REAL POWER , REACTIVE POWER & APPARENT POWER WITH POWER FACTOR

THERE ARE THREE TYPES OF POWER GIVEN BELOW

KW - It is the power that actually power the equipment & performs useful work.

2. REACTIVE POWER/

KVAR - Non Useful Power but required to maintain and produce magnetic field/capacitor charge in magnetic equipment (relay, motor, transformer).

3. APPARENT POWER

KVA - It is the Vectorial summation of KVAR & KW.
or
Total power (Active+Reactive) drawn from the system. This determines the total load (current) on the system. 
                  
For calculate KVA , we have to determine Vectorial Summation of KVAR & KW, Look at angle between these vector.  
        
             KVA =  KW + KVAR

           ****************
Now , Let's see What is power factor ?

POWER FACTOR

PF is the ratio of Real power to Apparent power.

    PF = Real power / Apparent power

    PF = KW / KVA     ( where KVA = KW + KVAR)

so,  PF = kw / ( kw + kvar)

                       or

  PF = COS (angle between KW & KVA in power triangle)        
                   or

  PF = SIN (angle between KVAR & KVA in power triangle)

where ,   From Power Triangle

                KVA² =  KW ² + KVAR²