ABB RET670 Applications Manual page 884

Section 7
Glossary
878
TCP/IP
TEF
TNC connector
TPZ, TPY, TPX, TPS Current transformer class according to IEC
UMT
Underreach
UTC
UV
WEI
VT
X.21
Transmission control protocol over Internet Protocol. The de
facto standard Ethernet protocols incorporated into 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.
Time delayed gound-fault protection function
Threaded Neill-Concelman, a threaded constant impedance
version of a BNC connector
User management tool
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.
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.
Undervoltage
Weak end infeed logic
Voltage transformer
A digital signalling interface primarily used for telecom
equipment
1MRK504116-UUS C
Application manual