What is the purpose of power factor correction in electrical systems?

• A. To increase voltage
• B. To increase current
• C. To reduce reactive power, improve voltage regulation and system efficiency, and lower losses and penalties
• D. To convert AC to DC

Answer: (C)

Power factor correction focuses on reducing reactive power in the system. Reactive power is the part of the current that doesn’t do useful work but is needed to sustain magnetic fields in inductive loads like motors and transformers. When reactive power is high, the current must be larger for a given amount of real work, which increases I^2R losses in conductors and transformers, causes bigger voltage drops along feeders, and can lead to penalties from utilities for a low power factor. By adding devices that supply reactive power locally (usually capacitors or power electronics), the net reactive power drawn from the source decreases. The same amount of real power is delivered, but with less source current, improving overall efficiency, reducing losses, and stabilizing voltage at the load. It also lowers penalties tied to poor power factor. It does not raise voltage, it does not increase current, and it does not convert AC to DC.