Why Delta Star Transformers are used for Lighting Loads?

For lighting loads, neutral conductor is must and hence the secondary must be star winding. and this lighting load is always unbalanced in all three phases. To minimize the current unbalance in the primary we use delta winding in the primary. So delta / star transformer is used for lighting loads.

Lighting loads are single phase loads and fed through a phase and the neutral wire. The neutral wire is derived from the star point of the star-delta transformer and the lighting loads are equally distributed on all the phases.

For lighting loads, neutral conductor is must and hence the secondary must be star winding. and this lighting load is
always unbalanced in all three phases. To minimize the current unbalance in the primary we use delta winding in the primary. So delta / star transformer is used for lighting loads.