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Power-User

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Transient Over Voltage

10/05/2012 2:01 AM

In neutral grounded power system transient over voltage is controlled by neutral grounding.Let us consider for Delta connected system how the transient over voltage will be controlled because there is no neutral point and neutral grounding too.

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#1

Re: Transient over voltage.

10/05/2012 2:57 AM

"Neutral" and/or grounding has nothing to with voltage transients.

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Power-User

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#4
In reply to #1

Re: Transient over voltage.

10/05/2012 5:45 AM

then what is the purpose of neutral grounding?

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#5
In reply to #4

Re: Transient over voltage.

10/05/2012 6:01 AM

To provide a path for the fault current until the circuit protective device(s) disconnect(s) the fault.

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#6
In reply to #4

Re: Transient over voltage.

10/05/2012 2:33 PM

Safety. When any metal part which is grounded, reach a high voltage due to fault condition, a large current will flow through ground to neutral and this will blow the fuse or open a breaker.

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#7
In reply to #6

Re: Transient over voltage.

10/06/2012 10:22 AM

Maybe you were in a hurry, because what you described is frequently not the case. It sounds as if you are expecting a current interrupting device to be present in the neutral line and I know that is not what you meant. Care to clarify?

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#2

Re: Transient over voltage.

10/05/2012 3:14 AM

Which source of transient are you referring to ?

If it is switchgear operation, neutral has little to do .

If it is external lignhning, things are different.

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#3

Re: Transient over voltage.

10/05/2012 3:43 AM

If there is no neutral, and no grounding point, and therefore no reference point, of what consequence is transient over-voltage <rhetorical question - NNTR>?

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Guru

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#8

Re: Transient Over Voltage

10/06/2012 11:29 AM

It is such a long discussion. Can you mail me your e-mail ID thro this forum's mailbox so that I can send you a deatiled reply?

And.. for the time being, whether it is delta connected or star connected, there would be huge transient over-voltages in the ungrounded/impedance grounded system due to resonance between ground leakage capacitance and system inductance

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Power-User

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#10
In reply to #8

Re: Transient Over Voltage

10/08/2012 8:22 AM

my mail id is CR4 Admin - email address removed

From the CR4 Rules: Do not post phone numbers or email addresses. The CR4 Admin will delete all phone numbers and email addresses posted in threads or comments. You can share this information via the CR4 internal messaging system.

kindly mail me.

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Guru

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#11
In reply to #10

Re: Transient Over Voltage

10/08/2012 9:28 AM

I said thro this forum's mail box

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Active Contributor

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#9

Re: Transient Over Voltage

10/06/2012 12:27 PM

Neutral grounding in three phase systems is NOT for the control of transient voltages.

In delta connected systems, paths for zero sequence currents can be achieved by the use of EARTHING TRANSFORMERS.

Regards

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