Power Factor Correction Formula > Power factor correction (PFC) involves adjusting or counteracting the inductive effects of electrical loads to improve the power factor in an electrical system. The power factor is a dimensionless number ranging from -1 to 1, and it is defined as the ratio of real power (in watts) to apparent power (in volt-amperes):

Power Factor=Real Power (W)Apparent Power (VA)/Apparent Power (VA)Real Power (W)​

Power Factor=Apparent Power (VA)Real Power (W)​

The apparent power is given by:

Apparent Power=V×I

Where V is the RMS voltage, and I is the RMS current.

When the power factor is less than 1, it means the system has reactive power, and some of the energy is stored rather than consumed. In this case, power factor correction can be done to reduce the reactive power component.

Power Factor Correction Formula

The amount of reactive power (in VARs) that needs to be added or subtracted to correct the power factor can be found using the formula:

Reactive Power (VAR)=Apparent Power (VA)×sin⁡(arccos⁡(Power Factor))Reactive Power (VAR)=Apparent Power (VA)×sin(arccos(Power Factor))

Power Factor Correction with Capacitors

For an inductive load, capacitors are often used for power factor correction. The required capacitor size (in kVAR) to correct the power factor to a desired level can be calculated with:


Where Q is the initial reactive power, and desired Qdesired​ is the desired reactive power.

The desired reactive power can be calculated as:

Qdesired​=P×tan(arccos(Power Factordesired​))

Where P is the real power, and Power FactordesiredPower Factordesired​ is the desired power factor.

The required capacitance (in farads) for the power factor correction can be further calculated using the formula:


Where V is the RMS voltage, and f is the frequency of the system.

Power Factor Correction Solutions PDF

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Power factor correction is vital for improving energy efficiency and minimizing losses in an electrical system. The use of appropriate formulas to calculate the required correction allows for the design of an optimal correction system. For specific guidance and solutions, working with professionals in the field, such as Target Solar, ensures proper power factor correction tailored to individual needs.