Solution:

• The voltage regulation of the transformer is the percentage change in the output voltage from no-load to full-load.
• Since power factor is a determining factor in the secondary voltage, power factor influences voltage regulation. This means the voltage regulation of a transformer is a dynamic, load-dependent number.
• When the load is leading, the output voltage can be greater than the no-load value. So at leading power factors the regulation may get negative as well as positive.
• But from unity power factor to lagging power factors the output voltage will be always lesser than no-load value and hence the regulation will become positive.