NERC Vocabulary & Answer key
A BA whose BA area is interconnected with another BA
Adjacent Balancing area either directly or via a multi-party agreement or
Authority transmission tariff.
The impact of an event that results in frequency-related
instability, unplanned tripping of load or generation, or
uncontrolled separation or cascading outages that affect a
Adverse Reliability Impact widespread area of the interconnection.
A measure of the expected geomagnetic activity based on
A-Index solar observations for Fredericksburg, VA.
Any interpersonal communication that is able to serve as a
substitute for, and does not utilize the same infra-structure
Alternative Interpersonal (medium) as, interpersonal communication used for day-to-
Communication day operations.
The instantaneous difference between a Balancing
Authority's net actual and scheduled interchange, taking
into account the effects of Frequency Bias, correction for
meter error, and Automatic Time Error Correction (ATEC),
if operating in the ATEC mode.
Area Control Error (ACE) ATEC is only applicable to Balancing Authorities in the
Western Interconnection.
The state where a request for interchange (initial or
Arranged Interchange revised) has been submitted for approval.
A BA bringing generation or load into its effective control
Attaining Balancing boundaries through a Dynamic Transfer from the Native
Authority BA.
Equipment that automatically adjusts generation in a BA
area from a central location to maintain the BA's
interchange schedule plus frequency bias. AGC may also
Automatic Generation accommodate automatic inadvertent payback and time
Control (AGC) error correction.
, NERC Vocabulary & Answer key
A measure of the transfer capability remaining in the
physical transmission network for further commercial
activity over and above already committed uses. It is
defined as Total Transfer Capability, less Existing
Transmission Commitments (including retail customer
Available Transfer service), less a Capacity Benefit Margin, less a
Capability (ATC) Transmission Reliability Margin, plus Postbacks, plus
counterflows.
A generating unit(s) and its associated set of equipment
which has the ability to be started with support from the
system or is designed to remain energized without
connection to the remainder of the system, with the ability
to energize a bus, meeting the TO's restoration plan needs
for real and reactive power capability, frequency and
Blackstart Resource voltage control, and that has been included in the TO's
restoration plan.
All transmission elements operated at 100kV or higher and
Real Power and Reactive Power resources connected at
100kV or higher including:
• Transformers with the primary terminal and at least one
secondary terminal operated at 100kV or higher
• Generating resources including the generator terminals
through the high side of the step-up transformers connected
at a voltage of 100kV or above
• Blackstart Resources identified in the TO's restoration
plan, and Static or dynamic devices dedicated to supplying
Bulk Electric System (BES) or absorbing Reactive Power that are connected at 100kV
or higher
Some exclusions apply.
Any abnormal system condition that requires automatic or
immediate manual action to prevent or limit the failure of
transmission facilities or generation supply that could
Bulk Electric System adversely affect the reliability of the BES.
Emergency
, NERC Vocabulary & Answer key
A circuit element that stores energy in the form of an
electrical charge and introduces capacitance into a circuit.
Capacitor The stored energy creates an electric field.
A capacity emergency exists when a BA area's operating
capacity, plus firm purchases from other systems to the
extent available or limited by transfer capability, is
Capacity Emergency inadequate to meet its demand plus its regulating
requirements.
The energy profile (including non-default ramp)
throughout a given time period, based on the aggregate of
Composite Confirmed all Confirmed interchange occurring in that time period.
Interchange
The state where no party has denied and all required parties
have approved the Arranged Interchange.
Confirmed Interchange
The unexpected failure or outage of a system component,
such as a generator, transmission line, circuit breaker,
Contingency switch, or other electrical element.
The provision of capacity deployed by the BA to meet the
Disturbance Control Standard and other NERC and
Contingency Reserves Regional Reliability Organization contingency
requirements.
One or more facilities hosting operating personnel that
monitor and control the BES in real-time to perform the
reliability talks, including their associated data centers, of:
• A Reliability Coordinator,
• A Balancing Authority,
• A Transmission Operator for transmission facilities at two
or more locations, or
Control Center • A Generator Operator for generation facilities at two or
more locations
Control Performance The reliability standard that sets the limits of a BA's ACE
over a specified time period.
Standard (CPS)
A BA whose BA area is interconnected with another BA
Adjacent Balancing area either directly or via a multi-party agreement or
Authority transmission tariff.
The impact of an event that results in frequency-related
instability, unplanned tripping of load or generation, or
uncontrolled separation or cascading outages that affect a
Adverse Reliability Impact widespread area of the interconnection.
A measure of the expected geomagnetic activity based on
A-Index solar observations for Fredericksburg, VA.
Any interpersonal communication that is able to serve as a
substitute for, and does not utilize the same infra-structure
Alternative Interpersonal (medium) as, interpersonal communication used for day-to-
Communication day operations.
The instantaneous difference between a Balancing
Authority's net actual and scheduled interchange, taking
into account the effects of Frequency Bias, correction for
meter error, and Automatic Time Error Correction (ATEC),
if operating in the ATEC mode.
Area Control Error (ACE) ATEC is only applicable to Balancing Authorities in the
Western Interconnection.
The state where a request for interchange (initial or
Arranged Interchange revised) has been submitted for approval.
A BA bringing generation or load into its effective control
Attaining Balancing boundaries through a Dynamic Transfer from the Native
Authority BA.
Equipment that automatically adjusts generation in a BA
area from a central location to maintain the BA's
interchange schedule plus frequency bias. AGC may also
Automatic Generation accommodate automatic inadvertent payback and time
Control (AGC) error correction.
, NERC Vocabulary & Answer key
A measure of the transfer capability remaining in the
physical transmission network for further commercial
activity over and above already committed uses. It is
defined as Total Transfer Capability, less Existing
Transmission Commitments (including retail customer
Available Transfer service), less a Capacity Benefit Margin, less a
Capability (ATC) Transmission Reliability Margin, plus Postbacks, plus
counterflows.
A generating unit(s) and its associated set of equipment
which has the ability to be started with support from the
system or is designed to remain energized without
connection to the remainder of the system, with the ability
to energize a bus, meeting the TO's restoration plan needs
for real and reactive power capability, frequency and
Blackstart Resource voltage control, and that has been included in the TO's
restoration plan.
All transmission elements operated at 100kV or higher and
Real Power and Reactive Power resources connected at
100kV or higher including:
• Transformers with the primary terminal and at least one
secondary terminal operated at 100kV or higher
• Generating resources including the generator terminals
through the high side of the step-up transformers connected
at a voltage of 100kV or above
• Blackstart Resources identified in the TO's restoration
plan, and Static or dynamic devices dedicated to supplying
Bulk Electric System (BES) or absorbing Reactive Power that are connected at 100kV
or higher
Some exclusions apply.
Any abnormal system condition that requires automatic or
immediate manual action to prevent or limit the failure of
transmission facilities or generation supply that could
Bulk Electric System adversely affect the reliability of the BES.
Emergency
, NERC Vocabulary & Answer key
A circuit element that stores energy in the form of an
electrical charge and introduces capacitance into a circuit.
Capacitor The stored energy creates an electric field.
A capacity emergency exists when a BA area's operating
capacity, plus firm purchases from other systems to the
extent available or limited by transfer capability, is
Capacity Emergency inadequate to meet its demand plus its regulating
requirements.
The energy profile (including non-default ramp)
throughout a given time period, based on the aggregate of
Composite Confirmed all Confirmed interchange occurring in that time period.
Interchange
The state where no party has denied and all required parties
have approved the Arranged Interchange.
Confirmed Interchange
The unexpected failure or outage of a system component,
such as a generator, transmission line, circuit breaker,
Contingency switch, or other electrical element.
The provision of capacity deployed by the BA to meet the
Disturbance Control Standard and other NERC and
Contingency Reserves Regional Reliability Organization contingency
requirements.
One or more facilities hosting operating personnel that
monitor and control the BES in real-time to perform the
reliability talks, including their associated data centers, of:
• A Reliability Coordinator,
• A Balancing Authority,
• A Transmission Operator for transmission facilities at two
or more locations, or
Control Center • A Generator Operator for generation facilities at two or
more locations
Control Performance The reliability standard that sets the limits of a BA's ACE
over a specified time period.
Standard (CPS)
