Hermetically sealed distridution transformer 1

[rzgpp]

Hi everyone!Can sameone explain is it possible to fill up sealed transformer on site?There is a drain valve on the bottom of transformer.After few procedures of oil sampling...how to prove oil level is ok?There is no oil level indicator.Can someone give me a procedure?Also there is a bad gasket on bushings..and oil leak..I want to change the gasket...and fill up the transformer.Have done this,but on conservator type transformer.

 

[waross]

You need to contact the manufacturer for their specific procedures.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[rzgpp]

There is no option to contact the manifacturer.Thank you!

 

[RRaghunath]

Sealed transformer is not meant to be maintained/repair at site.
It is 'sealed' and you are expected to replace the transformer when it fails. Send the failed transformer to the manufacturer to negotiate a discount while purchasing replacement.
Follow the instruction manual that came with the transformer with regard to periodicity of oil testing etc. Sealed transformer is supposed to minimise the maintenance / testing at site and unnecessary / frequent testing will only cause oil level in the tank to drop to the level of exposing the core/coil and lead to eventual failure of transformer.

 

[rzgpp]

Thanks for your answer RRaghunath!It is not possiible to contact manifacturer...or send to them....there is no manual....or with years it is lost!The tests are made after rain storms...but about 7 yeas...it is made 3 times.It is about 3 litres of oil,but transformer is small size...100 KVA....

 

[RRaghunath]

You are doing too much testing on a 100kVA transformer I suppose. This size and with sealed arrangement, it should be use and throw type.
One transformer manufacturer indicates the same when I googled for sealed distribution transformers:

https://www.urjatransformers.com/He...lity makes regular maintenance impracticable.

 

[waross]

You can carefully clean the port where you drew the oil for testing.
Then you can connect clean lines to the port and force some oil under pressure back into the transformer.
You can expect that there will be some dirt or contamination that was not able to be cleaned completely.
You can expect this to be carried into the transformer and contaminate the windings.
You can expect the contamination to cause a transformer failure possibly in hours, possibly in days.
You will not sleep easily waiting for the midnight call that the transformer has failed.
How does the cost of a crew for a day compare with the cost of a 100 KVA transformer?
If it is critical, change it now.
If it is not critical, it will probably last years longer if you do nothing.
It it isn't broke, don't broke it.
PS.Don't test the oil again.
Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[prc]

Since it is a sealed transformer without oil indicator, but oil leaking from cover mounted bushing you can assume that there is oil inside and no need to fill more oil. Stop oil leak using a quick setting epoxy putty .Probably that is all you need to do on that sealed unit.