GE Multilin F35, Instruction Manual

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GE Multilin F35 Multiple Feeder Protection System 5-145
5 SETTINGS 5.6 CONTROL ELEMENTS
5
c) INCIPIENT FAULT DETECTOR
PATH: SETTINGS
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CONTROL ELEMENTS
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MONITORING ELEMENTS
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INCIPIENT FAULT 1(6)
There are two incipient cable fault detection elements for each CT/VT module in the relay.
Before a permanent cable fault occurs, there are usually signs of degrading insulation manifesting itself as a short, mostly
half-cycle spikes asserting at the phase voltage peak. Due to shortness of such spikes, they are not usually detected by the
instantaneous protection of the feeder, which operates on the RMS or fundamental component of the phase current with a
relatively high pickup.
The number of detected incipient faults in each phase is counted and available in the
ACTUAL VALUES
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STATUS
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INCIPI-
ENT FAULT
menus. The counters can be reset with the
COMMANDS
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CLEAR RECORDS
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CLEAR INCIPENT FAULT COUN-
TERS
command.
Changes to any of the incipient cable fault detector settings resets of the number of the incipient faults detected to
zero.
To provide a clear timing indication when the incipient fault occurred, the incipient fault event is time-stamped with
the time the fault actually occurred. However, the FlexLogic™ operand is asserted four cycles later, when the incip-
ient fault pattern is confirmed and therefore detected.
The following figure illustrates a recorded field case of an incipient phase B fault. The top portion of the figure shows the
raw A, B and C currents. The bottom portion shows the neutral current (blue) and reveals the fault period from under the
load and the superimposed phase B current (red). The superimposed current shows two fault current blips as the data
slides through the two-cycle memory window. During the actual fault, the neutral current and the superimposed phase B
currents closely correspond, confirming the incipient fault hypothesis and identifying the affected phase.
„
INCIPIENT FAULT 1
„
INCIPIENT FAULT 1
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
INCIPNT FLT 1 BLOCK:
Off
Range: FlexLogic™ operand
MESSAGE
INCIPIENT FAULT 1
SOURCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
MESSAGE
INCIPIENT FAULT 1
PICKUP: 0.50 pu
Range: 0.10 to 10.00 pu in steps of 0.01
MESSAGE
INCIPNT FLT 1 MODE:
Number of counts
Range: Number of counts, Counts per window
MESSAGE
INCIPIENT FLT 1 TRIP
COUNTS NUMBER: 2
Range: 1 to 10 in steps of 1
MESSAGE
INCIPNT FLT 1 DETECT
WINDOW: 10.00 s
Range: 0.00 to 1000.00 s in steps of 0.01
MESSAGE
INCIPIENT FAULT 1
RESET DELAY: 0.100 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
INCIPIENT FAULT 1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
INCIPIENT FAULT 1
EVENTS: Disabled
Range: Disabled, Enabled
NOTE
NOTE