Rectifier Harmonics in Power Systems

The effect of rectifier harmonic currents on power systems is described. Rectifiers and inverters require nonsinusoidal waves of current. These current waves are made up of a number of sine waves which are harmonics of the fundamental wave. These harmonic currents can excite resonant circuits causing them to ``ring' and produce large oscillating currents. Criteria as to possible problem areas are discussed and illustrated with case studies. Examples of application of filters to ``trap' these harmonic currents are included.