6-14 Close and Reclose Logic Date Code 20001006
SEL-351 Instruction Manual
Lockout State
The reclosing relay goes to the Lockout State if any one of the following occurs:
• The shot counter is equal to or greater than the last shot at time of reclose initiation
(e.g., all automatic reclosing attempts are unsuccessful — see Figure 6.6).
• Reclose initiation is unsuccessful because of SELOGIC Control Equation setting 79RIS
[see Reclose Initiate and Reclose Initiate Supervision Settings (79RI and 79RIS,
respectively) later in this subsection].
• The circuit breaker opens without reclose initiation (e.g., an external trip).
• The shot counter is equal to or greater than last shot, and the circuit breaker is open [e.g.,
the shot counter is driven to last shot with SELOGIC Control Equation setting 79DLS
while open interval timing is in progress. See Drive-to-Lockout and Drive-to-Last Shot
Settings (79DTL and 79DLS, respectively) later in this subsection].
• The close failure timer (setting CFD) times out (see Figure 6.1).
• SELOGIC Control Equation setting 79DTL = logical 1 [see Drive-to-Lockout and Drive-
to-Last Shot Settings (79DTL and 79DLS, respectively) later in this subsection].
• The Reclose Supervision Limit Timer (setting 79CLSD) times out (see Figure 6.2 and top
of Figure 6.3).
Note: OPEN Command no longer embedded in Drive-to-Lockout Logic
In previous firmware versions of the SEL-351 Relay (except the original release), the
OPEN command was embedded to drive the reclosing relay to lockout (see Appendix A).
The OPEN command is no longer directly embedded in the reclosing relay logic. It is also
no longer directly embedded in the trip logic (see the Note following Figure 5.2).
This change was made so that users can supervise the OPEN command if desired (see the
example in the Note following Figure 5.2).
The OPEN command is now included in the reclosing relay logic via the factory SELOGIC
Control Equation settings:
79DTL = … + OC (drive-to-lockout)
Relay Word bit OC asserts for execution of the OPEN Command. See OPE Command
(Open Breaker) in Section 10: Serial Port Communications and Commands for more
information on the OPEN Command. Also, see Drive-to-Lockout and Drive-to-Last Shot
Settings (79DTL and 79DLS, respectively) later in this subsection.
If the OPEN command is set to trip (TR = … + OC; see Note following Figure 5.2), then
the following reclosing relay SELOGIC Control Equation settings should also be made
(presuming that an OPEN command trip should not initiate reclosing):
79RI = TRIP (reclose initiate)
79DTL = … + OC (drive-to-lockout)
This is how the SEL-351 Relay is set at the factory.
Courtesy of NationalSwitchgear.com
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