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pkmassar
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Join Date: Mar 2008
Posts: 2

Tripping of Relay

11/04/2011 11:20 AM

How to overcome the nuisance tripping of relays for protection of 33KV/11KV, 7.5MVA transformer during synchronisation of 2000HP auto synchronous induction motor?
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Pathfinder Tags: auto synchronous induction motor tripping relay
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redfred
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Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
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#1

Re: Tripping of relay

11/04/2011 11:29 AM

You should first ask yourself this question. Which is the bigger nuisance, resetting a protection relay or blowing up what the relay tried to protect?

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TonyS
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United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
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#2

Re: Tripping of Relay

11/04/2011 5:55 PM

What indication is the relay giving when it trips.

You should be looking for a "real" fault, not trying to mask it by changes to the relay settings. I hope the system was set up by an engineer of some repute.

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Anonymous Poster #1
#3

Re: Tripping of Relay

11/05/2011 1:28 AM

2000HP = almost 1500KW =1.5MW which may be about 1800MVA at input (electrical)

The starting current in case yiou are DOL starter may be about 5-6 times minimum and that corresponds to the current of 9MVA (though I don't expect that you might be doing such a large motor on DOL)
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electricalexpert65
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Join Date: Oct 2009
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#4

Re: Tripping of Relay

11/06/2011 9:02 AM

If you feel tripping is nuisance, why have a relay at all? Throw out the relay and... start stocking enough transformers.
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