Replacement cost of a transformer conservator bladder

[Beengineer]

One of our 1966 ASEA, 75MVA transformer has a damaged conservator bladder.

If you have the experience about the transformer conservator bladder replacement, could you share with me what is the ballpark cost of such replacement?

Thanks

 

[DTR2011]

It's difficult to give an exact answer, however I can tell you where the costs will be.

The bladder itself you will likely have to go to ABB for. Not a huge part of the overall cost.

The real costs will be in the labor and how you decide to execute the job. The transformer nameplate should tell you how many gallons of oil are in the conservator. You will also need to know if this is sealed or free breathing. The voltage level will also be a consideration as to how you deal with the oil you remove.

The largest costs will be labor. Where are you in the world? Are you a utility? Do you have union or non union labor? Are you considering an outside contractor for this? When do you plan on doing the work and what will the temperatures be. Oil is more difficult to move when it is cold.

How many overall gallons of oil does this XFMR have and have you also considered doing routine tests on the unit while it is out? Do you have an accurate feeling for the transformer paper moisture content, an if so, would performing an overall dryout of the unit be worthwhile add additional years to your unit?

What are the costs for lost power through the transformer? Is it a GSU?

Some repairs can be handled with containing the oil in 55 gallon barrels and a portable vacuum pump. Other repairs require larger oil treatment trucks.

I have performed such repairs in the field and would ask these questions when bidding the job.

 

[Beengineer]

THank you smallgreek.

We are the utility co in the US. We have the tank trucks that can handle large amount of oil. Yes our crew are in union. We plan to do it in the summer, which typically is around 75-80F. It's not a GSU, but a quite critical transformer. We are the winter peak, so the system can take N-1 condition in teh summer (plus the load switching), with no much problem. The moisture content is higher than normal, but is mild. It's a free breathing conservator transformer.

 

[DTR2011]

Does your crew normally handle these types of repairs? If so, why not ask them to estimate the labor (in hours).

You may also need to remove the conservator and work on the ground, for ease and safety. That would require a crane and operators. Hopefully your crew is capable of multi skills. I've worked in the Midwest and have found that some utilities are better than others at having transformer crews that know how to get the job done efficiently, while others suffer from....