ABB REL670 Installation And Commissioning Manual page 197

Glossary
TCP/IP
TEF
TNC connector
TPZ, TPY, TPX, TPS
Underreach
U/I-PISA
UTC
UV
V.36
WEI
VT
X.21
3IO
3UO
Transmission Control Protocol over Internet Protocol. The de facto stan-
dard Ethernet protocols incorporated into 4.2BSD Unix. TCP/IP was
developed by DARPA for internet working and encompasses both net-
work 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 earth-fault protection function
Threaded Neill Concelman, A threaded constant impedance version of a
BNC connector
Current transformer class according to IEC
A term used to describe how the relay behaves during a fault condition.
For example a distance relay is under-reaching when the impedance
presented to it is greater than the apparent impedance to the fault
applied to the balance point, i.e. the set reach. The relay does not "see"
the fault but perhaps it should have seen it. See also Overreach.
Process interface components that deliver measured voltage and cur-
rent values
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 addi-
tion 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 also sometimes known
by the military name, "Zulu time". "Zulu" in the phonetic alphabet stands
for "Z" which stands for longitude zero.
Under-voltage
CCITT interface for 4 wire data communication with a speed exceeding
48Kkbps.
Weak End Infeed logic
Voltage transformer
A digital signalling interface primarily used for telecom equipment
Three times zero-sequence current. Often referred to as the residual or
the earth-fault current
Three times the zero sequence voltage. Often referred to as the residual
voltage or the neutral point voltage
Chapter 14
Glossary
189