Mystery in the Reactive Power ????

[mobinmk]

Hi frnds

Pls help me,
I jus learn the concept Reactive power..
But I didn't get any physical intituion.
I want to learn beyond the theoretical concepts ..
Reactive power came when the voltage wave and current wave not in phase....!!!! ( >>>Power Factor)

I didn't get the current wave and voltage wave ??
I wish to go deeply....

How Reactive power control voltage??
If Reactive power increase voltage increase
Else voltage decrease.....

Also without Reactive power, true power can't flow ,Why ??

Also This Reactive power helps to magnetisse the core of the transformer etc ????

What's the mystery in this Reactive power ,which dissipate zero power but it draw current and drops voltage..

Pls help me

 

[KlausST]

Hi,

consider the voltage to be constant ... and as phase reference.

first connect a purely resistive load, then there is current, but in phase with voltage. ( 0° phase shift)
--> apparent power = true power = U_RMS x I_RMS x cos(phi) .... here cos(phi) may be omitted, because cos(0°) = 1

* now connect a capacitor in parallel to the resistive load. Then the total current increases and you recognize a phase shift. Now the zero cross of the current is earlier than the zero cross of the voltage.
--> phase shift. (phi)
--> apparent power is increased (U_RMS x I_RMS)
--> true power stays the same (U_RMS x I_RMS x cos(phi))

Klaus