What do you mean by power factor

Aside from safety and reliability, several other goals including efficiency should be pursued in the design and implementation of electrical systems. One of the measures of efficiency in an electrical system is the efficiency with which the system transforms the energy it receives into useful work. This efficiency is indicated by a component of electrical systems known as the Power Factor. The power factor indicates how much power is actually being used to perform useful work by a load and how much power it is “wasting”. As trivial as its name sounds, it is one of the major factors behind high electricity bills and power failures. To be able to properly describe power factor and its practical significance, it is important to refresh your memory about the different types of electrical loads and components of Power that exist. From basic electricity classes, electrical loads are typically of two types; • Resistive Loads • Reactive Loads 1. Resistive Loads Resistive loads, as the name implies these loads are made up of purely resistive elements. For this kind of loads (considering ideal conditions), all the power supplied to it are dissipated for work due to the fact that the current is in phase with the voltage. A good example of resistive loads includes incandescent light bulbs and batteries. The power component associated with resistive loads is referred to as Actual Power. This Actual Power is also sometimes called as Working Power, True Power or Real Power. If you are ne...

The power factor rating is the ratio of real power (Watts) used by the load compared to apparent power (Voltage x Current drawn) into the circuit: Power factor = Watts / (Volts x Amps). The power factor value is calculated by dividing real power and apparent value. Envision a scalene triangle (shown in Figure 1) where no sides are equal and no angles are equal. The bottom of the triangle represents the real power while the hypotenuse of the triangle represents apparent power, and the third line which connects the real power and apparent power is the wasted energy due to poor circuitry. How Does this Affect Me? LUX Review gave a great example of the differences between the power factor ratings of two 20-Watt LED flood lights. The first LED flood light has a power factor of 0.95 while the other has a power factor of 0.55. The LED with a power factor of .95 would draw approximately 0.092 Amps while the LED with a power factor of .55 would draw 0.16 Amps. Therefore, if we had an electrical circuit designed for a 6 Amp circuit breaker, 65 LED fixtures with a 0.95 power factor could be installed as opposed to the 37 LED fixtures with a 0.55 power factor. While a majority of residential applications won’t require 65 LED fixtures, unless you take Christmas pretty seriously, this example is to reiterate that low power factor rated LEDs are very inefficient for larger scale commercial applications. Interestingly enough, most electric companies bill by wattage (real power). This mean...

The power factor of an AC electric power system is defined as the ratio active (true or real) power to apparent power, where • Active (Real or True) Power is measured in watts ( W) and is the power drawn by the electrical resistance of a system doing useful work • Apparent Power is measured in volt-amperes (VA) and is the voltage on an AC system multiplied by all the current that flows in it. It is the active and the reactive power • Reactive Power is measured in volt-amperes reactive ( VAR). Reactive Power is power stored in and discharged by inductive motors, transformers and solenoids • Reactive power is required for the magnetization of an electric motor but does not perform any work. Reactive power required by inductive loads increases the amounts of apparent power - and the required supply to the grid from the power supplier to the distribution system. Increased reactive and apparent power will decrease the power factor - PF. Power Factor It is common to define the Power Factor - PF - as the cosine of the phase angle between voltage and current - or the " cosφ": PF = cos φ where PF = power factor φ = phase angle between voltage and current The power factor defined by IEEE and IEC is the ratio between the applied active (true) power - and the apparent power, and can in general be expressed as: PF = P / S (1) where PF = power factor P = active (true or real) power (Watts) S = apparent power (VA, volts amps) A low power factor is the result of inductive loads such as tr...

Low power factor reduces an electrical system’s distribution capacity by increasing current flow. Therefore, having a low power factor is inefficient and expensive. But what is power factor and what affects it? A typical distribution system is limited in the amount of current it can carry; power factor, expressed as a percentage, is an indicator of the amount of total current that can be used to create work (active power). The closer the power factor is to 1.00 (100%), the lower the amount of current needed to do said work. For example, a load with a power factor of 0.80 means that only 80% of the power is being used effectively to do work. In a perfect world, all power drawn from the power system would be converted to useful work, but this is not so in the real world. To fully describe power factor, complex equations are needed. For a simpler understanding, though, the U.S. Department of Energy uses a simple analogy of the Ideally, the horse would be placed in front of the railcar to provide the most-efficient towing force; however, that isn’t always possible. The angle of the tow represents the change in power factor—the smaller the angle, the better the power factor, the larger the angle, the lower the power factor (Figure 1). 1. Angles affect useful work. The analogy shown here provides a visualization to help understand power factor. Power factor is defined as the ratio of real (working) power to apparent (total) power. If the horse is led closer to the center of the ...

Energy is needed and utilized everywhere in the world. From the point of view of convenience, efficiency and economy, it is best that we Wherever AC power is utilized, the question of power factor arises itself. Power Factor • Defined as ' the cosine of the angle between the voltage and current'. • In AC circuit, the voltage and current are ideally in phase. • But practically, there exists a phase difference between them. • The cosine of this phase difference is termed as power factor. • It can be defined and mathematically represented as follows: From the fig. (a) above, it can be clearly noted that there is a phase difference of angle ɸ between the voltage phasor and the current phasor. Power Factor = cosɸ The fig. (b) is called as Power Triangle Here, VI sinɸ = Reactive power (in VAR) VI cosɸ = Active power (in Watts) VI = Apparent power (in VA) PF = cosɸ = Active Power (W) / Apparent Power (VA) The fig. (c) is called as Impedance Triangle Here, R = Resistance, X = Reactance, Z = Impedance Z 2 = R 2 + X 2 PF = cosɸ = R/Z The Power Factor can be lagging, leading or unity. Lagging Power Factor • When current leads the voltage (or voltage lags behind the current), the power factor of the circuit is called 'Leading'. • When the circuit is capacitive, the pf is leading. • Capacitive loads such as Synchronous condensers, capacitor banks etc draw leading current. Such circuits have leading power factor. Unity Power Factor • Power factor is unity (i.e. 1) for ideal circuits. • ...

What is Power Factor? Power Factor is the ratio of the true power of a load to the apparent power; a measure of the degree to which the voltage waveform and the current waveform are in phase with one another in an electrical circuit. Leading Power Factor – A circuit in which the current waveform precedes (“leads”) the voltage waveform. CFLs can produce circuits with leading power factors. Lagging Power Factor – A circuit in which the current waveform follows (“lags”) the voltage waveform. Motors or transformers can produce circuits with lagging power factors. Non-Linear Loads – loads that change the shape of the current waveform from its original sine wave shape. This typically occurs because the load utilizes a switching action during its normal operation. Electric ballast and switch-mode power supplies (efficient power supplies used to power most modern electronic equipment) are non-linear loads. Real (or Active) Power – the energy that is transmitted to a load to do work, expressed in Watts. Reactive (or Non-Active) Power – the energy that is transmitted to a load but rather than doing work, it is stored in the load in an electrical or magnetic field. Reactive power is expressed in Vars. Apparent Power – the vector sum of real and reactive power. Apparent power is expressed in VA and is relevant to utilities because they must deliver both real and reactive power (i.e. apparent power) to the loads that are on the distribution network. Mixed Loads – An electrical circuit ...