已知负荷功率为P，补偿前的功率因数为cosΦ₁，需提高功率因数到cosΦ₂，所需电容器的容量Q可按下式计算:

Q=P(√1/cos²Φ₁-1-√1/cos²Φ₂-1)kvar)

也可以按照cosΦ₁，及cosΦ₂之值由下表直接查出每千瓦负荷所需补偿用电容器的千乏数，再以此值乘负荷功率P即得。

例：cosΦ₁=0.6，cosΦ₂=0.9按表查查得千瓦负荷所需补偿用电容器容量为0.85千乏，如负荷功率P＝100千瓦，则所需补偿用电容器的总容量为100×0.85=85千乏。

Pis the Power Load.The power factor before compensation is cosΦ₁,In order to increase to the desired power factor (cosΦ₂), the required capacity of capacitors(Q) can be calculated based on below formula:

Q=P(√1/cos²Φ₁-1-√1/Φcos²Φ₂-1)(kvar)

It also can be calculated based on below table. According to the cosΦ₁ and desired cosΦ₂ ,search for the value of kvar needed per kW and multiply load factor (P),then the result is the capacity of capacitors (Q),

Example:cosΦ₁=0.6,cosΦ₂=0.9 Based on the table we get kvar per kW is 0.85kvar.If the load factor,P=100kW, then the capacity of capacitor is 100×0.85=85kvar