Schweitzer Engineering SEL-351P, Quick Start Manual

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11-6 Additional Front-Panel Interface Details Date Code 990215
SEL-351P Manual Técnico
RETURN position (local bit LB3 deasserts to logical 0 again).
On the display, the MANUAL TRIP switch is shown to be in the TRIP position for 2 seconds
(long enough to be seen), and then it returns to the RETURN position:
MANUAL TRIP
←→
Position: RETURN
The MANUAL CLOSE switch is an OFF/MOMENTARY type switch, like the MANUAL TRIP
switch, and operates similarly.
See Local Control Switches in Section 7: Inputs, Outputs, Timers, and Other Control Logic
for details on how local bit outputs LB3 and LB4 are set in SEL
OGIC
Control Equation settings
to respectively trip and close a circuit breaker.
Local Control State Retained When Relay Deenergized
Local bit states are stored in nonvolatile memory, so when power to the relay is turned off, the
local bit states are retained.
For example, suppose the local control switch with local bit output LB1 is configured as an
ON/OFF type switch (see Figure SECTION 11: .1). Additionally, suppose it is used to
enable/disable reclosing. If local bit LB1 is at logical 1, reclosing is enabled:
If power to the relay is turned off and then turned on again, local bit LB1 remains at logical 1,
and reclosing is still enabled. This is akin to a traditional panel, where enabling/disabling of re-
closing and other functions is accomplished by panel-mounted switches. If dc control voltage to
the panel is lost and then restored again, the switch positions are still in place. If the reclosing
switch is in the enable position (switch closed) before the power outage, it will be in the same
position after the outage when power is restored.
See Drive-to-Lockout and Drive-to-Last Shot Settings (79DTL and 79DLS,
respectively) in Section 6: Close and Reclose Logic for more information on setting
79DTL.