Answer / deepak

Electrical machines work on the principle of conversion of
electromagnetic energy.A part of input energy is consumed
for creating and maintaining the magneticfield.This part of
the input energy cannot be converted into active energy and
is returned to the electrical network on removal of the
magnetic field. This power is known as “reactive” power Q.
The Q Power flows back and forth, causing 90º Out of phase
shift between the current and voltage waveform.This
Reactive Power has one half of the Power In the positive
area and the other half in the negative area.
Unlike true power, reactive power is not useful power
because it is stored in the circuit itself.
This power is stored by
1)Inductors,
Because they expand and collapse their magnetic
fields in an attempt  to  keep  current  constant,   
2) Capacitors, Because  they  charge and  discharge  in  an
attempt  to  keep  voltage  constant.   

Answer / vishwanth.g

hello to all, this is what i think---
this is a great question but reactive power never become
zero,may be for some <1sec or in instances.
if it becomes 0 its a great help to power system to supply
power at high efficiency to understand this u need to know
the source of reactive power,generator produces reactive and
real power p+jq,so q is due to excitation in generator ,and
P-real power is due to armature or to say rotating part of
machine.
as components get connected to GENERATOR,like
transformer,transmission line and distribution system,this
components absorbs or produce reactive power,
reactive power is a imaginary term used by engg to maintain
voltage or to say power at the load,basic thing here is
magnetic field----absorbs reactive power,electric field
---produce reactive power,
transformer----absorbs reactive power
transmission line-light loads-produce reactive power
heavy loads-absorbs reactive power
now advance in connected equipments which are all mostly
these days electronic component so reactive power is
generated i,e --static relays etc
at the end how inductive and capacitive components behaves
in power system----which was answer by many above

every answer above related to voltage quality or power
quality so i have added the basic thing to understand
reactive power movement u need to trace the sources in POWER
SYSTEM.
HOPE my answer could help some one

Answer / jnanesh

80% of our industrial loads use inductive loads i.e
induction motors .These inductive loads require reactive
power which plays an important role in maintaining magnetic
field inside the motors.so reactive power is necassary but
should be in a limit which in otherwise increses losses

Answer / gobi

AC power can be classified in to active power and reactive
power.
importance of reactive powers are to Maintain and control
the voltage balance on the system, Avoid damage to the
Transmission System, Generation plant and Other connected
parties•
The provision of Reactive Power by all Generation Units for
voltage support is vital to maintain a secure and stable
Transmission System.
If reactive power is zero then the power factor will be
maximum that mean full utilization of power.Maximum power
utilization is the basic necessity for power system.

Answer / p.karthik meiyappan

reactive power is one of the important one in transmission
,during transmission the real power voltage drop occurs so
in order to boost up the voltage level,reactive power are
supplied at the receiving ends of the transmission lines
also in order to reduce the losses in the transmission line

Answer / alpesh surat

i agree with gobi with little addition..
• reactive power Results from energy storage elements in the
power grid (mainly inductors and capacitors)
• Has a strong effect on system voltages
• It must balance in the grid to prevent voltage
problems
• Reactive power levels have an effect on voltage
collapse
& we need var compensation also if u know.if reactive power
zero then we get pure reactive power(unity power
factor).but in actual reactive power is zero not possible
as inductive & capacitive element ar present.

Answer / deepak

Importance of REACTIVE POWER:
Electrical machines work on the principle of conversion of
electromagnetic energy.A part of input energy is consumed
for creating and maintaining the magneticfield.This part of
the input energy cannot be converted into active energy and
is returned to the electrical network on removal of the
magnetic field. so this requirement of magnetic field by
machines is met by REACTIVE POWER.
what happens when reactive power is ZERO.
when the connected load to the system is purely Resistive
reactive power generation vl b ZERO.

Answer / raja rankesh ranjan

i agree with Mr. Vishvnath.g but if it is reactive power is zero then power transfer capacity of transmisn is low.

Answer / vivek gohane

what ever be the power generated by the generator, that is
used by the consumers i. e.lighting loads,ind.motors,arc
furnaces and all these loads works on lagging power factor
so if it is zero means no reactive power flow ie.load
didn't get reactive power so it will not run or work
satisfactorily. 1) if we think about gen,then it is under
excited condition for generator so terminal voltage of
generator will decrease and current will increase.2)we know
all the generator are connected together with grid if
reactive power flow of any one generator become zero then
it has adverse effect on other generators,resulting in
power loss,heating effect and many more.

Answer / girish kumar samal, hindalco,h

it is a serious case. system vltage goes down. as we have
many inductve load. if there is only resistive load or
impedance of the system is minimum (near= 0)
then its ok.

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