Research On The Characteristics Of Particle Collision And Deposition On Catenary Insulator Surface

Flashover of the catenary insulator is one of the reasons for the accidents of the external insulation of the traction power supply system.Contamination deposited on the insulator surface is the primary reason for flashover.At the same time,particle collision on the insulator surface is a prerequisite for particle deposition,so it is necessary to study the collision and deposition characteristics of particles on the insulator surface.This thesis took cantilever insulators as the research object,and analyzed the impact deposition process of particles on the insulator surface from the installation method of insulators,and used numerical simulation to study the deposition rules of particles on the insulator surface.The research results are of great significance for the operation,maintenance,and reduction of flashover accidents in the insulation of the catenary.First of all,this thesis aims at the two unique installation methods of the cantilever insulators,and establishes a collision model of particles on the surface of the insulator from a microscopic angle,and obtains the deposition conditions of particles on the surface of the flat and oblique cantilever insulators.Then,the insulator-contaminated wind tunnel model was established from a macro perspective,and the Euler two-phase flow model was used to numerically simulate the deposition characteristics of particles on the insulator surface in fluent fluid mechanics software.The contamination volume fraction on the surface of the insulator was used as a characteristic parameter for the deposition of particles on the insulator surface.Secondly,the static pressure on the surface of the insulator and the surrounding velocity distribution were analyzed.To study the effects of concentration,wind velocity,particle size,and airflow angle on the deposition characteristics of particles on the surface of a flat cantilever insulator.Finally,the differences of deposition characteristics between insulator method installation and shed structure were analyzed,and the simulation verification was performed.The results show that environmental factors has an important effect on the collision deposition of particles on the insulator surface.As the wind velocity increases,the greater the collision probability of particles on the insulator surface,and the contamination volume fraction of the insulator surface continues to increase.As the particle concentration increases,the insulator surface contamination volume fraction increases approximately linearly.As the particle size increases,the surface contamination volume fraction of the insulator increases.When the insulator is installed horizontally,the airflow angle has an important effect on the distribution of particles on the upper and lower surfaces of the shed.When the airflow angle changes from-45° to 45°,for large sheds,the contamination volume fraction on the upper surface continuously decreases and the contamination volume fraction of lower surface is constantly increasing.When the particle size and wind velocity are fixed,the exit velocity of the particles on the surface of the oblique cantilever insulator is lower than the exit velocity of the flat cantilever insulator surface,and particles in the air are more easily deposited,and the contamination volume fraction of oblique cantilever insulator is greater than flat cantilever insulator.Under the same conditions,the contamination volume fraction on the windward side of the cantilever insulator is higher than that on the leeward side,but the contamination volume fraction on the windward side of XP-70 insulators is less than that of the leeward side.It is proved that the installation method and the structure shed have significant differences in the deposition characteristics of the particles on the insulator surface.