Schweitzer Engineering Laboratories SEL-421-4 - Page 1497

GL.5
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Glossary
Bus Coupler (see also Tie Breaker)—Circuit Breaker Report
Bus Coupler
(see also Tie Breaker)
Equipment with at least a CT and circuit breaker, connecting two busbars when
the circuit breaker is closed. Disconnects of other terminals at the station
(feeders, lines, etc.) are normally arranged in parallel with the bus coupler.
Closing two or more disconnects of the other terminals bypasses the bus coupler,
forming a connection without a circuit breaker between two or more busbars.
Busbar
Protection Element
Each busbar protection elements comprise a differential element, a directional
element, and a fault detection logic.
Bus Sectionalizer
(see also Buscoupler)
Equipment with at least a CT and circuit breaker, connecting two busbars when
the circuit breaker is closed.
Bus-Zone-to-Bus-Zone
Connection Variable
SELOGIC variable stating the conditions when the relay merges two zones to
form a single protection zone.
Bus-Zone
(see also Protection Zone)
Area of protection formed by a minimum of two terminals.
C37.118
IEEE C37.118, Standard for Synchrophasor Measurements for Power Systems.
C37.238
IEEE C37.238, Standard Profile for Use of IEEE 1588 Precision Time Protocol
in Power System Applications.
Capacitor Bank
Assembly of a number of capacitor units.
Capacitor Element
Device consisting of two electrodes separated by a dielectric.
Capacitor Unit
Assembly of a number of capacitor elements.
Category
A collection of similar relay settings.
CCVT
Coupling-capacitor voltage transformer that uses a capacitive voltage divider to
reduce transmission voltage to a level safe for metering and relaying devices. See
CVT.
Checksum
A method for checking the accuracy of data transmission involving summation of
a group of digits and comparison of this sum to a previously calculated value.
Check Zone
Protection zone formed by two or more terminals where the differential
calculation is independent of the status of the disconnect auxiliary contacts.
CID
Checksum identification of the firmware.
CID File
IEC 61850 Configured IED Description file. XML file that contains the
configuration for a specific IED.
Circuit Breaker
Failure Logic
This logic within the relay detects and warns of failure or incomplete operation of
a circuit breaker in clearing a fault or in performing a trip or close sequence.
Circuit Breaker
History Report
A concise circuit breaker event history that contains as many as 128 events. This
breaker history report includes circuit breaker mechanical operation times,
electrical operation times, interrupted currents, and dc battery monitor voltages.
Circuit Breaker Report
A full report of breaker parameters for the most recent operation. These
parameters include interrupted currents, number of operations, and mechanical
and electrical operating times among many parameters.