A power factor less than unity results in which of the following disadvantages?(i) Large kVA rating of equipment(ii)Poor voltage regulation(iii) Greater conductor size

• A. (ii) and (iii) only
• B. (i) and (iii) only
• C. (i) and (ii) only
• D. (i), (ii) and (iii)

Answer: (D)

The load current is inversely proportional to the power factor, if power is constant
Lower the power factor, higher is the load current.
kVA rating of the equipment is inversely proportional to power factor.
The smaller the power factor, the larger is the kVA rating.
Therefore, at low power factor, the kVA rating of the equipment has to be made more, making the equipment larger and expensive.
To transmit or distribute a fixed amount of power at constant voltage, the conductor will have to carry more current at low power factor. This necessitates large conductor size.
The large current at low lagging power factor causes greater voltage drops in alternators, transformers, transmission lines and distributors. This results in the decreased voltage available at the supply end.