Power Factor Explained

Power Factor (PF) is the ratio of real power (P, in kilowatts, kW) used by a load to do useful work to the apparent power (S, in kilovolt-amperes, kVA) drawn from the grid.

  PF = P/S = cos φ = Active Power / Apparant Power

- φ = the phase angle between the waveforms of voltage and current.

• Real power (P) does the work (lighting, heating).
• Reactive Power (Q) (in kVAR) oscillates between source and load, creating magnetic fields (motors, transformers).
• Apparent Power (S) combines both - S² = P² + Q².

Layman’s Analogy - 

Imagine water flowing through a hose - 

• Real power is like the water you actually use (to water plants).
• Reactive power is when water flows back and forth in the hose without actually watering anything (only creating pressure).
• All of the water in the hose, both wasted and helpful, is known as apparent power.
• A good PF (near 1) means almost all water goes to your plants.
• A poor PF (low) means lots of water just sloshes and doesn’t water.

What Happens with Good v/s Poor Power Factor?

What can be done for Power Factor Improvement- 

• Use PF Correction Devices - Capacitor banks or smart PF controllers.
• Choose PF‑Certified Appliances - Look for motors and appliances with PF > 0.9.
• Regular Maintenance - Keep motors and compressors clean for optimal magnetics.
• Balance Loads Across Phases - (in three‑phase systems) to avoid neutral overloading.

- GGJ