Dataforth has just published Application Note 129, Harmonics and Utility Costs. The objective of the 10-page document is to show how different types of harmonics in a customer’s facility affect utility-measured quantities and costs.
In today’s age of electronics, most modern electrical equipment has embedded microprocessors and electronic circuitry to increase functionality and efficiency; this type of equipment generally represents a nonlinear load resulting in non-sinusoidal line currents, which are rich in harmonics. In addition, modern LED lighting generates line current harmonics, while nonlinearities of magnetic fields in transformers and rotating air gaps create some harmonics as well.
The Application Note begins with a review of some common terms and equations used by utility power companies. The “Power Triangle” is then introduced, illustrating the relationship between the quantities KW (Real Power), KVA (Apparent Power), KVAR (Reactive Power), and PF (Power Factor) found in AC sinusoidal power distribution systems. Power Triangle equations follow, providing insight into the behavior of the Power Triangle model of energy consuming loads. This is followed by a discussion of utility billing – which is different for residential customers and commercial/industrial facilities – and the effects of harmonics created by nonlinear loads.
The conclusion leaves readers with a list of questions that electrical energy users might want to consider, such as: Do I have harmonics in my system? For exactly what quantities am I charged? How does my utility company measure billing items? How does my utility company handle harmonics?
Four appendices provide additional in-depth information. Find more details at http://www.dataforth.com/catalog/pdf/an129_Harmonics_and_Utility_Costs.pdf
AN129 Harmonics and Utility Costs joins the Dataforth library of Application Notes; the full list of offerings is available at www.dataforth.com/application-notes.aspx