ABB REC650 ANSI, Applications Manual

Page: 367 / 370

TC Trip coil
TCS Trip circuit supervision
TCP Transmission control protocol. The most common transport
layer protocol used on Ethernet and the Internet.
TCP/IP 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.
TEF Time delayed gound-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
1MRK 511 286-UUS A
Section 17
Glossary
361
Application manual