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5.83
Date Code 20171021
Instruction Manual
SEL-421 Relay
Protection Functions
Mho Phase-Distance Elements
shows the Zone 2 phase-distance element logic. The other fault cal-
culations (BC, CA) have similar logic. In
, Output Z2P is the OR
combination of the following Zone 2 elements (ØØ = AB, BC, CA):
➤
Conventional mho elements (MØØ2)
➤
Conventional quadrilateral elements (XØØ2)
Figure 5.64
Zone 2 Mho Phase-Distance Element Logic Diagram
—
+
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
—
+
—
+
IABLFM
MABDF
mABF
Z2MP
(setting)
F32P
32SPOF
SPOA
67QUBF
SPOB
FSA
FSB
SPOC
VPOLV
ILOP
OSBA
OSB2
0.1 • I
NOM
MAB2
MBC2
XBC2
XCA2
MCA2
XAB2
Relay
Word
Bit
Z2P
Relay
Word
Bits
M2P
Summary of Contents for SEL-421-4
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