Power system harmonics: Part 3. Problems caused by distorted supplies

Power system waveshape distortion can come in many shapes and forms from kilohertz at the high end to hertz at the low end of the spectrum. Of these it has been found that the group most likely to cause operational problems are those of a higher frequency and in particular the notches and oscillations associated with commutation. The middle of the range harmonic distortion can lead to overheating of motors, transformers and generators and can excite system resonances; power factor correction capacitors are a prime contributor to this type of problem. Lower frequencies such as interharmonics may cause torsional torque problems on motor and generator shafts. The third paper in this tutorial series deals with these effects of power system distortion.<>