GE Multilin 850 Instruction Manual page 493

CHAPTER 4: SETPOINTS
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850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
UV ON OTHER SOURCE
Range: Off, Any FlexLogic operand
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to block transfer for undervoltage on the other source. Typically, "line" (source)
Instantaneous Undervoltage protection on the other source wired as digital input or sent
by communication, is used.
DELAY OTHER SOURCE
Range: 0.000 to 6000.000 s in steps of 0.001 s
Default: 3.000 s
The setting provides selection of a time delay that prevents Transfers that can otherwise
be caused by a non-simultaneous return of source voltages after a loss of both sources.
It establishes an interval from the return of the second source during which a Transfer
cannot be initiated.
INST UV ON THIS SOURCE
Range: Off, Any FlexLogic operand
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to block the Transfer after reset of the overcurrent elements on this source.
Typically, "line" (source) Instantaneous Undervoltage protection element is used.
The same operand has to be used to block transfer initiation (setting UV ON OTHER
SOURCE for Incomer 2 relay) on the other relay as this source is "the other source is
experiencing low voltage" for the other relay.
DELAY THIS SOURCE
Range: 0.000 to 6000.000 s in steps of 0.001 s
Default: 1.000 s
The setting provides selection of a time interval from the reset of the overcurrent
elements selected on this source during which the low voltage instantaneous is allowed
to block transfer.
FAULT CURRENT PICKUP IN 1 (to 6)
Range: Off, Any FlexLogic operand
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to block transfer, while a fault, which can cause a severe voltage dip, is present on
the load side of the breaker. Typically, Phase and Neutral Time and Instantaneous
Overcurrent protection Pickup elements are used.
This fault is cleared by Time Overcurrent protection on the Incomer or an upstream
breaker. If Device 50P is set properly, during this event it allows a low voltage Timed
Undervoltage function to time out before the Inverse Time Phase Overcurrent operates,
but still prevent Transfer initiation. The 50P element is set above the maximum current
caused by either the bus motor contribution to an upstream fault, or the maximum current
during low voltage conditions. The 50N element is set to detect arcing ground faults, but
allow permitted unbalances.
BLOCK TRANSFER
Range: Off, Any FlexLogic operand
Default: Off
The Transfer is blocked when the selected operand is asserted.
CONTROL
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