An article by Glenn Johnson, Editor at ProcessOnline.com.au — originally seen at Automation.com —
Technology such as variable speed drives allow us to save energy from motor applications, but electrical energy efficiency is not just about speed control. Non-unity power factor loads and harmonic distortion increase energy losses in the power distribution network and increase infrastructure costs.
The effect on power network infrastructure of non-unity power factor loads and harmonics has been increasing in recent years. Previously these loads were mostly linear (direct connected motors) and with minimal harmonic distortion, but the increase in the use of inverter drives in industry and other forms of commercial and domestic electronics in the form of fluorescent lighting and switchmode power supplies for electronic equipment such as computers has led to a sharp increase in harmonic distortion, and a decrease in energy efficiency.
This article is intended as a ‘refresher’ on non-unity power factor loads, both linear and nonlinear, and why they are detrimental to energy efficiency goals.