GL.10
SEL-421/SEL-421-1 Relay
Date Code 20020501
Glossary
GOMSFE
—
IA, IB, IC
GOMSFE
Generic Object Model for Substation and Feeder Equipment; a system for
presenting and exchanging IED data.
GOOSE
Generic Object Oriented Substation Event; a GOMSFE object for control
messaging.
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.
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.
Hexadecimal Address
A register address consisting of a numeral with an “h” suffix or a “0x” prefix.
High-Resolution
Data Capture
Reporting of 3 kHz low-pass analog filtered data from the power system at
each event trigger or trip at high sample rates of 8000 samples/second, 4000
samples/second, 2000 samples/second, and 1000 samples/second.
HMI
Human machine interface.
Homogeneous System
A power system with nearly the same angle (<5 ° difference) for the
impedance angles of the local source, the protected line, and the remote
source.
HV
High voltage. System voltage greater than or equal to 100 kV and less than
230 kV.
Hybrid Control Output
Contacts that use an insulated gate bipolar junction transistor (IGBT) in
parallel with a mechanical contact to interrupt (break) high inductive dc
currents. The contacts can carry continuous current, while eliminating the
need for heat sinking and providing security against voltage transients. These
contacts are polarity dependent and cannot be used to switch ac control
signals.
IA, IB, IC
Measured A-phase, B-phase, and C-phase currents.
Summary of Contents for SEL-421
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