Improvement of soft-start method for high-voltage and high-power asynchronous electric drives of pumping plants

This paper presents a new method of soft start of high-voltage and high-power asynchronous electric drives of auxiliary units in mining enterprises, pumping stations and thermal power plants. Advantages and disadvantages of the proposed method are substantiated. The possibility of soft starting of asynchronous motors of high power from thyristors of low power has been proved. The disadvantages in the analysis of existing methods have been studied, and suggestions and solutions have been given. In soft starting of low and medium power induction motors, uses the system "Thyristor voltage converter-induction motor". In soft starting of high-voltage and high-power induction motors, a method of starting using combined low-power thyristors was proposed, taking into account the fact that the prices of high-power thyristors are expensive and that they are unreliable. A scheme of operation of parallel and series low power thyristor groups has been developed. The main disadvantage of this method is the need for uniform distribution of current and voltage values. In the paper, technical solutions for uniform distribution of current and voltage values have been developed. It was proposed to develop an improved system "Thyristor voltage converter-asynchronous motor" formed of parallel-sequentially collllected low-power thyristor groups.