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What is power factor

What is power factor

In general terms, power factor is a formula used to know the efficiency of electricity consumption at the moment of converting it into useful power, such as light, heat or mechanical movement. This formula allows measure the ratio of active power to total apparent power, so that we can know what is the capacity of a load to absorb active power and if it is resistive or if it is ideal inductive and capacitive elements without resistance. Next, we show you how to calculate the power factor and what the power factor of a photovoltaic inverter is. Continue reading for more information.

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How to calculate the power factor?

To calculate the power factor we must be clear, first of all, that this is done on an alternating current system and, secondly, knowing what measures we are going to need to carry out the formula. These are:

  • Active power (P): It is the one that is used as useful power. This is usually called, also, as real power or average power and is expressed in several (W). It is caused by the resistive elements.
  • Apparent power (S): Apparent power specifies the electrical power that is supplied to a load. It is the product of current and voltage. It is expressed in volt-amperes (VA).
  • Reactive power (Q): Reactive power is that in which the current is out of phase with respect to the voltage. The net work done over time is zero. This is expressed in kilovolt-ampere reactive hour (kVArh).

Once this has been clarified, we can go on to explain what the power factor (PF) is and how it is obtained. Power factor is an alternating current electrical system that is defined as the ratio between active power (P) and apparent power (S). This has to do with the angle that is formed between the active power and the apparent power when there is a displacement between the current wave of a load and the voltage wave, which allows us to know if the load is resistive or inductive. In the event that the wave generated was sinusoidal —when the alternating current can pass through the resistances without deforming, at 220 Hz—, the active power and the apparent power would be the same. Now, if you work with non-linear loads —when the impedance changes with the applied voltage and, therefore, the current consumed is not sinusoidal—, the way of calculating the power factor changes. In this case, the apparent power would be made up of the active power (P), the reactive power (Q) and the sum of all the powers generated by the distortion (D). Which means that the power factor depends on the active and reactive powers and the distortions.

What is the power factor of a photovoltaic inverter?

The power factor of a photovoltaic inverter is, like any alternating current system, the ratio between the active power and the apparent power at the inverter output. In an ideal situation, its maximum value is 1. This appears as one of the main measures indicated in the product specifications, along with the following:

  • Rated active power: This is the power of the inverter taking into account the phase shift between the current and the voltage.
  • Efficiency or performance: In the relation that takes place between the output and input powers of the inverter.
  • Nominal voltage: Corresponds to the voltage at the terminals at the inverter input. It is necessary for it to work perfectly.
  • rated power: Corresponds to the apparent power of the inverter that occurs continuously.
  • waveform: Finally, the waveform has to do with the sine wave of alternating current that the inverters generate. These can have a more or less proportionate wave, depending on the product.

What is the power factor for?

The power factor, as we indicated above, is very useful to know if we are facing a resistive or inductive load. This allows us to know the efficiency of electricity consumption at the time of converting it into useful power and know if we are taking advantage of energy or wasting it. To avoid wasting energy in our photovoltaic electrical installation, we must calculate the power factor and, if not, eliminate the effect of reactive currents in the installations that cause energy losses through electrical conductors due to heat and voltage drops. . In this way we can make the most of the solar panels and extract all the electricity we need without wasting it.