ABB RELION 670 Series Installation Manual page 109

1MRK 514 026-UEN B
670 series 2.2 IEC
Installation manual
UV
WEI
VT
X.21
3I
O
3U
O
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 earth-fault current
Three times the zero sequence voltage. Often referred to
as the residual voltage or the neutral point voltage
Section 10
Glossary
103