Transformer gas in oil analysis monitor/live data is this available? 3

[bdn2004]

A salesman was telling me that the latest is a meter installed at a large oil filled transformer that will continually monitor for gasses in the oil. He said Qualitrol makes it. I called. They don't.

Has anyone ever heard of or have experience with such a thing?

 

[prc]

One model of high end on-line monitors( the type I mentioned) was checked at site.The gas analysis given by this was counterchecked with lab analysis results.They were matching.But the cost of these complete gas analysers with remote monitoring facilty was prohibitive,and may justify only incase of large critical trfs like huge HV DC trfs ( each costing 5-10 MUSD) In other cases effective way may be simple manual monitoring hydrogen monitors ( like hydran )which can be monitored daily.In case of any abnormality, oil samples may be checked in lab at frequent intervals to assses the health and to take countermeasures.

 

[TurbineGen]

The Hydran is a good unit. It's fairly inexpensive and easy to install. It's accuracy isn't great, though. But it's close enough for a base loaded transformer.

My preference is the Morgan Schaffer Calisto 2. It takes a 3 hour time average of the gasses in the oil and also heat it up to a consistent temperature so the readings are more accurate. It's a bit more expensive and takes a bit more work to install (you need 2 free oil valves on your transformer), but it is easy to use and quite accurate.

The devices aren't instantaneous. In fact, checking them once a week is plenty. Just put an item on your operator's check list to write down the values on the unit. The nice thing about the Calisto is you can move it several feet away from the transformer so it can be accessed without getting inside the transformer cage (if there is one).

prc hit the exact point I was making. If you see an alarm on your oil monitor, you can take frequent oil samples which are very accurate and cost very little. Now that you have a $100k estimate from the first vendor, you can look like a savvy engineer by having two installed for less than that and achieve the same goal by adding a little procedure.

If you can give me some historic DGA results, I can help you with where to set your alarms.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.

 

[bdn2004]

Earlier today I met with the honchos and thanks to this forum I did have something to show. The Hydran unit was discounted because it appears at first glance to be moisture based, and apparently that is not the only problems they've experienced and would want something a little more robust.

And I was told that all of the transformers are as important as just the main ones. So the question was asked if one monitor could be used for multiple transformers? At some point I realize these are questions for vendors...

 

[TurbineGen]

One transformer - one monitor. Otherwise you won't have the trend data. I would recommend looking into sme of the other monitors. I have used the Calisto and found it works well.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.

 

[prc]

bdn20004 Hydran and similar vintage instruments are not for moisture alone,it is mainly for detection of hydrogen the main fault gas in any major incipient fault.Yes if you want a portable gas analyser that is also available,using which you can check hydrogen content in other units also. Then the question of man hours for sampling and testing comes in to play.The argument all transformers are equally critical may be OK. But if the cost of monitoring equipment comes half the transformer price,investment justification will be difficult.Bosses may say, buy a spare transformer instead.