The voltage control is performed by changing the turns ratio. This is done by provi-
sion of taps in the winding. The volts per turn available in large transformers is quite high
and hence a change of even one turn on the LV side represents a large percentage change
in the voltage. Also the LV currents are normally too large to take out the tapping from
the windings. LV winding being the inner winding in a core type transformer adds to the