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1MRK 511 391-UUS A
670 series 2.2 ANSI
Communication protocol manual
TNC connector
TP
TPZ, TPY, TPX, TPS Current transformer class according to IEC
TRM
TYP
UMT
Underreach
UTC
UV
WEI
VT
X.21
3I
O
3V
O
Threaded Neill-Concelman, a threaded constant impedance
version of a BNC connector
Trip (recorded fault)
Transformer Module. This module transforms currents and
voltages taken from the process into levels suitable for further
signal processing.
Type identification
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
Three times zero-sequence current.Often referred to as the
residual or the ground-fault current
Three times the zero sequence voltage. Often referred to as
the residual voltage or the neutral point voltage
Section 5
Glossary
59
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