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5.79
Date Code 20171021
Instruction Manual
SEL-421 Relay
Protection Functions
Quadrilateral Ground-Distance Elements
Figure 5.61
Zone 2 Quadrilateral Distance Element Logic Diagram
Relay
Word
Bits
Relay
Word Bits
Relay
Word
Bit
(Setting)
(Setting)
XAG2
XGPOL := IG
32VE
32QE
32GF
XGPOL := I2
IAL
IGL
xAGF < XG2
—RG2 < rAGF < RG2
0.1 • I
NOM
FSA
SPO
B- and C-Phase Logic is Similar
xAGF is the A-Phase-to-Ground Forward Reactance Calculation
rAGF is the A-Phase-to-Ground Forward Resistance Calculation
+
—
+
—
| 3IA2LF |
+
—
3PO
ILOP
VPOLV
ARESE = N
ENX2AG
Summary of Contents for SEL-421-4
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