6-2
Close and Reclose Logic
Date Code 20001006
SEL-351 Instruction Manual
See the settings sheet in
Section 9: Setting the Relay
for setting ranges.
Figure 6.1: Close Logic
Set Close
If all the following are true:
•
The unlatch close condition is not asserted (ULCL = logical 0).
•
The circuit breaker is open (52A = logical 0).
•
The reclose initiation condition (79RI) is not making a rising edge (logical 0 to logical 1)
transition.
•
And a close failure condition does not exist (Relay Word bit CF = 0).
Then the CLOSE Relay Word bit can be asserted to logical 1 if either of the following occurs:
•
A reclosing relay open interval times out (qualified by SEL
OGIC
Control Equation setting
79CLS – see Figure 6.2).
•
Or SEL
OGIC
Control Equation setting CL goes from logical 0 to logical 1 (rising edge
transition).
Note
:
CLOSE Command no longer embedded in Close Logic
In previous firmware versions of the SEL-351 Relay, the CLOSE command was embedded
in the close logic in Figure 6.1. The CLOSE command was routed directly into the same
OR logic gate as Reclosing Relay Open Interval Time-out and SEL
OGIC
Control Equation
setting CL.
The CLOSE command is no longer directly embedded in the close logic. This change was
made so that users can supervise the CLOSE command if desired via setting CL.
Summary of Contents for SEL-351
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