Sel SEL-421 - OOS Logic Relay Word Bits

R.1.46
SEL-421 Relay Reference Manual Date Code 20111215
Protection Functions
Out-of-Step Logic
Tabl e 1 . 41 OOS Lo g ic Rel ay Wor d Bi t s
Name Description
50ABC Positive-sequence current level detector
X6ABC Zone 6
X7ABC Zone 7
UBOSB Unblock out-of-step blocking
OSB Out-of-step blocking
OSTI Incoming out-of-step tripping
OSTO Outgoing out-of-step tripping
OST Out-of-step tripping
67QUBF Negative-sequence forward directional element
67QUBR Negative-sequence reverse directional element
OOSDET OOS condition detected
OSB1 Block Zone 1 during out-of-step condition
OSB2 Block Zone 2 during out-of-step condition
OSB3 Block Zone 3 during out-of-step condition
OSB4 Block Zone 4 during out-of-step condition
OSB5 Block Zone 5 during out-of-step condition
OSBA A-Phase out-of-step blocking
OSBB B-Phase out-of-step blocking
OSBC C-Phase out-of-step blocking