Power Quality versus Electromagnetic Compatibility in Adjustable Speed Drives

Abstract

The present approach is intended to bring off a tighter relationship between power quality and electromagnetic interference issues in electric drives. The authors opinion is that if harmonics are widely covered in power quality literature, higher frequency perturbations that inherently appear due to power electronic devices are generally neglected. The concept is developed for adjustable speed drives of wellhead induction motors from a large oil onshore extraction field. Due to the variable loads and the heavy duty cycles of the motors, the harmonics problem needed to be solved in the same time with the conducted electromagnetic perturbations. The harmonic content of the currents together with the conducted electromagnetic interferences were analyzed, mitigation countermeasures being proposed and applied.