6.14
SEL-351A Relay Instruction Manual Date Code 20080213
Close and Reclose Logic
Reclosing Relay
➤ Reclose initiation is unsuccessful because of SELOGIC control
equation setting 79RIS [see Reclose Initiate and Reclose
Initiate Supervision Settings (79RI and 79RIS, respectively) on
page 6.19].
➤ 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. [For instance, the shot counter could be
driven to last shot with SEL
OGIC 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) on page 6.21.]
➤ 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)].
➤ The Reclose Supervision Limit Timer (setting 79CLSD) times
out (see Figure 6.2 and top of Figure 6.3) and the reclose
enable setting, E79, has setting choices 1, 2, 3, or 4.
➤ A new reclose initiation occurs while the reclosing relay is
timing on an open interval (e.g., flashover in the tank while
breaker is open).
Relay Word bit OC asserts for execution of the OPEN command. See OPE
Command (Open Breaker) on page 10.35 for more information on the OPEN
command. Also, see Drive-to-Lockout and Drive-to-Last Shot Settings
(79DTL and 79DLS, respectively).
If the OPEN command is set to trip (TR = … + OC; see Note following
Figure 5.2), then the following reclosing relay SEL
OGIC 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-351A is set at the factory.
Reclosing Relay
States and Settings/
Setting Group
Changes
If individual settings are changed for the active setting group or the active
setting group is changed, all of the following occur:
➤ The reclosing relay remains in the state it was in before the
settings change.
➤ The shot counter is driven to last shot (last shot corresponding
to the new settings; see discussion on last shot that follows).
➤ The reset timer is loaded with reset time setting 79RSLD (Reset
Timer on page 6.17).
If the relay happened to be in the Reclose Cycle State and was timing on an
open interval before the settings change, the relay would be in the Reclose
Cycle State after the settings change, but would immediately go to the
Lockout State. This is because the breaker is open, and the relay is at last shot
after the settings change, so no more automatic reclosures are available.
NOTE: The OPEN command is
included in the reclosing relay logic
via the factory SEL
OGIC control
equation settings:
79DTL = … + OC (drive-to-lockout)
Courtesy of NationalSwitchgear.com
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