What is the reason?

April 25, 2020   photos  

Buckling of the tank is caused by tank over pressure. Pressure relief valve failure . Buckshot relay should read that also.In addition to this, transformer tank bulging out towards explosion. This is caused by violent faults within the transformer whose protection has taken longer or failed to operate. The is more production of heat From the winding due to insulation failure resulting into the boiling of oil thus producing pressure withing the TX. The transformer oil heating at high temperature producing dissolved gases inside the transformer creating high pressure inside pushing out the transformer structure.