6-4 Close and Reclose Logic Date Code 20001006
SEL-351 Instruction Manual
CFD = 60.00 cycles
See the settings sheets at the end of Section 9: Setting the Relay for setting ranges.
Set Close
If the Reclosing Relay Open Interval Time-Out logic input at the top of Figure 6.1 is ignored
(reclosing is discussed in detail in a following subsection), then SELOGIC Control Equation setting
CL is the only logic input that can set the CLOSE Relay Word bit.
In SELOGIC Control Equation setting CL = CC + LB4
• Local bit LB4 operates as a manual close switch via the front panel. See Local Control
Switches in Section 7: Inputs, Outputs, Timers, and Other Control Logic and Local
Control in Section 11: Front-Panel Interface for more information on local control.
• Relay Word bit CC asserts for execution of the CLOSE Command. See CLO Command
(Close Breaker) in Section 10: Serial Port Communications and Commands for more
information on the CLOSE Command.
Unlatch Close
SELOGIC Control Equation setting ULCL is set with the TRIP Relay Word bit. This prevents the
CLOSE Relay Word bit from being asserted any time the TRIP Relay Word bit is asserted (TRIP
takes priority). See Trip Logic in Section 5: Trip and Target Logic.
SELOGIC Control Equation setting 52A is set with optoisolated input IN1. Input IN1 is connected
to a 52a circuit breaker auxiliary contact. When a closed circuit breaker condition is detected, the
CLOSE Relay Word bit is deasserted to logical 0. Setting 52A can handle a 52a or 52b circuit
breaker auxiliary contact connected to an optoisolated input (see Optoisolated Inputs in Section 7:
Inputs, Outputs, Timers, and Other Control Logic for more 52A setting examples).
With setting CFD = 60.00 cycles, once the CLOSE Relay Word bit asserts, it remains asserted at
logical 1 no longer than a maximum of 60 cycles. If the Close Failure Timer times out, Relay
Word bit CF asserts to logical 1, forcing the CLOSE Relay Word bit to logical 0.
Defeat the Close Logic
If SELOGIC Control Equation circuit breaker auxiliary setting 52A is set with numeral 0
(52A = 0), then the close logic is inoperable. Also, the reclosing relay is defeated (see Reclosing
Relay later in this section).
Circuit Breaker Status
Refer to the bottom of Figure 6.1. Note that SELOGIC Control Equation setting 52A (circuit
breaker status) is available as Relay Word bit 52A. This makes for convenience in setting other
SELOGIC Control Equations. For example, if the following setting is made:
52A = IN1 (52a auxiliary contact wired to input IN1)
Courtesy of NationalSwitchgear.com
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