GL.12
SEL-400 Series Relays Instruction Manual Date Code 20171006
Glossary
Fundamental Power—GUI
Fundamental Power
Power calculated with components of the measured electrical signal with a
frequency equal to the normal electrical system frequency, usually 50 Hz or
60 Hz.
Fuse
Device that opens the circuit in which it is connected to provide overcurrent
protection.
Fuseless Capacitor Bank
A capacitor bank without internal or external fuses.
Global Settings
General settings including those for relay and station identifiers, number of
breakers, date format, phase rotation, nominal system frequency, enables, station
dc monitoring, control inputs, settings group selection, data reset controls,
frequency tracking, time and date management, and current and voltage source
selection.
GOMSFE
Generic Object Model for Substation and Feeder Equipment; a system for
presenting and exchanging IED data.
GOOSE
IEC 61850 Generic Object Oriented Substation Event. GOOSE objects can
quickly and conveniently transfer status, controls, and measured values among
peers on an IEC 61850 network.
GPS
Global Positioning System. Source of position and high-accuracy time
information.
Ground Directional
Element Priority
The order the relay uses to select directional elements to provide ground
directional decisions (relay setting ORDER).
Ground-Distance Element
A mho or quadrilateral distance element the relay uses to detect faults involving
ground along a transmission line.
Ground Fault
Loop Impedance
The impedance in a fault-caused electric circuit connecting two or more points
through ground conduction paths.
Ground
Overcurrent Elements
Elements that operate by comparing a residual ground calculation of the three-
phase inputs with the residual overcurrent threshold setting. The relay asserts
ground overcurrent elements when a relay residual current calculation exceeds
ground current setting thresholds.
Ground Quadrilateral
Distance Protection
Ground-distance protection consisting of a four-sided characteristic on an R-X
diagram.
Ground Return Resistance
Fault resistance that can consist of ground path resistance typically in tower
footing resistance and tree resistance.
Grounded Capacitor Bank
Capacitor bank with a solid connection to ground.
Guard-Present Delay
A timer that determines the minimum time before the relay reinstates permissive
tripping following a loss-of-channel condition in the DCUB communications-
assisted tripping scheme (relay setting GARD1D).
GUI
Graphical user interface.
Harmonics
Frequencies that are multiples of the frequency of the power system; 100 Hz is
the second harmonic of a 50 Hz power system.
Harmonic Restraint
Method by which harmonics are used to desensitize differential elements, thereby
avoiding misoperations during inrush conditions.
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