Binkevych T. Reliability of lightning protection systems of overhead transmission lines taking into account the influence of random factors

It was made the analysis of new and existing foreign and native systems and means of lightning protection of overhead transmission lines in modern networks of 6-750 kV. It was considered the known designs, technical characteristics and features of the operation of lightning protection devices. It was tested well-known publications based on the results of studies on the consideration of the influence of random factors in calculating the reliability of lightning protection of overhead transmission lines. The number of these publications was insignificant and the conducted analysis was confirmed with the expediency of taking into account the influence of random factors and the development of a mathematical and digital model for calculating the reliability of lightning protection, taking into account the influence of random factors. In thesis was proposed to calculate the probability of lightning strike of an overhead transmission line, taking into account a combination of random factors that would allow to adequately assess the reliability of lightning protection and increase its efficiency. The laws of distribution of random factors and ways of taking them into account when calculating the reliability of lightning protection where determined. A method for determining the area of dengerous parameters has been developed, taking into account a set of random factors affecting the reliability of lightning protection. The analysis of probabilistic assessment models for the intensity of overhead transmission line outages found in available sources revealed their significant drawback - taking into account only a limited number of random factors that determine the lightning of objects, which negatively affects the accuracy of reliability indicators and makes it difficult to optimize lightning protection schemes. A mathematical model was proposed for calculating the reliability of lightning protection, which it was taken into account all the random factors that determine the frightfulness of overhead transmission lines, and the developed calculation principles ensure that the results obtained were adequate to the corresponding natural processes. We obtained the use of numerical integration, an expression for calculating the probability of a pulsed discharge into an object, taking into account the influence of random factors. An effective digital complex was developed for calculating and evaluating the reliability of lightning protection systems for overhead transmission lines, taking into account the influence of random factors. The proposed digital complex was designed to provide reliable lightning protection for overhead power transmission lines in the Western region of Ukraine with a voltage class of 110-330 kV. On the example of the 220 kV line, calculations of the reliability of lightning protection were performed taking into account the influence of random factors on the use of various lightning protection means. Basing on the results of calculations, effective combinations of lightning protection devices were determined. It was proposed to use special chemical impurities with gelling additives, as a method of non-traditional reduction of grounding resistance. To assess the reliability and efficiency of the lightning protection systems of overhead transmission lines, taking into account the influence of random factors, it was recommended to timely diagnose the elements of overhead transmission lines, which could be performed using the developed complex.