Sel SEL-421 - Negative-Sequence Voltage-Polarized Directional Element Logic; Zero-Sequence Voltage-Polarized Directional Element Logic

R.1.34
SEL-421 Relay Reference Manual Date Code 20111215
Protection Functions
Ground Directional Element
Figure 1.21 Negative-Sequence Voltage-Polarized Directional Element Logic
q From Figure 1.18; w From Figure 1.20
Figure 1.22 Zero-Sequence Voltage-Polarized Directional Element Logic
q From Figure 1.18; w From Figure 1.20
—
+
SPO
F32QG
(Forward)
R32QG
(Reverse)
Relay
Word
Bit
32QGE
Relay
Word
Bit
Relay
Word
Bit
Relay
Word
Bits
50QR
Best Choice
Ground
Directional
Logic
enable output
ILOP
Enable
50QF
V2
I2L
Z2FTH
(Calculation)
—
+
Z2RTH
(Calculation)
z2 Calculation
Relay
Word
Bit
1
2
SPO
Relay
Word
Bits
F32V
(Forward)
R32V
(Reverse)
Relay
Word
Bit
Relay
Word
Bit
32VE
Relay
Word
Bit
50GR
Relay
Word
Bit
ILOP
50GF
3V0
IGL
Z0FTH
(Calculation)
Z0RTH
(Calculation)
Best Choice
Ground
Directional
Logic
—
+
enable output
Enable
—
+
z0 Calculation
1
2