Study of harmonics effects on performance of induction motors

With increasing the number of harmonics generating devices in power systems, the problem of their impact on the performance of system components like induction motors needs further consideration. Approximately, 60% of loads in all over the world are motor loads. More than 90% of these loads are consumed by three phase induction motors with a big utility factor between 0/7-0.9 in a day and most of them are used in industrial factories. So, study of their conditions under heavy harmonic polluted networks would be interesting for understanding of that how we should treat with the biggest electric load of the world. Harmonics measurement of an industrial unit is done to asset the power quality aspects in a typical factory. Then with using a lumped steady state and thermal model we analyzed the influences of different harmonics on motor temperature rise. The simulation was done with using Visual Basic linked with Excel program. The results of this simulation were compared with experimental results. New values for voltage harmonics are suggested to be considered in manufacturing procedures or in design of filter banks for induction motors. Using weighted harmonic distortion (WHD) seems to be more effective than THD that doesn't reveal the impact of individual harmonic, especially when the network has a THD bigger than IEEE criteria.