GE L90 Instruction Manual page 389

CHAPTER 5: SETTINGS
The line pickup feature uses a combination of undercurrent and undervoltage to identify a line that has been de-energized
(line end open). Alternately assign a FlexLogic operand to the
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 automatic reclosure (AR) is
employed. The
AR CO-ORD DELAY
reclose. Co-ordination is achieved by all of the
times out. The
CO-ORD DELAY
implemented.
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
supervised by an undervoltage condition, which in turn is controlled by the
coordination timer. If a trip from distance is not required, then it can be disabled with the
Configure the
LINE PICKUP RCL TRIP
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
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.
— This setting enables and disables the line pickup feature.
LINE PICKUP FUNCTION
— Selects the signal source for line pickup protection.
LINE PICKUP SIGNAL SOURCE
— Specifies the level of line current required to declare a line pickup operation when the line is re-
PHASE IOC LINE PICKUP
energized.
— Specifies the time during which the line is de-energized before the line pickup logic is
LINE END OPEN PICKUP DELAY
armed.
— Specifies the time during which the line pickup logic remains armed once the line has been
LINE END OPEN RESET DELAY
re-energized.
— The coordination timer allows the overcurrent detector to be set below the expected load current
AR CO-ORD BYPASS
seen after reclose. When this setting is enabled (the default value), the coordination timer is bypassed. Disable this setting
(removing the bypass and inserting the timer) if high speed autoreclosure is employed.
— If the setting of the overcurrent detector is less than the load current, then it picks up during a
AR CO-ORD PICKUP DELAY
normal re-energization of the line. This setting delays the assertion of the
the line voltage to block the scheme.
— This setting extends the assertion of the line pickup output when autoreclose coordination is not
AR CO-ORD RESET DELAY
bypassed.
— This setting allows the line pickup element to be armed from a status signal (such as breaker position)
TERMINAL OPEN
rather than from current and voltage. The FlexLogic operand assigned to this setting indicates that the terminal is opened.
It can be derived by combining the status of several devices in a FlexLogic equation.
— This setting provides zone 1 extension functionality if external autoreclosure is employed.
AR ACCELERATE
— Assertion of the FlexLogic operand assigned to this setting blocks operation of the line pickup
LINE PICKUP BLOCK
element.
— This setting enables and disables the logging of line pickup events in the sequence of events
LINE PICKUP EVENTS
recorder.
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
setting allows the overcurrent setting to be below the expected load current seen after
LINE PICKP UV
setting is normally enabled. It is disabled if high speed autoreclosure is
AR CO-ORD BYPASS
FlexLogic operand. For security, the overcurrent trip is
LINE PICKUP RCL TRIP
operand to perform a trip action if the intent is zone 1 extension.
setting that specifies the terminal status.
TERMINAL OPEN
elements resetting and blocking the trip path before the
VT FUSE FAIL OP
LINE PICKUP DISTANCE TRIP
setting is provided to achieve zone
AR ACCELERATE
operand, allowing the recovery of
LINE PICKUP OP
GROUPED ELEMENTS
AR
operand with a 10 ms
setting.
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