ABB RELION 650 SERIES, Technical Manual

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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 24
1MRK 506 382-UEN A
Glossary
932 Line distance protection REL650 2.2 IEC
Technical manual