Sel SEL-421 - Directionality; P, Phase Directional Element Logic Diagram; Q, Negative-Sequence Directional Element Logic Diagram

R.1.39
Date Code 20111215 Reference Manual SEL-421 Relay
Protection Functions
Directionality
Figure 1.25 32P, Phase Directional Element Logic Diagram
Figure 1.26 32Q, Negative-Sequence Directional Element Logic Diagram
Directionality
Zone 1 and Zone 2 distance element directions are fixed in the forward
direction. You can select the other distance protection zones (Zone 3, Zone 4,
and Zone 5) independently as forward-looking (F), or reverse-looking (R)
with settings DIR3, DIR4, and DIR5.
Level 1 and Level 2 directional overcurrent element directions are fixed in the
forward direction for residual ground and negative-sequence directional
overcurrent elements. Level 3 and Level 4 residual and negative-sequence
directional overcurrent elements (67Q3, 67Q4, 67G3, and 67G4) share the
same direction as the corresponding zones of distance protection, also using
settings DIR3 and DIR4.
This directional control option is performed in addition to the regular torque
control settings for each element (the torque control setting acts as a
supervisory input).
The phase directional overcurrent elements (67P1–67P4) and the selectable
operating quantity time-overcurrent elements (51S1–51S3) do not have any
built-in directional control. The torque control settings (67P1TC, 67P2TC,
All Phase-to-Phase
Distance Elements Forward
All Phase-to-Phase
Distance Elements Reverse
ZLOAD
VPOLV
ILOP
F32Q
F32P
(Forward)
R32P
(Reverse)
R32Q
Relay
Word
Bit
Relay
Word
Bit
Relay
Word
Bits
Relay
Word
Bit
Relay
Word
Bit
Setting
—
+
—
+
50QF
z2
50QR
32QF
32QR
Relay
Word
Bit
Relay
Word
Bit
Relay
Word
Bit
F32Q
R32Q
Relay
Word
Bit
LOP
Z2FTH
Z2RTH
Enable
Relay
Word
Bit
32QE
SPO
ILOP
Relay
Word
Bits
ELOP := Y
Setting
Calculation
Calculation