Hold My Beer:

An ideal power factor would be 1.0, but it usually falls somewhere between 0 and 1.0. Because inductance is always changing with the load, maintaining a perfect power factor of 1.0 is impractical and often impossible.

In the following diagrams, we illustrate what leading power factor looks before and after correction, using the sine wave, beer analogy, and power triangle to explain.

Before Power Factor Correction: 

Because Power Factor is the ratio of real power, or power actually used (kW) to apparent power (kVA). A site with low power factor draws more apparent power than real power. So, if a site has a bad power factor, they will be drawing more power than they actually use, this inefficiency will increase power bills and the site’s carbon footprint. 

While reactive power is necessary for inductive loads, even if it is not used, it still remains 'unusable' and has no additional benefit to both the end user or the service provider, as it oscillates within the network as apparent power.  Click here to read more about reactive power. 

This can be better understood if we use the beer analogy: You pay per glass (apparent power) which includes the true power (the beer) and the reactive power (the foam). While some foam is acceptable, it is still unusable, and too much results in a poor return on investment. In the absence of foam, it is a reliable indicator that the beer has lost its carbonation and is therefore deemed useless.  

After Power Factor Correction: 

In order to maintain an efficient power factor ratio of 0.75, it is necessary to implement a power factor correction system that will supply sufficient capacitive power to counteract some of the reactive power within the network. Thus, increasing the amount of available true power. A beer analogy is provided below to illustrate a more acceptable glass that offers improved value for money. It is important to note that foam is an indication of an acceptable carbonation level.

How does it work?

In most commercial and industrial installations, the major problem is lagging power factor. Lagging power factor can be easily corrected by introducing a capacitive load into the system using Capacitors. A power factor controller monitors the voltage and current usage of the installation and calculates the power factor. The controller is programmed to maintain the PF within set limits; normally 0.98 lagging. As the power usage fluctuates, the controller will switch pre-set capacitor banks in and out as required.