Earthing of neutral on single phase transformer

[nbys]

HI All
I cannot understand the physics of why a neutral that is ungrounded will be at a higher voltage relative to a live on a single phase transformer lets say a 11kV to 230 V trf . not centre tapped as opposed to when the neutral is grounded
i need to see some diagrams and calcalutions from 1st principles please
it is troubling me
regards

 

[wcaseyharman]

Well, if the 230V side has no ground reference then presumably the neutral voltage could be anywhere depending on the leakage impedance to ground. I’ve seen similar issues with ungrounded DC systems - typically they float with positive and negative sides equal between ground unless one side has a different ground resistance, like a junction box getting wet.
A 230V system should act similarly - the neutral would be close to ground potential unless the impedances to ground on either leg were different - granted, I haven’t come across an ungrounded 230V single phase system so don’t have direct experience. Several 480V 3 phase systems though.