Hi, can anyone tell us about magnetic circuit of three phase transformer?

Three Phase Transformer Phase Angle and Magnitude Distortion due to Unsymmetrical Core Reluctance Seen by Each Phase

In 3 leg three phase transformer, do we get some phase voltage manitude and angle change due to un-symmetrical reluctance seen by every different phases? The phase at the middle leg is not distorted because fluxes come from both rear legs equally in magnitude. But voltage and angle of rear legs change somewhat because the other two phases' flux come to rear legs in different magnitudes. So this distorts both magnitude and angle of voltage.

Is there a such thing? And how much is this effective?

The manufacturer of the transformer should provide a hysteresis curve of the transformer magnetic characteristics with its technical data. The magnetic and electrical flux contribute to the internal impedances of the transformer core and its windings.