I have a confusion about phase shift in a transformer.
When there is a delta/star or star/delta transformer is there,
we say that 30degree phase shift occurs.
What does it mean physically?
yes there is a 30 degrees phase shift in a delta/star or star/delta transformer.the reason is that the phase voltage lags line current by 30degrees.for your understanding consider a delta/star transformer.consider the phase voltages in three phases of both primary and secondaries.you will find that in primary the phase voltage and line voltages are same,let it be Vab(take one phase).but,the corresponding secondary will have the phase voltage only in it's phase winding as it is star connected.the line voltage of star connected secondary and delta connected primary won't have any phase differences between them.so this can be summerised that”the phase shift is associated with the wave forms of the three phase windings.for clear idea refer the phasor diagrams of star and delta connections simultaneously.