Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.70 Zone 1 AB Loop Conventional Quadrilateral Phase-Distance Element Logic; Figure 5.71 Zone 2 AB Loop Conventional Quadrilateral Phase-Distance Element Logic

5.90
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Quadrilateral Phase-Distance Elements
Figure 5.71 shows the logic of the Zone 2 quadrilateral phase-distance element
for the AB loop. Fault calculations for BC and CA faults have similar logics.
Figure 5.70 Zone 1 AB Loop Conventional Quadrilateral Phase-Distance
Element Logic
Figure 5.71 Zone 2 AB Loop Conventional Quadrilateral Phase-Distance
Element Logic
IABLFM
0.1 • I
NOM
F32P
CVTBL
XAB1
RABX1
OSB1
67Q1T
FSA
FSB
HSDAGF
HSDBGF
SERCAB
ILOP
SPO
MABDF
xABF
XP1 (setting)
Phase Selection
VPOLV
ENX2AB
32QE
Z50P1
(setting)
IABLFM
0.1 • I
NOM
F32P
XAB2
RABX2
OSB2
67QUBF
FSA
FSB
HSDAGF
HSDBGF
ILOP
SPO
MABDF
xABF
XP2
(setting)
VPOLV
Phase Selection
ENX2AB
32QE