What is the purpose of reactive power in electrical circuit? and what are the advantages of reactive power?

Power factor is defined as the ratio of real power to apparent power.
This definition is often mathematically represented as kW/kVA, where the numerator is the active (real) power and the denominator is the (active+ reactive) or apparent power.
So, reactive power is directly linked to the power factor of the electrical system.
in electrical system there is a three types of powers1.
Inductive power (for rotational devices eg motors)2.
capacitive power (like electronic circuits)3.
Resistive power (any resistive component in the system) In industry, to get maximum power from generation/power source it is necessary to ensure system power factor to unity (1.00).
at Unity power factor the reactive power in a system is equal to zero.
reactive power is the sum of Inductive and capacitive load power eventually from the sum of inductive load and capacitive load impedance.
Since motor is the heart of industry, normally inductive is more more higher than capacitive power in a factory.
to get unity power factor it is necessary to keep reactive power as low as possible in the system.
for better understanding please follow the links below http://www.energymanagertraining.com/announcements/EE08_result/C.Jayaraman%281%29.pdf http://www.teknatool.com/products/Lathes/DVR/downloads/How%20Power%20Factor%20corection%20works.pdf

Reactive power is essential to excite any electrical equipment . Once equipments are excited, equipments start to produce the real power. Without reactive power we can't produce the real power.

Reactive power is there to charge the magnetic circuit of elctrical system. As the industry predominantly uses lagging power factor because of huge application of Induction motor, there comes application of reactive power in picture.

Reactive power normally does not produce any work but without this system will not work.

Reactive power is that which cant be used, while active power is the power which does the useful work.

Eg: Consider the working of a motor drive system. The power which drives the load is active power while that power which produces flux in motor is reactive power.

 

Beside all these useful answers, Please note:

 

Reactive Power is somewhat related to Windings, Magnetism & Motors. So the more of these rotating Electrial equipment is present in an Electrical System the more it is used.

It practically lowers the Power Factor.

 

Hence to maintain a proper Reactive power in an Electrical System. Proper Power Factor maintenance is maintained for efficient Operation.

While reactive power does no real work.it does increases the total current flowing in the circuit.and thus increases resistive losses in the circuit.A calleague of mine liked,to relate reactive power to the foam head on beer.without the foam you beer would be flat and not taste good.but too much foam wastes capacity in the glass,the challange is to get the right amount of reactive power to serve the purpose,but not so much at to waste electrical system capacity source.

reactive power supports the voltage that must be controlled for system reliability.
Reactive power has a profound effect on the security of power systems because it affects voltages throughout the system.
regarding importance about Reactive Power and how it is useful to maintain System voltage healthy.

* generated power is a complex power which cosists of real and reactive power

* reactive power used to enhance voltage profile and improve the power factor