3.22
SEL-551 Relay Instruction Manual Date Code 20110408
Relay Elements and Logic
Reclosing Relay
Defeat the Close
Logic
If SELOGIC control equation setting 52A is set with numeral 0 (52A = 0), then
the close logic is inoperable. Also, the reclosing relay is rendered nonexistent
(see Reclosing Relay on page 3.22).
Program an Output
Contact for Closing
In the factory settings, the resultant of the close logic in Figure 3.14 is routed
to output contact OUT2 with the following SEL
OGIC control equation:
OUT2 = CLOSE
See Output Contacts on page 3.39 for more information on programming
output contacts.
Reclosing Relay
Note that the output of the reclosing relay logic (Reclosing Relay Open
Interval Time-Out) is an input into the close logic in Figure 3.14. The CLOSE
Relay Word bit can be assigned to an output contact and provide automatic
reclosing, in addition to closing via the CLOSE command or the SEL
OGIC
control equation setting CL. Up to four (4) automatic reclose attempts (shots)
can be made.
Reclosing Relay
States and General
Operation
Figure 3.15 explains in general the different states of the reclosing relay and
its operation.
Figure 3.15 Reclosing Relay States and General Operation
Reset State
Reclose Cycle StateLockout State
All Automatic
Reclosing Attempts
Unsuccessful
Unsuccessful
Reclose Initiation
Other Lockout Conditions
Power Up
Reset
Timer
Times
Out
Reset
Timer
Times
Out
Other
Lockout
Conditions
Unsuccessful
Reclose
Initiation
Successful
Reclose
Initiation
Successful
Reclose
Initiation
Maintained
Lockout
Condition
The circuit breaker has been closed
for a qualifying reset time. The SEL-551
is ready to go through an automatic
reclosing sequence in the reclose cycle
state if the circuit breaker trips open
and reclose initiation is successful.
Relay Word bit 79RS = logical 1
Front-panel RESET LED illuminated
The SEL-551 automatically recloses the
circuit breaker after each successful
reclose initiation and corresponding set
open interval time.
Relay Word bit 79CY = logical 1
There is no front-panel LED that
corresponds to the reclose cycle state.
All automatic reclosing attempts are
unsuccessful, reclose initiation is unsuccessful,
other lockout conditions occur, or the SEL-551
powers up. The relay returns to the reset state
after the circuit breaker is closed, the reset
timer times out, and there are no maintained
lockout conditions.
Relay Word bit 79LO = logical 1
Front-panel LOCKOUT LED illuminated
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