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Participant

Join Date: Apr 2014
Posts: 3

Tranformer Oil DGA & Furan

04/19/2014 8:57 AM

Is there any method to find out the furanic value with the help of DGA results & the transformer working temperature? Please advice.

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Guru

Join Date: Jul 2007
Location: Commissariat de Police, Nouvions, occupied France, 1942.
Posts: 2599
Good Answers: 77
#1

Re: Tranformer oil DGA & Furan

04/19/2014 9:39 AM

Did you telephone the transformer manufacturer, Agnes?

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Participant

Join Date: Apr 2014
Posts: 3
#2
In reply to #1

Re: Tranformer oil DGA & Furan

04/19/2014 9:57 AM

I did, but they don't have an equvation. Is there any general methods for that?

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Guru

Join Date: Oct 2008
Posts: 42377
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#3
In reply to #2

Re: Tranformer oil DGA & Furan

04/19/2014 11:13 AM
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Power-User

Join Date: Jul 2013
Location: Faridabad Near New Delhi India
Posts: 240
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#4

Re: Tranformer Oil DGA & Furan

04/20/2014 1:23 AM

Sreekumar while I always admire and encourage new thinking which brings in innovations, but as far Dissolved Gas Analysis is concerned it is a diagnostic tool than knowing operating temperature of oil under normal operation.

For example if hot spots are developing inside transformer DGA will diagnose same. For knowing normal operating temperature of transformer oil Temperature Gauge and Transmitter are better tools.

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Commentator

Join Date: Sep 2011
Location: Durban South Africa
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#5

Re: Tranformer Oil DGA & Furan

04/20/2014 2:08 AM

DGA; dissolved gas analysis measures dissolved gas and working temperature measures temperature. Farane test measures the amount of paper (ie insulation) in the oil. There is no equation for the relationship. Eventually the windings will lose enough paper to cause hot spots which will increase the dissolved gas and the oil temperature and the whole thing will blow up but there is no formula for this. (Why does everything have to have a formula?)

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Power-User

Join Date: Jan 2007
Location: Johannesburg, South Africa
Posts: 212
Good Answers: 14
#6
In reply to #5

Re: Tranformer Oil DGA & Furan

04/21/2014 1:12 AM

As beentheredonethat stated, DGA measures dissolved GAS. Furanic analysis measures paper dissolved in the oil, which is not a gas. The two are not related, as DGA gives you only some indications of insulation failure. Apart from hot-spots, DGA will also give warning of internal arcing (I've twice had cases where there was warning if internal arcing picked up by DGA, both times due to tap-changers that had their tap settings changed after years of being in the same position). Furanic analysis is an indirect measurement of paper insulation condition, but still worthwhile on older transformers. The other alternative is a direct sample of the paper, but for that the transformer has to be opened up, so it is a rather invasive procedure.

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Commentator

Join Date: Sep 2011
Location: Durban South Africa
Posts: 75
Good Answers: 2
#7
In reply to #6

Re: Tranformer Oil DGA & Furan

04/21/2014 1:52 AM

Gideon

You're quite right. That is why it is advisable to have on line tap changers on a separate oil system (tank and conservator).

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beentheredonethat (2); Crabtree (1); gideon (1); lyn (1); powersolutionsFBD (1); Sreekumar (1)

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