GE F60 Instruction Manual page 369

5 SETTINGS
• INCIPIENT FAULT 1 RESET DELAY: This setting specifies a reset time for the output after the trip is initiated.
SETTING
INCIPIENT FAULT 1 FUNCTION
= Enabled
= Disabled
AND
SETTING
INCIPIENT FAULT 1 BLOCK
= OFF
SETTING
INCIPIENT FAULT 1 SOURCE
= IA
= IB
= IC
= IN
COMMAND
CLEAR INCIPIENT FAULT
COUNTERS
= Yes
Figure 5–118: INCIPIENT CABLE FAULT DETECTOR SCHEME LOGIC
g) VT FUSE FAILURE

PATH: SETTINGS CONTROL ELEMENTS
 VT FUSE FAILURE 1

Every signal source includes a fuse failure scheme.
The VT fuse failure detector can be used to raise an alarm and/or block elements that may operate incorrectly for a full or
partial loss of AC potential caused by one or more blown fuses. Some elements that might be blocked (via the
are distance, voltage restrained overcurrent, and directional current.
There are two classes of fuse failure that may occur:
• Class A: loss of one or two phases.
• Class B: loss of all three phases.
Different means of detection are required for each class. An indication of class A failures is a significant level of negative-
sequence voltage, whereas an indication of class B failures is when positive sequence current is present and there is an
insignificant amount of positive sequence voltage. These noted indications of fuse failure could also be present when faults
are present on the system, so a means of detecting faults and inhibiting fuse failure declarations during these events is pro-
vided. Once the fuse failure condition is declared, it will be sealed-in until the cause that generated it disappears.
An additional condition is introduced to inhibit a fuse failure declaration when the monitored circuit is de-energized; positive-
sequence voltage and current are both below threshold levels.
The function setting enables and disables the fuse failure feature for each source.
GE Multilin
SETTINGS
INCIPNT FLT 1 MODE
INCIPIENT FLT 1 TRIP
COUNTS NUMBER
SETTING
INCIPNT FLT 1 DETECT
WINDOW
INCIPIENT FAULT 1
PICKUP
RUN
RUN Detection logic
T
I I
– > PICKUP
´
mag mag
I
where is 2 cycles old
mag ´

MONITORING ELEMENTS
VT FUSE FAILURE 1
FUNCTION: Disabled
F60 Feeder Protection System
SETTINGS
INCIPIENT FAULT 1
RESET DELAY
0
T
RST
0
WINDOW T
RST
0
T
RST

VT FUSE FAILURE 1(4)
Range: Disabled, Enabled
5.7 CONTROL ELEMENTS
FLEXLOGIC OPERANDS
INCIPNT FLT 1 OP A
INCIPNT FLT 1 OP B
INCIPNT FLT 1 OP C
INCIPNT FLT 1 OP
OR
FLEXLOGIC OPERANDS
INCIPNT FLT 1 PKP A
INCIPNT FLT 1 PKP B
INCIPNT FLT 1 PKP C
INCIPNT FLT 1 PKP
OR
ACTUAL VALUES
INCIPIENT FAULT 1 PH A
FAULTS
INCIPIENT FAULT 1 PH B
FAULTS
INCIPIENT FAULT 1 PH C
FAULTS
RESET
832028A1.CDR
input)
BLOCK
5-229
5