Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.65 Zones 3, 4, and 5 Mho Phase-Distance Element Logic Diagram

5.84
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Mho Phase-Distance Elements
Figure 5.65 shows the Zone 3, 4 and 5 phase-distance element logic. Other fault
calculations (BC, CA) have similar logic. In Figure 5.65, Output ZnP is the OR
combination of the following Zone n (n = 3, 4, 5) elements (ØØ = AB, BC, CA):
➤ Conventional mho elements (MØØn)
➤ Conventional quadrilateral elements (XØØn)
Figure 5.65 Zones 3, 4, and 5 Mho Phase-Distance Element Logic Diagram
—
+
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
Setting
32SPOF
IABLFM
DIRn := F
F32P
SPOA
SPOB
R32P
32SPOR
SPOC
VPOLV
ILOP
OSBA
OSBn
67QUBF
67QUBR
—
+
—ZnMP
(setting)
—
+
ZnMP
(setting)
+
—
IABL
—0.1 • I
NOM
+
—
0.1 • I
NOM
mABF
FSA
FSB
MABDF
MABn
MBCn
XBCn
XCAn
MCAn
XABn
Relay
Word
Bit
ZnP
Relay
Word
Bits
MnP