Effect of connecting transformer neutral and body earthing

Not sure what you mean by 'body earthing' here.  In a normal TT system the neutral is earthed at the substation, and the core of the transformer may share that LV earht or may have its own 'HV earth' - mainly that decision comes down to the likely voltage rise during fault.

Mike.

If however you mean earthing the neutral at another transformer fed by the substation, that is some TNC varient. I suspect not what you meant.

If however you mean earthing the neutral at another transformer fed by the substation, that is some TNC varient. I suspect not what you meant.