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

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bdn2004

bdn2004

Electrical
Jan 27, 2007
799
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?
 
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Several manufacturers: Hydran is one. There are several others that my ADD mind won't let me remember right now. Try an internet search for transformer oil analyzers.
 
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A few others I have used:

Morgan Schaffer - Calisto
Serveron (I wish I could remember the model)

You can even get the information online in real time from a remote location. Dynamic Ratings comes to mind, but I'm sure there are other companies that do this.

Be mindful that most units simply monitor Hydrogen (and oftwen moisture) and they DO NOT REPLACE YOUR ANNUAL DGA! There are several more advanced units that will monitor things like methane and acetylene. I still would not consider these as a substiute for an annual DGA. However the oil monitors can give you an early warning in case something is wrong with one of your transformers.

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

What is a carrier gas? And why is that better?

 
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Bdn, the carrier gas is an inert gas such as helium used to transport the dissolved gases to the instrument. The downside is the maintenance liability, storage of replacement cylinders etc. That's why personally I favour the units that do not have any consumables.
Regards
Marmite
 
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Do be aware that the expected lifetime of any of these units is significantly less that of the transformer they are mounted on. Although some units are advertised as having no "consumables" they may still require service & replacement parts on a 3-4 year cycle.

Purchasing a 10 year service contract for one of the monitors was quoted at 1.8 times the cost for the unit. The extra $4000 per year per monitor in O&M costs makes it hard to justify on all but our biggest transformers.
 
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DGA on-line monitors are available with different levels of sophistication.Uppper band units have a separtae cubicle fitted to transformer sampling valves,with an integral oil pump to circulate oil and take sample ,say morning and evening, do DGA of all important gases and report results to an office 1000km away,all automatically.
Apart from Kelman some other sources.
1) 2) 3) The last ones are from Korea and China.
 
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ABB make (used to make?) an online monitor. I think they were developing it with GE Syprotec. Perhaps another avenue to explore. Memory suggests it was called "T-Monitor" or something similar.


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T-Monitor was a comprehensive transformer on-line monitoring system.gases,temperature,moisture ,V,I etc.ABB also have an on-line DGA system.Kelman was taken over by GE Energy.
 
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Thanks prc. We looked at that system many years ago for a generator transformer with a hot fault somewhere we couldn't identify in spite of several internal inspections.


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I did get info from GE. Theirs monitors for 8 different gasses...And it can be ours, without installation costs for around $40,000. By the time its installed it will cost $100K. I'm anticipating a tough sell.
 
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$40k and 100K installed! Wow! Now that's one expensive unit! All you need is power and a set of alarm contacts! Just a few years ago I was quoted $25K for an oil monitor for a critical GSU transformer. We put a $9k unit on it. It did Hydrogen and moisture only. Last year it detected higher levels of hydrogen that had trended up for a few months so we took a DGA and found Acetylene so we took the unit offline a few weeks later.

In my experience, the units that detect Hydrogen only do a fair job of detecting a fault in time. But like I said earlier, this doesn't replace the need for a DGA annually or even biannually. You can go straight to Acetylene without seeing much Hydrogen in some cases.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.
 
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We're going to want this info online and available in the Control Room so its a little more than contacts and power.

Most of the time you can count on doubling the price of anything for install. Unions do cost, and in my opinion in in the trades anyway add a layer of required safety that is sometimes seems high but shows its value by not getting anyone hurt....

9K, I mean 18K is much more reasonable.
 
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Why is the info needed inside the control room? Can't an operator go out and check it when an alarm is noticed? My experience with operators is their first instinct is to ignore their indications anyway. The real purpose of the oil monitors is not to determine what type of problem you have, but indicate that you may have an issue and should take an oil sample. That's it. Some plant engineers at the power plants would occasionally go outside and download the trend data from the monitors every once in a while, but for the most part it did little but give them peace of mind.

Out units were $9,000 to buy and cost about $4-5K to install. We had the manufacturer connect them and set them up. We had our union workers install the boxes and fittings on the transformers.

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

I thought the idea behind the gas in oil analysis is to see the trended data over a long period of time. The same thing for all the predictive maintenance gadgets we hope to install on the critical transformers. It's not just an alarming system at the transformer - that is the scenario we are hoping to eliminate.

In other words, the primary audience for this monitor will be the plant engineers and maintenance planners, not the operators. At least that is how I am conceptualizing this. If you have these installed at your plant...how do you use them?
 
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Yes, the monitor trend data is the most useful thing about the devices. It can show how rapid a fault is developing to give you some idea of your time frame before you must take your unit out of service. Mind you that your DGA trend data does the exact same thing and monitors more indicating gasses. The DGA is your true accurate monitor.

However, the online monitors usually store a year's worth of data in each unit. Most units can be set up to alarm on absolute levels and trend data. Thus, if you set your alarm levels properly, you can simply download the historic data in the event of an alarm. The only thing on line monitoring does is eliminate somebody having to go outside and hook a laptop up to it.

The oil monitors real purpose is to tell you that it is time to take a DGA and determine if further investigation is necessary. At this point when you see an alarm, you take an oil sample and download a year's worth of trend data and use it in your analysis. The oil monitors are really an early warning system more than anything. It tells you that you COULD have a problem and you SHOULD investigate it.

I'm not telling you what you are planning to accomplish is incorrect. On line monitoring is a nice feature. However what I am saying is this level of installation might be unnecessary. Remember that this was introduced to you by a salesman who's job is to tell you all the wonderful things the device can do. This doesn't mean all of it should be used for every purpose.

What I'm suggesting is coming strictly from my experience first as an end user and now as a transformer manufacturer. If you can add on line real time monitoring inexpensively, by all means do it. But if it is going to increase the cost of the installation 3 fold, it may not be worth it. Just food for thought.

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

Thanks for the insight on how you actually use these.

I'm also gathering data into the world of computers servers...where I'm no expert either. But I was thinking the data from these monitors was to be stored on the server not on the device itself.

As another option I was hoping as they do with the relays that protect the transformers, see about locating the monitors inside the Control Room itself. The Control Room is between 100'-1000' away depending upon which transformer we're talking about.
 
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