical wire/circuit which “feeds” energy to the next lower level of distribution. A feeder may be an underground or an overhead wire.

    Source: ESA Technical Working Group
  • 284

    Firm demand

    That portion of the Demand that a power supplier is obligated to provide except when system reliability is threatened or during emergency conditions.

  • 285

    Firm transmission service

    The highest quality (priority) service offered to customers under a filed rate schedule that anticipates no planned interruption.

  • 286

    Fixed cost

    A cost or expense incurred without regard to whether or how much a respective service, facility or equipment is used (i.e., unlike variable costs; fixed costs are incurred irrespective of how much the service, facility or equipment is used).  

    Source: ESA Technical Working Group
  • 287


    An electrical discharge through air around or over the surface of insulation, between objects of different potential, caused by placing a voltage across the air space that results in the ionization of the air space.

  • 288


    Robust responses to changing needs and opportunities that are enabled by use of a device or technique that is adaptable, versatile and, in some cases, transportable.

    Source: ESA Technical Working Group
  • 289

    Flexible alternating current (ac) transmission system

    Acronym(s): FACTS

    FACTS enables control of power flow on ac transmission lines and to optimize utilization of existing transmission facilities by allowing operation at or near equipment’s thermal operating limits without sacrificing reliability. Core FACTS technologies are thyristors though FACTS also incorporates sophisticated controls, communication and monitoring devices and computer algorithms.

    Source: ESA Technical Working Group
  • 290

    Flexible generation

    Generating capacity whose output can be varied as needed. Flexible generation is said to be dispatchable.

    Source: ESA Technical Working Group
  • 291

    Float charging

    For electrochemical batteries; recharging during which batteries are connected to a constant-voltage supply that maintains the cell in fully charged condition.

    Source: ESA Technical Working Group
  • 292

    Florida Reliability Coordinating Council

    Acronym(s): FRCC

    A not-for-profit corporation in the state of Florida whose mission is to ensure that the bulk power system in Peninsular Florida is reliable, adequate and secure. The FRCC serves as a regional entities with delegated authority from the North American Electric Reliability Corporation (NERC) for the purpose of proposing and enforcing reliability standards within the FRCC Region. See also regional entities.  

  • 293


    The amount of area required for the storage system.

    Source: ESA Technical Working Group
  • 294

    Forced outage

    1.  The removal from service availability of a generating unit, transmission line, or other facility for emergency reasons. 2.  The condition in which the equipment is unavailable due to unanticipated failure.

  • 295

    Frequency bias

    A value, usually expressed in megawatts per 0.1 Hertz (MW/0.1 Hz), associated with a balancing authority area (BAA) that approximates the BAA

  • 296

    Frequency deviation

    A change in Interconnection frequency.

  • 297

    Frequency error

    The difference between the actual and scheduled frequency. 

  • 298

    Frequency response

    (Equipment) The ability of a system or elements of the system to react or respond to a change in system frequency. (System) The sum of the change in demand, plus the change in generation, divided by the change in frequency, expressed in megawatts per 0.1 Hertz (MW/0.1 Hz).