The relationship between the power components of an AC electrical system can be represented with a right angled triangle which is referred to as the power triangle.
It basically represents the three electrical concepts; namely,
- Active Power
- Reactive Power
- Apparent Power
Active Power/True Power/Real Power
It is the actual amount of power consumed or dissipated by an AC circuit system. It is measured in the unit of kilowatts (kW). It is basically the power consumed by the resistive elements in an electrical power system. When an AC electrical circuit consists of only resistive components, their voltage and current waveforms will be in phase. That is at every instant the product of current and voltage will be zero. It means that the direction of flow of energy is only towards the load side and not towards the supply side. This net power is referred to as the true power.
Reactive Power/Phantom Power
When reactive loads such as inductors and capacitors are present in an AC circuit along with resistive components, the total voltage tends to lag/lead the total current waveform. The net power in this circuit tends to flow back and forth directions(to the load side and the supply side). This power is called the reactive power. It is measured in kilovolt-Ampere Reactive (kVAR). Reactive power just heats up the conductors and generates energy losses.
Apparent Power
It is basically a combination of active and reactive power. It is basically the product of RMS values of voltage and current. It is measured in kilovolt-Ampere (kVA).
Power Triangle
Using the Pythagoras theorem, the power components are expressed as,
The phasor representation of these power components can be implemented with a right angled triangle which is shown in Fig. 1.
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| Fig 1. Power Triangle |
The angle between the hypotenuse and adjacent side is called the angle of power factor(Ø).
In AC systems, the power factor of an electrical system is basically a factor of its efficiency. If an equipment is said to have 0.9 power factor, it simply implies that it is 90% efficient. "Unity power factor" is the goal of any electrical industrial facility. If the power factor is falling below 1, they are needed to supply more current to the consumer or should be able to provide equipment with more efficiency.
