Grouped Protection Elements; Line Pickup - GE D90 Plus Instruction Manual

GROUPED PROTECTION ELEMENTS

Grouped protection elements

Line pickup

182
Each protection element can be assigned up to six different sets of settings according to
setting group designations 1 to 6. The performance of these elements is defined by the
active setting group at a given time. Multiple setting groups allow the user to conveniently
change protection settings for different operating situations (for example, altered power
system configuration or season of the year). The active setting group can be preset or
selected via the Settings > Protection > Control > Setting Groups menu item.
The line pickup feature uses a combination of undercurrent and undervoltage to identify a
line that has been de-energized (line end open). Alternately, the user may assign a
FlexLogic™ operand that specifies the terminal status. Three instantaneous overcurrent
elements are used to identify a previously de-energized line that has been closed onto a
fault. Faults other than close-in faults can be identified satisfactorily with the distance
elements.
Co-ordination features are included to ensure satisfactory operation when high-speed
autoreclosure is employed. Co-ordination is achieved by the line pickup undervoltage
elements resetting and blocking the trip path before the autoreclose co-ordination times
out.
The line pickup protection incorporates zone 1 extension capability. When the line is being
re-energized from the local terminal, pickup of an overreaching zone 2 or excessive phase
current within eight power cycles after the autorecloser issues a close command results in
the FlexLogic™ operand. For security, the overcurrent trip is supervised
LINE PICKUP RCL TRIP
Figure 161: Example use of sources
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION