COSTS AND BENEFITS OF HARMONIC CURRENT REDUCTION FOR SWITCH-MODE POWER-SUPPLIES IN A COMMERCIAL OFFICE BUILDING

Harmonic currents generated by modern office equipment cause power sys tem heating and add to user power bills. By looking at the harmonic-re lated losses in a specific electrical system--representing a commercia l building--energy costs are quantified. The analysis shows that build ing wiring losses related to powering nonlinear electronic load equipm ent may be more than double the losses for linear load equipment. Curr ent-related power losses such as I(2)R, proximity of conductors, and t ransformer winding eddy currents (I(2)h(2)) are considered. The cost o f these losses is compared to the cost of reducing harmonics in the eq uipment 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.