Short Answer:

Power factor correction is the process of improving the power factor of an electrical system to make it more efficient. Power factor is the ratio between real power (used for work) and apparent power (total power supplied). A low power factor means more current is needed, which increases energy loss and reduces system efficiency.

To correct the power factor, devices like capacitors or synchronous condensers are added to the system. These devices help reduce the phase difference between voltage and current, leading to lower energy losses, reduced electricity bills, and better utilization of electrical equipment.

Detailed Explanation:

Power factor correction

In an electrical system, power factor is a measure of how effectively electrical power is being used. It is defined as the ratio of real power (kW), which performs useful work, to apparent power (kVA), which is the total power supplied. Power factor is usually expressed as a number between 0 and 1 or as a percentage. A power factor of 1 (or 100%) means all the power is being effectively used, while a lower power factor indicates inefficiency.

In many systems, especially those with inductive loads like motors, transformers, and fluorescent lights, the power factor is less than 1. This happens because inductive loads cause the current to lag behind the voltage, leading to the presence of reactive power (kVAR) that does not perform any useful work but still adds to the total power supplied.

Why Power Factor Correction Is Needed:

A low power factor means:

More current is drawn to deliver the same amount of real power
Higher losses in cables and transformers (more heat and energy waste)
Lower system efficiency
Increased electricity charges, especially for industries where power factor penalties are applied
Overloaded electrical infrastructure, requiring larger cables and transformers

To overcome these issues, power factor correction (PFC) is done by adding capacitive elements that produce leading reactive power. This helps neutralize the lagging reactive power caused by inductive loads and brings the power factor closer to 1.

Methods of Power Factor Correction:

Static Capacitors:
Simple and cost-effective method. Capacitors are connected in parallel with the load to provide leading current that cancels out lagging current.
Synchronous Condensers:
These are synchronous motors running without mechanical load. They supply reactive power and improve the power factor dynamically.
Automatic Power Factor Correction (APFC) Panels:
Used in industries, these are control panels with a bank of capacitors and relays that automatically adjust the number of capacitors connected based on the system’s power factor.
Phase Advancers:
Used for correcting the power factor of induction motors, especially in heavy industrial applications.

Advantages of Power Factor Correction:

Reduces electricity bills by minimizing reactive power demand
Improves voltage level and system stability
Reduces losses in transmission and distribution systems
Extends the life of electrical equipment by lowering heat and stress
Frees up capacity in transformers and cables for other loads

Where It Is Applied:

Industries with large motors or welding equipment
Commercial buildings using HVAC systems
Power distribution networks to maintain system stability
Renewable energy systems like solar inverters

Example:

If an industrial unit has a power factor of 0.7, it means only 70% of the power drawn is being used effectively. By installing capacitors, the power factor can be improved to 0.95 or above, reducing current, losses, and overall energy cost.

Conclusion

Power factor correction is a simple but very important technique to improve the efficiency of electrical systems. By reducing the amount of reactive power and bringing the power factor close to unity, it helps lower losses, reduce energy costs, and extend equipment life. Especially in industrial and commercial setups, power factor correction plays a vital role in maintaining system performance and saving electricity.