Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.25 Zero-Sequence Current-Polarized Directional Element Logic; Figure 5.26 Ground Directional Element Output Logic Diagram

5.42
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Ground Directional Element
q From Figure 5.20 ; w From Figure 5.22
Figure 5.25 Zero-Sequence Current-Polarized Directional Element Logic
SPO
Relay
Word
Bits
F32I
(Forward)
R32I
(Reverse)
Relay
Word
Bits
32IE
Relay
Word
Bits
50GR
Relay
Word
Bit
ILOP
50GF
IP
IGL
32IFTH
(Calculation)
32IRTH
(Calculation)
Best Choice
Ground
Directional
Logic
—
+
enable output
Enable
—
+
32I Calculation
1
2
Figure 5.26 Ground Directional Element Output Logic Diagram
Ta b l e 5 . 37 Ref e re n ce Ta b le fo r
Figure 5.23 , Figure 5.24 , and Figure 5.25
(Sheet 1 of 2)
Name Description
z2 Negative-sequence voltage-polarized directional element impedance calculation
Z2FTH Negative-sequence voltage-polarized directional element forward threshold
calculation
Z2RTH Negative-sequence voltage-polarized directional element reverse threshold
calculation
z0 Zero-sequence voltage-polarized directional element impedance calculation
50QR
50GR
R32I
R32V
R32QG
F32I
32SPOF
32SPOR
F32V
F32QG
32IE
LOP
ELOP = Y
50QF
50GF
32GF
reset
32GR
0
.75
CYC
0
.75
CYC
reset
HSDGF
HSDGR