GE L90 Instruction Manual page 617

CHAPTER 5: SETTINGS
Even though any FlexLogic operand can be used as
various protection elements or to apply extra conditions through FlexLogic equations,
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 that is used for identifying
BLK1 SCHME DIR REV1-3
reverse faults, and thus, for initiating the blocking signal. Reverse-looking directional overcurrent protection elements or
reverse-looking distance elements can be used as
Even though any FlexLogic operand can be used as
protection elements or to apply extra conditions through FlexLogic equations,
meant to be the output operand from the Negative-Sequence Directional REV IOC, Neutral Directional REV IOC, non-
directional IOC, or reverse-looking distance elements.
Coordinate the selected protection element (or elements in combination) with the selection of DIR FWD. For all the forward
external faults seen by an element used as
at the other end picks up and provides a blocking signal.
BLK1 SCHME DIR REV
— This setting defines the FlexLogic operand of a protection element that is used for identifying
BLK1 FORCE TX STOP1-2
internal faults on the protected line, and thus, for stopping the blocking signal. Typically forward-looking under-reach
distance elements are used as
5.8.12.9 Directional comparison unblocking
SETTINGS  CONTROL ELEMENTS  PILOT SCHEMES  DCUB SCHEME
 DCUB SCHEME

L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
BLK1 SCHME DIR FWD
BLK1 SCHME DIR REV
BLK1 SCHME DIR REV
BLK1 SCHME DIR FWD
.
BLK1 FORCE TX STOP
Figure 5-222: Directional comparison blocking1 scheme logic
DCUB SCHEME

FUNCTION: Disabled
enabling the user to combine responses of
BLK1 SCHME DIR FWD
.
enabling the user to combine responses of various
BLK1 SCHME DIR REV
at one end of the line, the reverse-looking element used as
Range: Disabled, Enabled
CONTROL ELEMENTS
entries are
entries are primarily
5-393
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