Effects of power harmonics and its control techniques

The pure sinusoidal wave shape generated by the electrical utilities is distorted by the harmonics produced by the increased use of nonlinear loads. These harmonics lead to adverse effects like excessive neutral current, increased distortion, transformer heating, transmission losses, interference on communication systems etc. This paper discusses the various sources of power harmonics with emphasis on UPS systems. Some experimental data of harmonic emission from, UPS systems is presented. The effects of the power harmonics and the international standards related to it are also highlighted. A few suggestions for controlling the harmonic emissions are also addressed.