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CONTROL
4–338
INC 2 TRANSFORMER LOCKOUT
Range: Off, Any operand from the list of FlexLogic operands
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to initiate Transfer for substations with transformers and transformer fault lockout
devices. Typically, an auxiliary contact from the lockout relay (86T) is fed to one of the
850 contact inputs and set as "Source Transformer Lockout".
INC 2 SOURCE TRIP
Range: Off, Any operand from the list of FlexLogic operands
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to initiate Transfer for substations with an upstream circuit breaker equipped with
a trip signal (Device 94). The signal triggering the Transfer sequence can be originated
from the upstream protection. Typically, an auxiliary contact from the tripping device
(94) is fed to one of the 850 contact inputs and set as "Source Trip".
TIMED UV ON THIS SOURCE
Range: Off, Any operand from the list of FlexLogic operands
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to initiate Transfer for loss of source. Typically, a trip from "line" (source) Time
Undervoltage protection element is used to initiate Transfer.
BLOCK TRIP ON DOUBLE LOSS
Range: Enabled, Disabled
Default: Disabled
The setpoint selects the required scheme operation in the event of a simultaneous loss
of both Source 1 and Source 2. If it is desired to have both of the Incomers trip on Time
Undervoltage when this occurs, select "Disabled". If it is desired to prevent the Incomers
from tripping on Time Undervoltage when this occurs, select "Enabled". With either
selection, a transfer-initiated close of the bus tie breaker is not allowed.
INC 2 BKR CLOSED
Range: Off, Any operand from the list of FlexLogic operands
Default: Off
The setpoint selects the FlexLogic operand, digital input, virtual input or remote input
used to track a breaker-closed state. Typically, a 52a auxiliary breaker contact- or
breaker-closed state from the Breaker Detection control element is used to indicate the
close state of the breaker, thus preventing the two incoming power systems from being
connected in parallel, while at the same time permitting Transfer logic.
UV ON OTHER SOURCE
Range: Off, Any operand from the list of FlexLogic operands
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.
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
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