Active vs Reactive vs Apparent Power: Learn the Differences

Power plays a crucial role in our daily lives and understanding the various types of power is essential for anyone involved in electrical engineering or energy management. In this article, we will break down each type of power, explain how they differ and provide real-world examples to help you better understand how they work. Whether you’re a seasoned professional or just starting in the field, this article will provide valuable insights into the world of power and energy. So, let’s get started and explore the differences between active, reactive and apparent power!

What is active power?

The active power is the power that is used by the load to meet the functional output. Active power performs useful work and it is the usable portion of the energy that is present in the grid. It is also called true power or real power. It is measured in watts and represented by “P”.

The following formulas can be used to calculate active power.

In DC circuits

P = V x I

In Single-phase AC Circuits

P = V x I x Cosθ

In Three Phase AC Circuits

P = √3 x V x I x Cosθ

What is reactive power?

Reactive power is the power that is supplied to the load and returned to the source, rather than being dissipated in the load. This is caused by the reactive elements in an AC circuit, specifically inductors, and capacitors which charge and discharge during normal operation. Reactive power is measured as Volt-Amps-reactive (VAr) and represented by “Q”.

The following formulas can be used to calculate reactive power.

In Single-phase AC Circuits

Q = V x I x Sinθ

In Three Phase AC Circuits

Q = √3 x V x I x Sinθ

Reactive Power= √ (Apparent Power²– True Power²)

VAR =√ (VA² – P²)

What is apparent power?

Apparent power is the total power in a circuit at any one time. It includes both dissipated (active) and returned (reactive) power. Apparent power is measured in Volt-Amps (VA) and represented by “S”.

The following formulas can be used to calculate apparent power?

In Single-phase AC Circuits

S = V x I

In Three Phase AC Circuits

S = √3 x V x I

Apparent Power = √ (True power² + Reactive Power²)

VA = √ (W² + VAR²)

The relation between true active power, reactive power, and apparent power

The relationship between these three types of power can be described using the power triangle. Active, reactive, and apparent power are trigonometrically related to each other. Each power type can be described as follows:

P (active power) is the adjacent length

Q (reactive power) is the opposite length

S (apparent power) is the hypotenuse

In conclusion, understanding the different types of power is crucial for anyone involved in electrical engineering or energy management. Active power, also known as true power or real power, is the usable portion of energy that is present in the grid and performs useful work. Reactive power is the power that is supplied to the load and returned to the source, caused by reactive elements in an AC circuit. Apparent power is the total power in a circuit at any one time, including both dissipated and returned power. These three types of power are related to each other through the power triangle. By using the formulas and examples provided in this article, professionals in the field of power and energy can gain a deeper understanding of the differences between active, reactive, and apparent power, and how to calculate them.

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