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5.129
Date Code 20171021
Instruction Manual
SEL-421 Relay
Protection Functions
Permissive Overreaching Transfer Tripping Scheme
27CWI
C-Phase undervoltage condition
WFC
Weak-infeed detected
KEY1
Transmit permission to single-pole trip
KEY3
Transmit permission to three-pole trip
Figure 5.93
Permissive Trip Receiver Logic Diagram
Table 5.73
POTT Relay Word Bits (Sheet 2 of 2)
Name
Description
PT
To POTT
Logic
Relay
Word Bit
PTDRX
Relay
Word Bit
PTDIR
Relay
Word Bit
ECOMM := POTT
Setting
ECOMM := DCUB1
ECOMM := DCUB2
PT1
PT2
ECOMM := POTT2
Setting
EPTDIR := Y
Setting
Setting
Setting
Control Input
Assignments
Summary of Contents for SEL-421-4
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