Electrical engineers use the term "power factor," which quantifies how well a system uses electrical power. This indicates the efficiency with which electrical energy is transformed into productive work by showing the real power to perceived power ratio. The amount of power that operates an electrical circuit is referred to as active power, often called real power. However, reactive power does not accomplish any beneficial work. Rather, it rotates between the source of power and the load as a result of inductive or capacitive loads. Reactive and active power added together provide the circuit's apparent power, which is the overall power applied.

In this blog, we will understand the concept of power factor along with its various other power sources.

What is Active Power?

In an AC circuit, active electrical power is the usable or used electrical energy measured in watts (W) or kilowatts (kW). Another term for active power is "true power," or "real power" and this is the kind that heats LED lights, lightbulbs, and other devices in a meaningful way.  

To put it simply, the genuine power that is really delivered to the load such as transformers, induction motors, generators, etc. and wasted inside the circuit is known as active power. It is measured in the parameter known as Watts, and the symbol denoting Watts is W. Active Power can work efficiently in both DC and AC circuits.   

Formula of Active Power

Active power is computed by measuring the electric current circulating in phase with the applied voltage. Real power or active power is the outcome of voltage and current flowing in phase with voltage.

DC Circuit

DC circuits lack the angle of phase between the current and the voltage, so power in DC circuits is determined by multiplying the voltage throughout the load and the amount of current passing through it. Or to put it another way, the current and voltage are in sync with one another. That is, they begin at the same moment to arrive at the peak and then simultaneously return to zero.

Formula: P = V x I 

Where,

P = Power

V= Voltage

I = Current

AC Circuit

On the other hand, in AC circuits, the phase angle between the voltage and the current is represented by the addition of cos theta

For a single phase

Formula: P = V x I x cos theta (difference)

For three phase

Formula: P = v3 x V x I x cos theta

What is Reactive Power?

Reactive energy is the power that moves both from the origin to the load and vice versa. It can move in both directions. Kilovolts ampere reactive or kVAR is the unit of measurement for reactive power.

The reactance current from the inductive load causes the current to lag after the applied voltage. Because of the reactance of the capacitive load, the voltage being applied is the result of the current leading to the applied voltage. The voltage and current will always move in phase when there is both a capacitive and reactive load.

Both positive and negative flow of power are possible under reactive power. Power flows are classified as positive or negative depending on whether they are coming from the source or the load. Reactive power, which is often exclusively defined for AC circuits, is represented by the letter Q and constantly oscillates between the source and the load.

Formula: Q = V x I x sin theta

What is Apparent Power?

Both volt-ampere and kilovolt-amperes (kVA) are used to denote this power, which is the result of combining reactive and active power. The majority of loads encountered in the day-to-day activities of an individual combine resistive and inductive elements. The entire power given by the source is known as apparent power. The amalgamation of active and reactive power is consumed by the resistive load and reactive power by the inductive load.

Formula: S² = P² + Q²

Where,

S = Apparent Power in kVA,

Q = Reactive Power in kVAR

P = Active Power in kW

What is True Power? 

The power used by motors, lighting, and other equipment to provide meaningful work or heat energy is known as true power, and it is expressed in watts or kilowatts. The resistive component of the main circuit that does the work is called true power. Only if the voltage and current are either equally positive or negative, true power can be generated. Some currents do not generate work that is beneficial if the voltage and current are out of phase. There are no real pure resistive circuits, only theories. Since the circuit wires themselves generate some inductance and capacitance, fully resistive circuits do not exist in real-world scenarios.

Many loads exhibit minimal induction and capacitance and are primarily resistive. These loads have ratings in watts (W) and draw actual electricity. As such, it is acceptable to disregard the reactive component and only designate resistance loads in volts or kilowatts.

Formula: P = I²R

                P = V²/R.  

What is Complex Power?

Complex power is the summation of real and reactive power. Complex power offers a comprehensive understanding of power flow within a circuit by incorporating both the electrical power's phase and magnitude angle in a circuit. It is expressed as a complex number where the real part stands for active power and the imaginary part represents reactive power. Both the energy required to complete tasks and the power stored and released by inductive or capacitive components are considered complex power. Complex power makes it easier to analyse the quality of power, efficiency, and system behaviour in electrical networks by considering both factors. Comprehending complex power is crucial for maximising energy efficiency and guaranteeing the steadiness and dependability of electrical infrastructure.

Read Also: Unveiling Power Factor Correction Capacitors: Their Purpose And Importance

Conclusion

To sum up, the power factor—which includes apparent, true, complex, reactive, and active power—plays a crucial role in the field of electrical engineering. It is an essential indicator for evaluating the effectiveness and functionality of electrical systems. Engineers can maximise energy efficiency, minimise waste, and raise the general dependability of electrical networks through the comprehension and optimisation of power factors.

The percentage of power used to do work is known as active power, whereas reactive power is the reflection of energy oscillation that does not create work. Both dynamic and reactive components are combined to provide apparent power, which gives a system-wide picture of all the power required. True power factor provides information about the actual efficiency of power utilisation. It is calculated as a cos of the angle of phase between voltage and current. The quality of power and system behaviour can be better understood by taking into account the phase angle and magnitude components of complex power factors.

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