Since this is a DIY site, it might show consideration to others if those who "know things" could give a supplementary reference (e.g. See xyz) or a little bit of explanation to their (no doubt) quite erudite comments.
I have ascertained that "Dyn11" is a reference to an IEC designation, which indicates a (HV to lv) Delta/star transformer, with an Earthed Neutral on the secondary).
However, I do not see why/how this indicates that "the phase angle of the LV winding lags the HV by 330 degrees, which can also be said that LV windings leads the HV by 30 degrees", as contained in the reference which I located.
It must be in those additional "11" numerals, but why?
If possible, please explain!