BS IEC 60076-15:2015

What is BS IEC 60076-15 – Power transformers about?  

BS IEC 60076-15 is an international standard that discusses gas-filled power transformers. Gas-filled power transformers is a transformers of which the magnetic circuit and windings are placed in an enclosure filled with an insulating gas.  
BS IEC 60076-15 applies to three-phase and single-phase gas-filled power transformers with the exception of certain categories of small and special transformers such as:  

Single-phase transformers with rated power less than 1 kVA and three-phase transformers less than 5 kVA