Transformer Life

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steve66

steve66

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Location
Illinois
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Engineer
I have a client that would like a plan to replace a transformer before it becomes too likely that it dies a sudden death.

I assume that the older a transformer gets, the higher the probablitiy that a failure will happen. And I can understand wanting to replace the transformer before the probably gets too high. But I have no idea how to put this into a calculation. Can anyone suggest a source, or have any ideas.

My gut feeling is that since it is a new transformer, they probably don't have to worry about replacing it until after I retire:)

Steve
 
IEEE 57.91 is a good starting point. Although it is based on oil-filled technology, most of the "design life" points are similar across the board for power transformers. It is a LONG document.

Unless the transformer is abused in some manner, your "gut feeling" is highly likely.
 
transformers

transformers

kingpb said:
Without abusive behavior, a transformer could ,and do, last 50 years.
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not scientific, but, for my part, I agree. I've been involved in electrical for around 50 years and most of the transformers I've met are doing better than I am. :grin:
 
It's a 150KVA dry type transformer. It will share a room with a UPS, so there will be nice cool air conditioning for the transformer.

It will feed computer racks in a data center. As a result, I also plan to make it a K rated transformer.

Square D lists K-4 and K-13 transformers. I figured the K-13 is called for, since the entire load will basically be non-linear loads. Does that sound reasonable? Or does a K-13 sound like overkill?

Steve
 
Switching loads put a beating on a transformer due to increased core losses from the harmonics. A K rated transformer will help, but it wont last 50 years. Your best bet is to have the unit tested at least every few years, DAR, IR, TTR vaules will help predict a faileure before it occurs.
 
steve66 said:
It's a 150KVA dry type transformer. It will share a room with a UPS, so there will be nice cool air conditioning for the transformer.

It will feed computer racks in a data center. As a result, I also plan to make it a K rated transformer.

Square D lists K-4 and K-13 transformers. I figured the K-13 is called for, since the entire load will basically be non-linear loads. Does that sound reasonable? Or does a K-13 sound like overkill?

Steve
Click to expand...

The UPS will die long before he has to worry about the transformer. If it doesn't die a 50 year old electronic technology would be unserviceable. Capacitors die at about 10 years.
 
weressl said:
The UPS will die long before he has to worry about the transformer. If it doesn't die a 50 year old electronic technology would be unserviceable. Capacitors die at about 10 years.
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True, bthe UPS probably won't last as long, but at least the UPS can bypass itself when it does die. And we are using a flywheel instead of batteries.

Steve
 
steve66 said:
True, bthe UPS probably won't last as long, but at least the UPS can bypass itself when it does die. And we are using a flywheel instead of batteries.

Steve
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Your original question was not addressing failure rate, only design life.

There are also no guarantee to failure mode on the UPS. It could loose the critical load tomorrow. No UPS manufacturer will give you a guarantee on power loss and consequentual losses.
 
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