Power factor:
The ratio of true power to VA power, PT/PVA, is called as power factor in an alternating current circuit. If there is no reactance, ideal case, then PT = PVA, and power factor (PF) is equal to 1. If circuit contains all the reactance and no resistance of any significance (which means, zero or infinite resistance), then PT = 0, and PF = 0.
If you try and get a pure reactance to dissipate power, it is little like throwing a foam rubber ball into the gale-force wind. The ball will come right back on your face. A pure reactance cannot, dissipate poswer.
When the load, or a circuit in which you want power to be dissipated, has some resistance and some reactance, then PF will be in between 0 and 1. Which mean 0 < PF < 1. PF can be expressed as a percentage in between 0 and 100, written PF%. Mathematically,
PF = PT/PVA
PF% = 100PT/PVA
When the load has some resistance and some reactance, a portion of the power is dissipated as the true power, and some is rejected by load and sent back to source as VA power.