If the power factor is corrected to 0.95 lagging, keeping the receiving end MVA constant, what will be the new voltage regulation and transmission line efficiency? What can you conclude from this problem?

Due to power factor correction; voltage regulation is improved and efficiency is increased.

Explanation:

Power Factor Vs Voltage Regulation:

When the power factor is improved, the current in the system decreases as power factor and current have inverse relation.

When current decreases, the corresponding voltage drops in the system decreases as the voltage and current are directly proportional.

Since the voltage drop decreases, the voltage regulation improves since the voltage regulation is given by

Voltage regulation = (Vin - Vout) / Vout x 100%

Vout will be greater due to less voltage drop.

Power Factor Vs Efficiency:

Efficiency is given by

η = Pout/Pin

but Pin = Pout + Plosses

η = Pout/Pout + Plosses

When power factor is improved, the current decreases, the decrease in current reduces the power losses since the losses are directly proportional to the square of current (I²R) therefore, decrease in Plosses results in the increased efficiency of the system.