6.8
SEL-351A Relay Instruction Manual Date Code 20080213
Close and Reclose Logic
Reclose Supervision Logic
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.
The logic in the bottom of Figure 6.2 is explained in more detail in the
following text.
Set Reclose Supervision Logic (Bottom of Figure 6.2)
Refer to the bottom of Figure 6.2. If all the following are true:
➤ The close logic output CLOSE (also see Figure 6.1) is not
asserted (Relay Word bit CLOSE = logical 0).
➤ The reclosing relay is not in the Lockout State (Relay Word bit
79LO = 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.
➤ The Reclose Supervision Limit Timer is not timed out (Relay
Word bit RCSF = logical 0).
then a reclosing relay open interval time-out seals in Figure 6.2. Then, when
79CLS asserts to logical 1, the sealed-in reclosing relay open interval time-out
condition will propagate through Figure 6.2 and on to the close logic in
Figure 6.1.
Unlatch Reclose Supervision Logic (Bottom of Figure 6.2)
Refer to the bottom of Figure 6.2. If the reclosing relay open interval time-out
condition is sealed-in, it stays sealed-in until one of the following occurs:
➤ The close logic output CLOSE (also see Figure 6.1) asserts
(Relay Word bit CLOSE = logical 1).
➤ The reclosing relay goes to the Lockout State (Relay Word bit
79LO = logical 1).
➤ The circuit breaker closes (52A = logical 1).
➤ The reclose initiation condition (79RI) makes a rising-edge
(logical 0 to logical 1) transition.
➤ SELOGIC control equation setting 79CLS asserts (79CLS =
logical 1).
➤ Or the Reclose Supervision Limit Timer times out (Relay Word
bit RCSF = logical 1 for one processing interval).
The Reclose Supervision Limit Timer is inoperative if setting 79CLSD = OFF.
With 79CLSD = OFF, reclose supervision condition 79CLS is not time
limited. When an open interval times out, reclose supervision condition
79CLS is checked indefinitely until one of the other above unlatch conditions
comes true.
The unlatching of the sealed-in reclosing relay open interval time-out
condition by the assertion of SEL
OGIC control equation setting 79CLS
indicates successful propagation of a reclosing relay open interval time-out
condition on to the close logic in Figure 6.1.
See Additional Settings Example 2 on page 6.10.
Courtesy of NationalSwitchgear.com
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