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5.26
SEL-421 Relay
Instruction Manual
Date Code 20171021
Protection Functions
Pole-Open Logic
SPOC
C-Phase open
SPO
One or two poles open
3PO
All three poles open
27APO
A-Phase undervoltage—pole open
27BPO
B-Phase undervoltage—pole open
27CPO
C-Phase undervoltage—pole open
Table 5.26
Pole-Open Logic Relay Word Bits (Sheet 2 of 2)
Name
Description
Summary of Contents for SEL-421-4
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