Power Quality Issues – Part 1 – Harmonics
Harmonics issues within an electrical installation frequently go overlooked due to a lack of understanding or awareness of them. This then often leads site and facility managers experiencing problems within their installations to focus on the symptoms rather than the underlying cause of those problems. In this, the first in a series of short articles on power quality issues, Julian Grant – General Manager at Chauvin Arnoux UK, explains the causes, symptoms and some solutions to the problems of harmonics.
Within the last 30 years there has been a big increase in the number of non-linear loads connected to the electrical network, including computers and associated IT equipment, uninterruptable power supplies, variable speed motor drives, electronic lighting ballasts, and LED lighting, to name just a few. The growing use of such equipment and the application of electronics in nearly all electrical loads are beginning to have some worrying effects on the electricity supply. It is estimated that today over 95% of the harmonic interference within an installation is generated by equipment within that installation.
When a linear electrical load is connected to the supply it draws a sinusoidal current at the same frequency as the voltage, however, non-linear loads draw currents that are not necessarily sinusoidal.