What is Reactive power of power system?

Answer 1

Reactive power is mainly used by big industries. To put it simply, things which store energy like capacitors and inductors take in energy then let it out as the ac voltage supply changes. The voltage is largely unafected, but the maximum currents required by the system is increased.

Short---- More current is required with reactive power, and this increases running costs. Most networks are inductive, and adding capacitors balences the system out. Big industries are charged for reactive power used but domestic users aren't. (note, reactive power is only relavent to ac circuitry and networks, not dc)

Answer 2

Reactive power is used to transfer power system (instead of dipping voltage at one end as is necessary with DC).

It is also used for voltage control. If voltage support is needed, capacitors banks are often installed - these cause the voltage to increase. On very high voltage power lines, it is often a practice to install inductors, because the line charging current (ie current due to the capacitive effect of the line to ground) can cause the voltage to increase beyond design specification. These help bring the voltage down into tolerance.

Answer 3

This is not really a practical question because power systems run at an almost constant frequency. But for equipment that runs with a lagging power factor, like induction motors, the presence of inductance in the motor windings means that the reactance would go up and the power factor down with increasing frequency. So the reactive power would increase relative to the real power.

Answer 4

Every electric loads that works with magnetic fields(i.e: motor,chokes,Transformers,inductive heating,arc-welding generators etc)produces a varying electric lags which is called INDUCTANCE.The lag of inductive loads maintain the current sense(eg: Positive) for some time and the negative going voltage tries to reverse it.These phase shift between current and voltages have to be maintained.The current and voltage have opposite sign.During this time the negative power or energy is fed to the network/circuit.When current and voltages have same sign again,the same amount of energy is required to built up the magnetic field in inductive loads.This magnetic reversal energy is called Reactive power.In AC circuit (50 Hz - 60 Hz) this process repeated 50 to 60 times a second.So an obvious solution is to briefly store the magnetic reversal energy in capacitor and relieve the network (the supply line)of this reactive energy.

Answer 5

in the absence of any power electronic devices...

the mechanical input to a generator connected to grid, will be converter to real power...

the excitation which is provided acts as a source of reactive power...

the mechanical input cannot transform into reactive power (in the absence of power electronic devices) and whatever comes in is transformed to real power. The excitation provided stores energy in the air gap of the generator, this energy sloshes between the load reactor (this is transfered back and forth between the generator air gap to load - motor air gap or capacitor or inductor air gap). This energy is not spent in any form.

thus source of reactive power is solely the excitation given to the generator.

Answer 6

Generators are designed to be able to do this to a certain degree. Output real power will decrease. Taking in vars will also decrease the system voltage. This causes the windings in the generator to heat, so too much can damage the windings.

Answer 7

Reactive power is a measure of the power consumed and returned by reactive components in an alternating current (AC) circuit, such as capacitors or inductors. It does not perform any useful work but is necessary to maintain voltage levels and support the flow of active power in the system. Reactive power is measured in units of volt-amperes reactive (VAR).

Answer 8

The effect of reactive power in generators allows the generator to maintain high voltage. Without the high voltage, the generator will be faulty or will stop working.