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4.17
Date Code 20171021
Instruction Manual
SEL-421 Relay
Front-Panel Operations
One-Line Diagrams
The Bay Control indicates the status of breakers in the one-line diagrams. The
setting EPOLDIS, Enable Single-Pole Discrepancy Logic, controls the behavior.
If the breaker is a single-pole type, Global Setting BK
n
TYP = 1, where
n
is 1 or 2,
the breaker status will be determined based on the EPOLDIS setting. If
EPOLDIS = Y, then the breaker status is indicated by the Relay Word bits 52ACL
n
,
52BCL
n
, and 52CCL
n
, which check for current to determine the breaker status.
This setting is useful to identify a pole discrepancy, where a pole may not open
but the other two do. In this case, the breaker status would display a pole discrep-
ancy screen as shown below in
. If EPOLDIS = N, the single-pole dis-
crepancy logic is disabled, and the breaker status will follow the 52
n
CLSM
SEL
OGIC
setting.
Figure 4.13
Configuring PB1_HMI for Direct Bay Control Access
Summary of Contents for SEL-421-4
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