Short Answer:

Power factor correction is the process of improving the power factor of an electrical system, which is the ratio of real power used to do work to the apparent power supplied. It is usually done by adding capacitors or inductors to balance the inductive or capacitive loads and reduce the phase difference between voltage and current.

Improving power factor is important because it reduces power losses, lowers electricity bills, increases the efficiency of the system, and reduces strain on electrical equipment and the supply network.

Detailed Explanation:

Power factor correction and its importance

Introduction

In AC electrical systems, power factor (PF) indicates how effectively electrical power is being converted into useful work output. A low power factor means more current is needed to provide the same amount of real power, leading to higher losses and inefficiency. Many industrial loads, like motors and transformers, have inductive characteristics causing low power factor.

Power factor correction (PFC) is the technique used to improve this ratio, bringing it closer to unity (1), meaning more efficient use of electrical power.

Understanding Power Factor

• Power factor is the ratio of real power (kW) to apparent power (kVA).
• It varies between 0 and 1.
• Real power is actual work done, and apparent power is the product of current and voltage in the circuit.
• A low power factor (less than 1) means some power is wasted as reactive power, which does no useful work but causes additional load.

Causes of Low Power Factor

• Inductive loads like motors, transformers, and fluorescent lighting cause current to lag voltage.
• This lagging current increases apparent power without increasing useful power.
• Result is inefficient energy usage and increased losses.

Methods of Power Factor Correction

1. Capacitor Banks
   • Most common method
   • Capacitors provide leading reactive power to cancel lagging reactive power from inductive loads
   • Installed near inductive loads or at distribution panels
2. Synchronous Condensers
   • Special synchronous motors operated without mechanical load
   • Provide adjustable reactive power compensation
3. Phase Advancers
   • Used with induction motors to improve power factor at the input

Benefits of Power Factor Correction

1. Reduced Power Losses
   • Lower current reduces I²R losses in conductors and transformers
2. Lower Electricity Bills
   • Many utilities charge penalties for low power factor
   • Correcting power factor reduces demand charges and penalties
3. Improved Voltage Regulation
   • Better power factor reduces voltage drop and stabilizes voltage levels
4. Increased System Capacity
   • Reduces the load on generators, transformers, and lines
   • Allows more loads to be served without upgrading equipment
5. Longer Equipment Life
   • Less overheating and stress on electrical components
   • Reduces maintenance costs and downtime

Example

An industrial plant with many motors has a power factor of 0.7 lagging. By installing capacitor banks, the plant can improve power factor to 0.95, reducing current, lowering energy losses, and saving on electricity bills.

Conclusion

Power factor correction is the process of improving the efficiency of an electrical system by reducing the phase difference between voltage and current. It is important because it reduces power losses, lowers operational costs, improves voltage stability, and increases the lifespan of electrical equipment. Implementing effective power factor correction benefits both consumers and utility providers by optimizing power usage and reducing waste.