Costs and benefits of harmonic current reduction for switch-mode power supplies in a commercial office building

Abstract

Harmonic currents generated by modern office equipment cause power system heating and add to user power bills. By looking at the harmonic-related losses in a specific electrical system-representing a commercial building-energy costs are quantified. The analysis shows that building wiring losses related to powering nonlinear electronic load equipment may be more than double the losses for linear load equipment. Current-related power losses such as I/sup 2/R, proximity of conductors and transformer winding eddy currents (I/sup 2/h/sup 2/) are considered. The cost of these losses is compared to the cost of reducing harmonics in the equipment design. Results show that an active-type harmonic elimination circuit, built into the common electronic equipment switch-mode power supply, is cost-effective based on energy loss considerations alone.