Harmonics in commercial building power systems

Harmonics are increasingly becoming a major source of power quality problems in today's commercial power distribution systems. Although they have been present in power distribution systems since the early days of AC power systems, their level has dramatically increased and the effect on power distributions has been more and more noticeable in the last decade. This dramatic increase of harmonic levels is mainly due to the introduction of non linear loads such as personal computers, servers, variable frequency drives and UPS systems. Harmonic problems are especially common in commercial buildings housing large computer rooms where the concentration of nonlinear loads per square foot is very high, and continue to grow higher as the footprint of network and communication equipment becomes smaller. This report will provide a deep look at harmonics in power distribution systems in commercial buildings, their sources and the different ways by which they can affect electrical systems and power quality. Some of the solutions commonly used to deal with the problem of harmonics are reviewed, and a critical analysis of their effectiveness is provided. Computer simulations using Matlab Simulink have been developed to illustrate key points when possible.