Calculated Ground Trip
Description
The ground current is an imbalanced current flowing through the neutral of the three-phase system. In normal conditions, the ground current is negligible or null. It is present only when a ground trip occurs.
 DANGER |
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IMPROPER TRIP DETECTION
Failure to follow these instructions will result in death or serious injury.
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The ground current is calculated internally by the LTMTCT/LTMTCTV sensor module. The Calculated Ground Trip protection function generates the following signals:
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Alarm: Calculated ground current goes above the alarm level.
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Trip: Calculated ground current goes above the trip level for the specified time delay.
The protection function can be disabled when the motor is in Start state, to avoid nuisance tripping.
It is recommended to use the following for Calculated Ground Trip protection:
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IFLCmin= 0.3 A in 0.3-3 A (similarly for 25 A and 100 A).
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Minimum ground trip threshold = 50% of 0.3 A = 0.15 A.
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If you keep protection setting below 50% of IFLCmin, then use measured ground trip with CBCT.
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Calculated Ground Trip protection is not applicable in single-phase mode.
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Hysteresis is not applicable for calculated ground current by setting less than 10% of FLC.
Parameter Setting
The Calculated Ground Trip protection function has the following configurable settings:
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Parameter |
Setting range |
Default value |
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Function |
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Trip |
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Trip Level |
10–500% of IFLC in step of 1% |
20% of IFLC |
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Time Delay |
0.05–600.00 s in step of 0.01 s |
0.2 s |
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Alarm Level |
10–500% of IFLC in step of 1% |
20% of IFLC |
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Reset Mode |
|
DI + Reset Key |
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Auto-Reset Delay (applicable only if Reset mode is Auto) |
0–6000.0 s in step of 0.1 s |
0.0 s |
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Function While Motor Starting |
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Disable |