Correct Answer - Option 4 : It has larger number of turns, has to handle low currents and is also easily accessible physically
Tap changing in Transformer:
It is a normal fact that the increase in lead to a decrease in the supply voltage. Hence voltage supplied by the transformer to the load must be maintained within the prescribed limits. This can be done by changing the transformer turns ratio.
The taps are leads or connections provided at various points on the winding. The turns ratio differs from one tap to another and hence different voltages can be obtained at each tap.
Need for system voltage control:
- Adjusting the terminal voltage of consumer within the prescribed limits
- Adjustment of voltage based on the change in load
- To control real and reactive power
- For varying the secondary voltage based on the requirement.
Taps are provided at the HV windings of the transformer because of the following reasons:
- The number of turns on high voltage winding is large and hence a fine voltage variation can be obtained.
- The current on low voltage winding of large transformer is high, therefore interruption of high current is a difficult taste.
- L.V winding is placed nearer to the core and H.V winding is placed outside. Therefore, providing taps on H.V winding is comparatively easier than that of the L.V winding.
