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7 August 2019

Difference between active and reactive power

The main significant difference between the active and reactive power is that the active power is the actual power which is dissipated in the circuit, whereas the reactive power is the power which only flows between the source and loads only. Let us have a deep insight into the difference between active and reactive power in this article. 

Definition of active power:

The actual amount of power dissipated or perform the useful work in the circuit is called as the active power or true power. It is measured in watts, practically it must be measured in KW and MW IN power system.

Definition of reactive power : 

The average value of the second term in the above-derived expression is zero, so the power contributed by these terms is zero. The component which is proportional to VI sin is called the reactive power and it is defined as a Q. 

Difference between Active & Reactive power : 

  • The active power is the real power consumes by the load, whereas the reactive power is useless power.
  • The active power is the real power and is measured in watts while the reactive power is measured in VAR.
  • The active power is the product of the voltage, current and the cosine of the angle between them, on the other hand, the reactive power is the product of voltage and current and the sine of the angle between them.
  • Active power is represented in the form of a capital letter of  'P' while reactive power represented in the form of Q.
  • The wattmeter measure the active power and VAR meter is used for measuring the apparent power.
  • The torque that develops in the motor the heat dissipated in the heater and the light that emit through the lamps all these produces because of the active power. The reactive power determines the power factor of the circuit.
  • Active power must be calculated in the form of P = V*I*COS∅ ,  while reactive power must be calculated in the form of  Q =  V*I*SIN∅.
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