ABB Relion 650 Series Technical Manual page 751

1MRK 511 424-UEN B
Bay control REC650 2.2 IEC
Technical manual
UV
WEI
VT
3I
O
3U
O
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
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 20
Glossary
745