For the approximate equivalent circuit of Phasor Diagram of Transformer is shown in Fig. 3.16(b)
It will be shown in Sec. 3.9 that V2 > V1 only when leading phase angle 0 is more than tan-l(R/X) (see Eq. (3.67).
In the plasor diagrams of Fig. 3.17(a) and (b) (these are not drawn to scale), the angle 6 is such that V1 leads V2. This is an indicator of the fact that real power flows from side 1 to side 2 of the transformer (this is proved in Section 8.9). This angle is quite small and is related to the value of the equivalent reactance: resistance of the transformer being negligible.