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Electrical machines are widely used in various branches of the national economy. In particular, electric motors are one of the main elements in electrical power generation systems. The electric machines used at this ensure reliable operation of individual power units and the entire power supply system in general. The reliability of engines’ operation is largely determined by the quality of its insulation, that is why the improvement of methods for controlling the isolation of high voltage asynchronous motors is an actual task. The aim of the research is to develop a method of continuous automated control of electric insulation condition in stator windings of an asynchronous motor basing on the analysis of experimental and industrial operation data making it possible to estimate the dynamics of changes in the main insulation parameters. The main elements showing reliability of high-voltage electric machines, applied electro-insulation structures, methods for controlling insulation resistance in a high-voltage electric motor are considered in the article. The research performed was based on the results of the experimental and industrial operation of the automated system of insulation control under working voltage at the real facility carried out by the group of companies «Energopribor» of the town of Cheboksary. The analysis of existing methods for insulation control is given, the scheme of insulation control by superpositioning test current with the frequency which is different from industrial one. The authors propose the method to estimate the dynamics of resistance changes in insulation of stator windings of the asynchronous motor, to reveal its approximation to the maximum permissible state in the process of operation and in reserve shutdown. Software modeling was carried out, the results of which correspond to the data of experimental and industrial operation. The results obtained during the research allowed to systematize the obtained experimental data, to modernize the hardware part of the diagnostic complex DUKAT-SCAD, to outline the criteria area for its applicability. |
