ANALYSIS OF THE INFLUENCE OF STATIC FREQUENCY CONVERTERS ON POWER QUALITY AND THE EFFECT OF USING ACTIVE FILTERS

Abstract

The assurance of the electric power quality and the monitoring of the level of disruptive emissions determine that the problems related to the limitation of electrical disturbances become one of the important concerns of the electrical energy specialists. The paper presents both the results of a laboratory study on how the frequency converters influence the level of voltage and current harmonics at the output of the converters, and the results and conclusions of the measurements that highlight the major improvement brought to the power quality indicators by equipping with an active filter the supply circuit of a high-power electric drive powered by a frequency converter. An important conclusion of the paper is that before making the decision to mount filters to limit the level of distortion, it is necessary to make a careful analysis of the solutions regarding the reduction of distortion even at the level of the disruptive equipment. Only if these measures are not enough, the solution of using active filters, although expensive, is very effective.

Keywords

• power quality
• frequency converter
• active filter
• data acquisition
• total harmonic distortion
• true rms value