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345 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
S4 CONTROLS
CHAPTER 6: SETPOINTS
Lockout (86)
The purpose of the Lockout function is to prevent unwanted closing of the breaker after
being tripped by the operation of a protection element. To use the Lockout feature from a
345 relay, first program a Logic Element using the "Lockout OP" operand. The Logic
Element shall be then set to drive an output relay with an NC contact connected in series
with an outside output relay normally used for closing the breaker. The full lockout
sequence is then the following: a protection operates, sends trip command to the breaker
and the breaker opens. The same protection is set to trigger Lockout. The programmed
Logic Element operates and drives an output relay with an NC contact connected in series
with a relay used for breaker closing. The NC contact opens and blocks the closing to the
breaker, until the lockout is reset.
The lockout block is removed upon a Lockout Reset signal sent to the relay. The Lockout
Reset can be initiated either by pressing the relay pushbutton RESET (after it is enabled to
perform Lockout resets), or by any contact, virtual, or remote input selected under the
Lockout Reset setpoint.
FUNCTION
Range: Disabled, Enabled
Default: Disabled
For details see
Common setpoints
.
INPUT 1(10)
Range: Off, Any Logic Operand
Default: Off
This setting selects an operand from the list of logic operands. The assertion of the
selected operand triggers lockout. Ten trigger input setpoints are provided.
LOCKOUT SUPERVISION
Range: Off, Any logic operand
Default: Off
This setting provides selection of any logic operand to supervise the initiation of lockout
state. As an example the open status of the breaker/breakers could be used for lockout
supervision.
LOCKOUT RESET
Range: Off, Any Logic Operand
Default: Off
This setting provides selection of any logic operand from the list of operands for
resetting the breaker lockout condition.
RESET FROM PB RESET
Range: Disabled, Enabled
Default: Disabled
If Enabled, pressing the front panel Reset pushbutton resets the Lockout. Otherwise,
when Disabled, pressing the Reset PB sends a common reset which does not reset the
Lockout.
BLOCK RESET LOCKOUT
Range: Off, Any Logic Operand
Default: Any Trip
This setting provides selection of any logic operand to block the reset action of the
lockout state. Usually if there is a presence of a trip condition, the reset command will
not be executed. The default value is selected as "Any Trip" operand.
Summary of Contents for 345
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