Power factor is the measure of evaluating how effectively the incoming electrical power is used in an electrical system. It is defined as the ratio of Active Power (kW) to Apparent Power (kVA).

In this article we are going to discuss* what is power factor and why it is
important in electrical system. Also what is the physical significance of power factor in power system. But* before that, we have to understand the basic concepts of Electrical power and
brief analysis of Active, Reactive and Apparent Power, so that it will be easy
to understand the concepts of Power Factor. Because the concepts of power
factor are derived from Electrical power concepts. We have already discussed the concepts
of Electrical power (Active, Reactive and Apparent Power) in our previous
Article. So please follow my previous Article about Electrical Power titled as:
**Electrical Power- Active, Reactive and Apparent Power.**

Well,
now coming to our main topic which has mainly two parts. First, *what is power
factor? *And other* *is* why it is important?*

##
**What
is Power Factor..?**

A load with power factor of 1 results most efficient loading of the system. But if the power factor is poor (say less than 0.8), then the effectiveness of usage of electrical power reduces which results in higher losses in the supply system and a higher bill for consumers.

Power factor represents the fraction of the total power that is used to do the useful work. The other fraction of electrical power is stored in the form of magnetic energy in an inductor or electrostatic energy in the capacitor.

A high power factor benefits consumers and Power Company both. Whereas Low power factor indicates poor utilization of Electrical Power and it penalize consumers.

In Electrical Engineering the concept of power factor is only
discussed in AC circuits. Whereas there are no power factor concepts in case of
DC circuit due to its Zero frequency. Its value becomes 1 (unity) for DC Circuit.
But in the case of AC circuit, the absolute value of Power Factor always lies between
the ranges **0** to **1** **(0 < Cos Î¸
< 1)**.

Generally a high and leading PF is preferred in the Electrical system. Ideally the minimum and maximum value for PF becomes 0 and 1 respectively. But in Practically, it is very difficult to achieve unity (1) power factor.

A low power factor is generally the result of inductive loads such as Induction motors, Power transformers, ballast in the luminaire, a welding set or an induction furnace. Power factor value near to 0.9 is considered as satisfactory. It is calculated with the help of Power Triangle.

##
**Power Factor Definition**

- Power factor is defined as the ratio of Active Power (kW) to Apparent Power (kVA).

P.F = Active Power(kW) / Apparent Power (kVA)

- Also
Power factor is the
**cosine**of the phase angle difference between voltage and current pharos.

Where Î¸ is the angle between V and I.P.F = CosÎ¸

- One
more way of defining the Power Factor is, It is the ratio between resistance (
**R**) and Total Impedance (**Z**) of AC circuit.

PF = Resistance/Impedance = R/Z

**Why Power Factor is Important?**

*“why Power Factor is important in Electrical System?”*What is its physical significance?

It means that only 80% of the incoming current does useful work in the circuit and 20% is used by reactive elements in the circuit. In other words, we can say that 80% of the power is useful power which is also known as real or True Power, and the rest 20% of power is Reactive Power used by reactive element in the circuit.

**[ ##eye## Discovery of Electricity]**

##
**Problem with Low Power Factor**

**50 kW**load with a power factor of unity (Reactive power = 0 kVAR) could be supplied by a transformer rated for

**50 kVA**. However, if the power factor is reduced to

**0.7 (70 %),**then the transformer must also supply additional power for the reactive load.

##
**Types of Power Factor**

**1.**

**Leading Power Factor:**A leading power factor signify that the load in the circuit is capacitive in nature. As the load supplies reactive power to the circuit, therefore in this case the reactive component

**(Q)**of Electrical power will be negative. If in the electrical circuit there is more capacitive reactance than inductive reactance, then PF of the circuit will be

**leading power factor.**In this case, the operating current will lead the voltage phasor by an angle

**Î¸.**whereas in pure capacitive circuit current leads the voltage by

**Î¸**

**= 90**degrees.

**2.**

**Lagging Power Factor:**A lagging power factor signify that the load in the circuit is inductive. As the load will consume reactive power, therefore in this case the reactive component

**(Q)**of Electrical power will be positive. If in the electrical circuit there are more inductive reactance than capacitive reactance, then PF of the circuit will be

**lagging power factor.**In this case, the operating current will lag the voltage phasor by an angle

**Î¸.**Whereas in pure inductive circuit current lags voltage by

**Î¸**

**= 90**degrees.

**3.**

**Unity Power Factor :**A unity power factor signifies that the load in the circuit is purely resistive. As the load will consume active power, therefore, in this case, the reactive component

**(Q)**of Electrical power will be zero. Hence in case of a unity power factor, total apparent power will be utilized in the circuit. In the electrical circuit, if inductive reactance and capacitive reactance balance each other, the circuit will be in resonance condition and considered as purely resistive hence PF of the circuit will be

**unity power factor.**In this case, the operating current will in phase with voltage phasor

**.**In this case Î¸ will be 0 degrees.

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Nice article

ReplyDeleteHow to improve power factor

ReplyDeleteHi Freewish4u..

ReplyDeleteThanks for your queries..

Here is very good article about the improvement of power factor..

Please go through it..

https://www.electrical-technology.com/2019/05/power-factor-correction.html

This comment has been removed by a blog administrator.

ReplyDeleteWhat happens, when power factor will be zero

ReplyDelete