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 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
Section 9
1MRK 500 128-UEN B
Glossary
92
650 series 2.2 IEC
Operation manual
