GL.6
SEL-587Z Relay
Date Code 20020903
Glossary
HMI
—
MOV
HMI
Human machine interface.
HV
High voltage. System voltage greater than or equal to 100 kV and less than
230 kV.
IA, IB, IC
Measured A-phase, B-phase, and C-phase currents.
IED
Intelligent electronic device.
IG
Residual current, calculated from the sum of the phase currents. In normal,
balanced operation, this current is very small or zero.
Infinite Bus
A constant-voltage bus.
Input Conditioning
The establishment of debounce time and assertion level.
Instantaneous Meter
Type of meter data presented by the SEL-587Z Relay that includes the present
values measured at the relay ac inputs. The word “Instantaneous” is used to
differentiate these values from the measurements presented by the demand
and other meter types.
IRIG-B
A time code input that the relay can use to set the internal relay clock.
Jitter
Time, amplitude, frequency, or phase-related abrupt, spurious variations in
duration, magnitude, or frequency.
L/R
Circuit inductive/resistive ratio.
LED
Light-emitting diode. Used as indicators on the relay front panel.
LMD
SEL distributed port switch protocol.
Local Bits
The Relay Word bit outputs of local control switches that you access through
the SEL-587Z Relay front panel. Local control switches replace traditional
panel-mounted control switches.
Lockout Relay
An auxiliary relay that prevents operation of associated devices until reset
either electrically or by hand.
Logical 0
A “false” logic condition, dropped out element, or deasserted control input or
control output.
Logical 1
A “true” logic condition, picked up element, or asserted control input or
control output.
Low-Level Test Interface
An interface that provides a means for interrupting the connection between the
relay input transformers and the input processing module and allows inserting
reduced-scale test quantities for relay testing.
Maintenance Testing
Testing that confirms that the relay is measuring ac quantities accurately and
verifies correct functioning of auxiliary equipment, scheme logic, and
protection elements.
Maximum Dropout Time
The maximum time interval following a change of input conditions between
the deassertion of the input and the deassertion of the output.
MOD
Motor-operated disconnect.
MOV
Metal-oxide varistor.
Содержание SEL-587Z
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