An Overview of Methods of Harmonic Suppression in Distribution Systems

Economic benefits from using power electronics equipment are much more visible than losses caused by harmonics produced by this equipment. Consequently, we enter the New Millenium with sources of harmonic distortion more and more distributed over distribution systems. We have to confess that we are much more effective in generating harmonics than in their elimination. This situation should not propagate into the Next Century. A more effective method of harmonic suppression is needed. Harmonics in distribution systems can be suppressed with reactive devices, switching compensators and hybrid devices built of reactive devices and a switching compensator. Selection of a method of harmonic suppression, best suited to particular conditions, requires that advantages, disadvantages and limitations of these devices, which exhibit a very broad range of properties, are well comprehended. The paper compiles and discusses general properties of various methods of reducing harmonic distortion. Such methods and devices are compared from the point of view of their effectiveness and related issues in various field situations. The paper also investigates some possibilities of new approach to harmonic suppression. In particular, the concept of a harmonic blocking compensator and a fixed-POLE resonant harmonic filter is presented.