GE UR F35 Series Instruction Manual page 328

5.7 CONTROL ELEMENTS
d) INCIPIENT FAULT DETECTOR
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PATH: SETTINGS CONTROL ELEMENTS
 INCIPIENT FAULT 1
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5
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
menus. The counters can be reset with the
ENT FAULT
command.
TERS
Changes to any of the incipient cable fault detector settings resets of the number of the incipient faults detected to
zero.
NOTE
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 incipient
fault pattern is confirmed and therefore detected.
NOTE
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.
5-200
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MONITORING ELEMENTS
INCIPIENT FAULT 1
FUNCTION: Disabled
INCIPNT FLT 1 BLOCK:
MESSAGE
Off
INCIPIENT FAULT 1
MESSAGE
SOURCE: SRC 1
INCIPIENT FAULT 1
MESSAGE
PICKUP: 0.50 pu
INCIPNT FLT 1 MODE:
MESSAGE
Number of counts
INCIPIENT FLT 1 TRIP
MESSAGE
COUNTS NUMBER: 2
INCIPNT FLT 1 DETECT
MESSAGE
WINDOW: 10.00 s
INCIPIENT FAULT 1
MESSAGE
RESET DELAY: 0.100 s
INCIPIENT FAULT 1
MESSAGE
TARGET: Self-reset
INCIPIENT FAULT 1
MESSAGE
EVENTS: Disabled
F35 Multiple Feeder Protection System
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INCIPIENT FAULT 1(6)
Range: Disabled, Enabled
Range: FlexLogic operand
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: 0.10 to 10.00 pu in steps of 0.01
Range: Number of counts, Counts per window
Range: 1 to 10 in steps of 1
Range: 0.00 to 1000.00 s in steps of 0.01
Range: 0.000 to 65.535 s in steps of 0.001
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
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COMMANDS CLEAR RECORDS
5 SETTINGS
 
ACTUAL VALUES STATUS
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CLEAR INCIPENT FAULT COUN-
GE Multilin
INCIPI-