6.2
SEL-311C Relay Instruction Manual Date Code 20060320
Close and Reclose Logic
Close Logic
Close Logic
The close logic in Figure 6.1 provides flexible circuit breaker closing/
automatic reclosing with SEL
OGIC control equation settings:
52A (breaker status)
CL (close conditions, other than automatic reclosing)
ULCL (unlatch close conditions, other than circuit breaker status, close
failure, or reclose initiation)
and setting:
CFD (Close Failure Time)
See Other Settings on page SET.14 for setting ranges.
q From Figure 6.2.
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.
➤ 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 SELOGIC control equation setting CL goes from logical 0 to
logical 1 (rising edge transition).
52A
Breaker Status
Close Failure
Timer
CF
Rising Edge Detect
ULCL
CFD = OFF
Reclosing Relay Open
Interval Time-Out
(qualified by 79CLS)
79RI
52A
Reclose Initiate
Close
Conditions
(other than
automatic
reclosing)
q
Unlatch Close
(If setting CFD = OFF, the Close
Failure Timer is inoperative
and does not time limit the
CLOSE 0utput condition)
CL
SELOGIC
Settings
CLOSE
Relay
Word
Bits
Pulses (logical 1)
for one processing
interval if Close
Failure Timer
times out (drives
reclosing relay to
lockout)
Close Failure
CFD
0
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