184 D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED PROTECTION ELEMENTS CHAPTER 7: PROTECTION
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
automatic reclosure is employed. Co-ordination is achieved by all of the line pickup
undervoltage elements resetting and blocking the trip path before the autoreclose co-
ordination delay 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 LINE PICKUP RCL TRIP FlexLogic operand. For security, the overcurrent trip is supervised
by an undervoltage condition, which in turn is controlled by the VT FUSE FAIL OP operand
with a 10 ms coordination timer. Configure the LINE PICKUP RCL TRIP operand to perform a
trip action if the intent is zone 1 extension.
The zone 1 extension philosophy used here normally operates from an under-reaching
zone, and it uses an overreaching distance zone when reclosing the line with the other line
end open. The
Autoreclose Accelerate setting is provided to achieve zone 1 extension
functionality if external autoreclosure is employed. Another zone 1 extension approach is
to apply permanently an overreaching zone, and reduce the reach when reclosing. This
philosophy can be programmed via the autoreclose scheme.
Select the Settings > Protection > Elements > Group 1 > Line Pickup menu to open the
line pickup configuration window. There is one line pickup element for each setting group.
Figure 163: Line pickup configuration window
The following settings are available.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the line pickup feature.
Signal Source
Range: LINE (SRC 1), BKR 1 (SRC 2), BKR 2 (SRC 3)
Default: LINE (SRC 1)
This setting selects the signal source for line pickup protection.
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