ДОСЛІДЖЕННЯ ПЕРЕХІДНІХ ПРОЦЕСІВ У ТРИФАЗНИХ КОЛАХ З РОЗПОДІЛЕНИМИ ПАРАМЕТРАМИ ТА ЕЛЕКТРОМАГНІТНИМИ ЗВ’ЯЗКАМИ

Background. The article considers the current challenge in analyzing transient phenomena in high-voltage cable transmission lines with distributed parameters. With an increase in the operating voltage and length of such lines, the importance of accurate calculation and limitation of switching overvoltages increases, which is critical for ensuring the reliability and stability of the power system. Traditional calculation methods are often insufficient for complex systems considering mutual induction and distributed parameters, requiring the use of modern computer technologies and numerical methods. Objective. The purpose of this work is to assess wave attenuation during propagation in cable transmission lines to solve the problems of limiting lightning and switching overvoltages. The study is carried out on the example of the propagation of a rectangular voltage pulse, which allows modeling the impact of transients caused by switching and emergency modes on the cable line. Methods. Mathematical modeling based on differential equations was used to analyze voltage pulse propagation in a cable line. The equations are solved using the frequency method and numerical methods, in particular, numerical integration techniques. A two-channel system (α- and 0-channels) for a symmetrical cable line is considered to allow for the study of the influence of frequency on the characteristics of wave propagation. Results. Modeling results demonstrate the frequency dependence of propagation velocity and wave attenuation coefficients. Analysis of the pulse shape after passing a certain distance along the line reveals the similarity of distortions in the α- and 0-channels. This indicates a relatively small mutual influence between the phases, explained by the proximity of the return conductor (ground) to the current-carrying conductors of the cable. Conclusions. This study confirms the possibility of simplified analysis of overvoltages on the conductor-shield insulation without considering the interaction between the phases of the cable transmission lines. However, the analysis of overvoltages on the shield-ground insulation requires taking into account the mutual influence of processes in the shield-ground phase circuits. These results are important for developing effective methods of protection against overvoltages and ensuring reliable operation of high-voltage cable transmission lines.