Schweitzer Engineering Laboratories SEL-311L, Instruction Manual, Page: 219 / 734

Date Code 20010625 Close and Reclose Logic 6-1
SEL-311L Instruction Manual
SECTION 6: CLOSE AND RECLOSE LOGIC
O
VERVIEW
This section is made up of three subsections:
Close Logic
This subsection describes the final logic that controls the close output contact (e.g.,
OUT103 = 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-311L 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. The default
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)