НАДЁЖНОСТЬ ИЗОЛЯЦИИ СТАТОРНЫХ ОБМОТОК ЧАСТОТНО-УПРАВЛЯЕМЫХ ЭЛЕКТРОДВИГАТЕЛЕЙ

Abstract

Relevance Widespread use of semiconductor frequency converters is due to the significant advantages of this technology: smoothness and accuracy of controlling the speed and torque of the electric motor, smooth start and stop; increased energy efficiency; the possibility of remote monitoring, etc. The accumulated operational experience has shown an increased failure rate of stator winding insulation of asynchronous motors operating with pulsed power. The presence of high-frequency overvoltages in the inverter signal can lead to the appearance of partial discharges even in the low-voltage motors windings. It’s leading to accelerated degradation of electrical insulation and premature breakdown. Over the past three decades, a significant amount of information has been accumulated in the technical literature: high-frequency transient models have been created; partialdischarge and corona-resistant test methods have been developed; the most important voltage parameters determining the intensity of insulation aging have been determined; regulatory documentation for testing and selection of insulation systems have been developed. Analysis and systematization of existing results are necessary to determine the directions of further research in the subject. Аim of research Identification of new solutions and trends of insulation reliability windings of lowvoltage electric machines when powered by modulated voltage. Research methods Bibliographic analysis, methods of statistical data processing. Results Analysis of the most relevant works on the reliability of low-voltage winding insulation systems in frequency electric drive systems is carried out, a bibliographic list of these works is given. The main results concerning the overvoltages simulation, insulation testing methods, studying the aging mechanisms of winding polymer insulation with pulsed power supply, determining the characteristics of emerging discharges are shown. The ways of further development aimed at modeling overvoltages, taking into account high-frequency effects, increasing the volume of experiments to estimate the insulation lifetime, studying the conditions for the occurrence of partial discharges, creating a common approach to insulation testing are determined.