How to calculate the power factor

The calculation formula of power factor is: power factor = "active power" divided by "apparent power".

Power factor is a dimensionless quantity used to describe the relationship between active power and apparent power in AC circuits. In order to calculate the power factor, we need to know the active power (P) and the apparent power (S). Among them, the active power is the power actually generated in the circuit, and the unit is Watt (W); Apparent power is the total power in the circuit, including active power and reactive power. The unit is volt-ampere times ampere (VA).

In order to calculate the power factor, it is first necessary to measure or obtain the values of active power and apparent power. Active power can be measured by power meter and other instruments, and apparent power can be obtained by measuring the amplitude and product of voltage and current.

The value of power factor can be obtained by dividing the measured active power value by the measured apparent power value. The range of power factor is between 0 and 1, and the closer to 1, the higher the power factor and the higher the power efficiency.

Power factor is usually used to evaluate the power quality in AC circuits. High power factor is helpful to reduce the load of power grid and improve the utilization rate of electric energy. Therefore, in industrial and commercial fields, measures are usually taken to improve the power factor, such as using power factor correction devices or optimizing circuit design.

Importance of power factor

Improve the efficiency of electric energy utilization: In the AC circuit, the grid will provide a certain amount of apparent power when supplying power. If the power factor is low, it means that more apparent power is needed in the circuit to meet the actual active power demand, which means that more electric energy is wasted on invalid power, resulting in low efficiency of electric energy utilization. By increasing the power factor, the reactive power loss in the circuit can be reduced, the utilization efficiency of electric energy can be improved, energy can be saved and the energy cost can be reduced.

Reduce the load of power grid: High power factor can reduce the load pressure of power grid. When a large number of circuits adopt low power factor, it will lead to the increase of current delivered by the power grid, the increase of line voltage drop, the increase of power consumption and even the voltage instability. By increasing the power factor, reactive power flow can be reduced, the load of the power grid can be reduced, and the stable operation of the power grid can be maintained.