Date Code 20001006
Close and Reclose Logic
6-1
SEL-351 Instruction Manual
SECTION 6: CLOSE AND RECLOSE LOGIC
This section is made up of three subsections:
Close Logic
This subsection describes the final logic that controls the close output contact (e.g.,
OUT2 = CLOSE). This output contact closes the circuit breaker for automatic
reclosures and other close conditions (e.g., manual close initiation via serial port or
optoisolated inputs).
If automatic reclosing is not needed, but the SEL-351 Relay is to close the circuit breaker
for other close conditions (e.g., manual close initiation via serial port or optoisolated
inputs), then this subsection is the only subsection that needs to be read in this section
(particularly the description of SEL
OGIC
®
Control Equation setting CL).
Reclose Supervision Logic
This subsection describes the logic that supervises automatic reclosing when an open
interval time times out – a final condition check right before the close logic asserts the
close output contact.
Reclose Logic
This subsection describes all the reclosing relay settings and logic needed for automatic
reclosing (besides the final close logic and reclose supervision logic described in the
previous subsections).
The reclose enable setting, E79, has setting choices N, 1, 2, 3, and 4. Setting E79 = N
defeats the reclosing relay. Setting choices 1 through 4 are the number of desired
automatic reclosures.
Note:
Setting E79 = N defeats the reclosing relay, but does not defeat the ability of the
close logic described in the first subsection (Figure 6.1) to close the circuit
breaker for other close conditions via SEL
OGIC
Control Equation setting CL
(e.g., manual close initiation via serial port or optoisolated inputs).
C
LOSE
L
OGIC
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)
Summary of Contents for SEL-351
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