Transformer failed

If you expect an answer, give us a LOT more detail! (Voltages, currents, kind of devices being connected, kind of network, switching devices, etc.)

Please supply a crystal Ball so that we may fully understand what you are asking,, otherwise full pertinent information.

It is better in such cases as to supply too much info, rather than too little!! You have not supplied too little, basically you have supplied nothing!!

OK, this is conjecture. It sounds like there was too much current in the transformer. Either the transformer was too small for the load or there was a short circuit in the load and there was no fuse to protect the transformer. Or the load was too large and the heat degraded the transformer insulation until it shorted out the winding. Like I said, this is speculation. As Andy said, until there is more information there's not much else to say.

Heat caused by something.

my friend , it would be better 4 u to supply more specific data ( like Transformer KVA,Cables connected sizes,Wheather temperature , Load connected to low voltage side , Way of connection.........etc.)

but for the meantime it seems to me that if the transformer was running for a period of time , the wrong connection option will be neglegted , may be the size or capacity of transformer is lower the one needed for the load.

I'm leaving this blog as you seem unable for some reason to give any needed, detail......

I assume that that sanad may not be an electrical professional and his command of the english language may not make it possible for him to provide the missing details , hence the reason for the omission of of significant details.

So instead of knocking him flat, I would like to suggest a few reasons whay the LV winding in a transformer may burn ;

transformers in storage where higher than normal moisture levels may have invaded the transformer.

The LV winding may have overloaded and there was not adequate protection to isolate the transformer.

The LV winding may have been incorrectly connected.

Any of the above combinations.

I assumed the HV side is primary.

WHAT?????????????

Are we talking about a transformer to power your electric razor, or a transformerr to power half of Slogovia?? After researching your previous entries (I should not have to do this) you use the term "distribution transformer". I assume then that you are talking a BIG transformer and not a toy.

Regret, for late participation, however I found it an interesting topic despite of the lack of essential information required to provide you with a conclusion somehow close to the reason behind the failure of your transformer.

In addition to all above queries, you have to clarify the following:

Why the transformer was originally shut down?

OR WHETHER
It was a new transformer and you trying to put it into service?

It was an existing one and manually tripped to carry out some routine maintenance?

It was an existing one and tripped through the protection system due to a fault? What was the type of fault (internal or external)?