GE 845 Instruction Manual page 418

CONTROL
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DEAD SOURCE PERM
Range: Disabled, LB & DL, DB & LL, DB & DL, DB OR DL, DB XOR DL
Default: Disabled
The setpoint selects the combination of dead and live sources that bypass the
synchronism check function and permit the breaker to be closed when one or both of
the two voltages (Bus Voltage or/and Line Voltage) are below the maximum voltage
threshold. A dead or live source is declared by monitoring the voltage level. Six options
are available.
The voltage levels that determine whether a source is dead or live are configurable in
the four setpoints following this one.
The DEAD SOURCE PERMISSION range is as follows:
"Disabled": Dead source permissive is disabled.
"LB & DL": Live Bus AND Dead Line."DB & LL": Dead Bus AND Live Line.
"DB & DL": Dead Bus AND Dead Line.
"DB OR DL": Dead Bus OR Dead Line.
"DB XOR DL": Dead Bus XOR Dead Line (one source is Dead and one is Live).
For an application where the breaker is located on radial feeders, or line is powered by one
source only, the DEAD SOURCE PERM setpoint shall not be disabled.
LIVE BUS VOLTS MIN
Range: 0.00 to 1.50 x VT in steps of 0.01 x VT
Default: 0.80 x VT
The setpoint establishes a minimum voltage magnitude for the Bus Voltage. Above this
magnitude, the Bus Voltage input used for Synchrocheck is considered "Live" or
energized.
LIVE LINE VOLTS MIN
Range: 0.00 to 1.50 x VT in steps of 0.01 x VT
Default: 0.80 x VT
The setpoint establishes a minimum voltage magnitude for the Line Voltage. Above this
magnitude, the Line Voltage input used for Synchrocheck is considered "Live" or
energized.
DEAD BUS VOLTS MAX
Range: 0.00 to 1.50 x VT in steps of 0.01 x VT
Default: 0.20 x VT
The setpoint establishes a maximum voltage magnitude for the Bus Voltage. Below this
magnitude, the Bus Voltage input used for Synchrocheck is considered "Dead" or de-
energized.
DEAD LINE VOLTS MAX
Range: 0.00 to 1.50 x VT in steps of 0.01 x VT
Default: 0.20 x VT
This setpoint establishes a maximum voltage magnitude for the Line Voltage. Below this
magnitude, the Line Voltage input used for Synchrocheck is be considered "Dead" or de-
energized.
BLOCK
Range: Off, Any operand from the list of FlexLogic operands
Default: Off
The Synchrocheck is blocked when the selected operand is asserted. Typically 52a (the
circuit breaker closed) contact is used to block Synchrocheck (Synchrocheck is needed
only when the circuit breaker is open). Synchrocheck can be also blocked when the relay
is tripping.
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS