Real power, Reactive power and Apparent power in Electrical System

Real power, Reactive power and Apparent power in Electrical System

Real power, Reactive power and Apparent power in Electrical System

In an AC electrical system, power is not just one quantity. It’s divided into

  • Real Power,
  • Reactive Power and
  • Apparent Power

which are related to each other through the power triangle.

1). Real Power (Active Power, P)

Definition

The actual power that does useful work, like running motors, lighting lamps, heating, etc.

Unit

Watt (W) or kilowatt (kW)

Formula

P = VI cosØ

2). Reactive Power (Q)

Definition

The power that oscillates back and forth between the source and reactive components (inductors, capacitors). It does not do useful work, but it’s necessary to maintain magnetic/electric fields.

Unit

VAR (Volt-Ampere Reactive) or kVAR

3). Apparent Power (S)

Definition

The vector sum of Real and Reactive Power. It’s the total power supplied by the source.

Unit

VA (Volt-Ampere) or kVA

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