6.7
Date Code 20080213 Instruction Manual SEL-351A Relay
Close and Reclose Logic
Reclose Supervision Logic
With this setting, the logic in the top of Figure 6.2 is operative. When an open
interval times out, the SEL
OGIC control equation reclose supervision setting
79CLS is checked just once.
If 79CLS is asserted to logical 1 at the instant of an open interval time-out,
then the now-qualified open interval time-out will propagate onto the final
close logic in Figure 6.1 to automatically reclose the circuit breaker.
If 79CLS is deasserted to logical 0 at the instant of an open interval time-out,
the following occurs:
➤ No automatic reclosing takes place.
➤ Relay Word bit RCSF (Reclose Supervision Failure indication)
asserts to logical 1 for one processing interval.
➤ If setting E79 = 1, 2, 3, or 4, the reclosing relay is driven to
Lockout State.
➤ If setting E79 = C1, C2, C3, or C4, the reclosing relay
increments the shot counter and starts timing on the next open
interval. This operation emulates a rotating drum timer style
reclosing relay—going onto the next open interval time and
reclose opportunity if supervising conditions for the present
reclose opportunity are not true. If the reclosing relay
increments to the last shot value (no more open intervals left;
see Figure 6.6 and Table 6.3), the reclosing relay is then driven
to the Lockout State.
See Factory Settings Example on page 6.9 and Additional Settings Example 1
on page 6.9.
For a Few, Unique Applications (Bottom of Figure 6.2 and Figure 6.3)
For a few unique applications, the Reclose Supervision Limit Time setting is
not set equal to zero cycles, e.g.,
79CLSD = 60.00
With this setting, the logic in the bottom of Figure 6.2 is operative. When an
open interval times out, the SEL
OGIC control equation reclose supervision
setting 79CLS is then checked for a time window equal to setting 79CLSD.
If 79CLS asserts to logical 1 at any time during this 79CLSD time window,
then the now-qualified open interval time-out will propagate onto the final
close logic in Figure 6.1 to automatically reclose the circuit breaker.
If 79CLS remains deasserted to logical 0 during this entire 79CLSD time
window, when the time window times out, the following occurs:
➤ No automatic reclosing takes place.
➤ Relay Word bit RCSF (Reclose Supervision Failure indication)
asserts to logical 1 for one processing interval.
➤ If setting E79 = 1, 2, 3, or 4, the reclosing relay is driven to
Lockout State.
➤ If setting E79 = C1, C2, C3, or C4, the reclosing relay
increments the shot counter and starts timing on the next open
interval. This operation emulates a rotating drum timer style
reclosing relay—going onto the next open interval time and
reclose opportunity if supervising conditions for the present
reclose opportunity are not true. If the reclosing relay
Courtesy of NationalSwitchgear.com
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