GE G30 Instruction Manual page 381

5 SETTINGS
• CT FAIL 1 3V0 INPUT: This setting selects the voltage source.
• CT FAIL 1 3V0 INPUT PICKUP: This setting specifies the pickup value for the 3V_0 source.
• CT FAIL 1 PICKUP DELAY: This setting specifies the pickup delay of the CT failure element.
c) VT FUSE FAILURE
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PATH: SETTINGS CONTROL ELEMENTS
 VT FUSE FAILURE 1

MESSAGE
MESSAGE
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 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. Also rapid decrease in the phase voltages magnitude from a healthy
voltage level without disturbance in current can indicate a VT fuse fail conditions. These noted indications of fuse failure
can also be present when faults are present on the system, so a means of detecting faults and inhibiting fuse failure decla-
rations during these events is provided.
GE Multilin
Figure 5–113: CT FAILURE DETECTOR SCHEME LOGIC
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MONITORING ELEMENTS
VT FUSE FAILURE 1
FUNCTION: Disabled
 NEUTRAL WIRE OPEN 1
 DETECTION: Disabled
 NEUTRAL WIRE OPEN 1
 3 HARM PKP: 0.100
G30 Generator Protection System
5.7 CONTROL ELEMENTS

VT FUSE FAILURE 1(4)
Range: Disabled, Enabled
Range: Disabled, Enabled
Range: 0.000 to 3.000 pu in steps of 0.001
5
input)
BLOCK
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