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Topic Title: Neutral Grounding Sizing for the Generator
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Created On: 06 February 2013 11:08 AM
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 06 February 2013 11:08 AM
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jackdaniel

Posts: 69
Joined: 29 November 2012

Hi Guys,

Please help me how to sizing the neutral/Grounding cable of the Generator to be connected to resistor

Edited: 07 February 2013 at 12:14 AM by jackdaniel
 09 February 2013 09:40 AM
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dlane

Posts: 690
Joined: 28 September 2007

The size of the cabling between the generator neutral point and the earthing resistor is usually set by the fault limiting capability of the resistor and the time taken for the fault to clear.

Kind regards

Donald Lane
 11 February 2013 09:09 AM
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jackdaniel

Posts: 69
Joined: 29 November 2012

How to calculate the ground fault of the transformer/generator?
 11 February 2013 02:37 PM
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dlane

Posts: 690
Joined: 28 September 2007

For onshore equipment fault levels are calculated to IEC 60909.

You will need to the fault levels of any existing feeds into the circuit and convert them to the same base. You then need to know the impedances of the apparatus again to the same base. For a generator you will also need to know its reactances.

After that it basic maths and number crunching.

Kind regards

Donald Lane
 11 February 2013 05:30 PM
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MickeyB

Posts: 181
Joined: 18 January 2003

Typically full load current of generator for low impedance earthing. 200A full load current @ sqrt 3 11000V for resistor size. R = V/I

Cable is rated at phase to earth voltage on the neutral side with regular CPC on the earth side.

High impedance earthing can be as low as 25A
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