4.2BSD Unix. TCP/IP was developed by DARPA for
Internet working and encompasses both network layer and
transport layer protocols. While TCP and IP specify two
protocols at specific protocol layers, TCP/IP is often used to
refer to the entire US Department of Defense protocol suite
based upon these, including Telnet, FTP, UDP and RDP.
TEF
Time delayed earth-fault protection function
TLS Transport Layer Security
TM Transmit (disturbance data)
TNC connector Threaded Neill-Concelman, a threaded constant impedance
version of a BNC connector
TP Trip (recorded fault)
TPZ, TPY, TPX, TPS Current transformer class according to IEC
TRM Transformer Module. This module transforms currents and
voltages taken from the process into levels suitable for
further signal processing.
TYP Type identification
UMT User management tool
Underreach A term used to describe how the relay behaves during a fault
condition. For example, a distance relay is underreaching
when the impedance presented to it is greater than the
apparent impedance to the fault applied to the balance point,
that is, the set reach. The relay does not “see” the fault but
perhaps it should have seen it. See also Overreach.
UTC
Coordinated Universal Time. A coordinated time scale,
maintained by the Bureau International des Poids et
Mesures (BIPM), which forms the basis of a coordinated
dissemination of standard frequencies and time signals.
UTC is derived from International Atomic Time (TAI) by
the addition of a whole number of "leap seconds" to
synchronize it with Universal Time 1 (UT1), thus allowing
for the eccentricity of the Earth's orbit, the rotational axis tilt
(23.5 degrees), but still showing the Earth's irregular
rotation, on which UT1 is based. The Coordinated
Universal Time is expressed using a 24-hour clock, and uses
the Gregorian calendar. It is used for aeroplane and ship
navigation, where it is also sometimes known by the
military name, "Zulu time." "Zulu" in the phonetic alphabet
stands for "Z", which stands for longitude zero.
UV Undervoltage
WEI Weak end infeed logic
VT Voltage transformer
Section 25 1MRK 502 071-UEN -
Glossary
770 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
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