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 SEL
OGIC
Control Equation setting
CL is the only logic input that can set the CLOSE Relay Word bit.
In SEL
OGIC
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
SEL
OGIC
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
.
SEL
OGIC
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 SEL
OGIC
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 SEL
OGIC
Control Equation setting 52A (circuit
breaker status) is available as Relay Word bit 52A. This makes for convenience in setting other
SEL
OGIC
Control Equations. For example, if the following setting is made:
52A = IN1
(52a auxiliary contact wired to input IN1)
Summary of Contents for SEL-351
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