GE F60 Instruction Manual page 488

MONITORING ELEMENTS
internal faults on the protected line are identified, the blocking action can be removed through
This is done to cope with evolving faults when an external fault is followed by an internal fault. Do not set the
longer than the fastest possible trip time for faults on an adjacent line so that the extended blocking action
PICKUP DELAY
can be established. Take into account the pickup time of the reverse-looking elements of the scheme. Do not set the delay
too short, in order to avoid locking up a spurious reverse fault indication that can occur during internal fault conditions.
TRANS BLOCK RESET DELAY
coping with the exposure of the overreaching protection functions to current reversal conditions (see also the
). Set this delay long enough to cope with transient conditions including not only current reversals but also
PICKUP DELAY
spurious negative and zero-sequence currents occurring during breaker operations.
DCB3 SEAL-IN DELAY
DCB3 SEAL-IN DELAY
— This setting defines the FlexLogic operand of a protection element to identify forward faults on the
DCB3 DIR FWD1-3
protected line, and thus, for initiating operation of the scheme. Good directional integrity is the key requirement for an
over-reaching forward-looking protection element.
Even though any FlexLogic operand can be used as DIR FWD, enabling the user to combine responses of various
protection elements or to apply extra conditions through FlexLogic equations, DIR FWD entries are primarily meant to be
the output operand from the Negative-Sequence Directional FWD IOC, Neutral Directional FWD IOC, and the forward-
looking distance over-reaching elements.
— This setting defines the FlexLogic operand of a protection element to identify reverse faults, and thus, to
DCB3 DIR REV1-3
initiate the blocking signal. Reverse-looking directional overcurrent protection elements or reverse-looking distance
elements can be used as DIR REV.
Even though any FlexLogic operand can be used as DIR REV, enabling the user to combine responses of various protection
elements or to apply extra conditions through FlexLogic equations, DIR REV entries are primarily meant to be the output
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operand from the Negative-Sequence Directional REV IOC, Neutral Directional REV IOC, non-directional IOC, or reverse-
looking distance elements.
The selected protection element (or elements in combination) need to be coordinated with the selection of DIR FWD. For all
the forward external faults seen by an element used as DIR FWD at one end of the line, the reverse-looking element used
as DIR REV at the other end needs to pick up and provide a blocking signal.
DCB3 FORCE TX STOP1-2
faults on the protected line, and thus, to stop the blocking signal. Typically, forward-looking under-reach protection
elements are used as FORCE TX STOP.
— This setting selects the FlexLogic operands to represent the receive signals for the scheme. Contact inputs
DCB3 RX
interfacing with a signaling system(s) are used typically.
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— This setting defines a transient blocking mechanism embedded in the blocking scheme for
— The output FlexLogic operand
defines a minimum guaranteed duration of the
— This setting defines the FlexLogic operand of a protection element that is used to identify internal
(DCB3 OP) is produced according to the Blocking scheme logic. The
pulse.
DCB3 OP
F60 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
inputs.
FORCE TX STOP1-2
TRANS BLOCK
TRANS BLOCK