Research On Pollution Accumulation Characteristic Of Roof Insulator In High-Speed Aerosol And Its Influence Mechanism On Flashover

The strong turbulence environment of the roof insulator when the train is running leaves the pollutant along and around the insulator in a non-uniform distribution condition, which easily causes the roof insulator flashover. In fog and rain weather conditions, water could be gathered at the pantograph and catenary contact. When the water drops flow along the equipment, the electric field will be distorted, inducing flashover. Although roof insulator flashover in fog and rain weather condition is serious, yet recent research is not sufficient, leaving the problem unsolved, imposing threat to the safety operation of high-speed trains. Based on the rapid development of the electrical railway, it is important to investigate the pollutant accumulation characteristics and the flashover mechanism in the high-speed fluid generated by train to ensure the steady development railways.In this paper, the pollutant characteristics and flashover mechanism in high-speed aerosols have been investigated and anroof devices optimized method was proposed based on the electric field analysis.The mechanical characteristics of pollutant particles in high-speed airflow environment were analyzed, followed by establishing a multiphase fluid model to investigate the movement of the pollutant particles in high-speed wind. The adhesive property of particles on insulator surfaces was studied according to the theory of poly group fluidization. Based on the experiment, the influences of pollutant particle diameter, aerosol speed and incoming angle on the pollutant characteristics and pollutant distribution were studied. A pollution expressive method was proposed to get the distribution function. From the antifouling perspective, an optimized design was proposed by comparing different pollutant conditions in terms of insulator shed angle, distance between the shed, and the shed combination type.According to the pollutant distribution around and along the insulator surface, a residual resistance computation method was proposed. After comparing the influence of pollutant distribution around and along insulator surface on the flashover voltage and current, the flashover characteristics with different pollutant distribution on insulator surface were obtained, followed by the exploration of the flashover mechanisms.Typical pollutant situation has been collected at the Xipu section along the high-speed line between Chengdu to Qingcheng Mountain. A water loss model of pollutant was then established. Meanwhile, the electrical characteristics of pollutant during the water loss process were analyzed with experiment, with the parameter and method for contamination characterization being proposed.Based on the structural characteristics of power receiving equipment on the roof of high-speed trains, the process of water falling was analyzed from contact line and long the high voltage device to the roof. The influence of conductive water droplets on the electrical filed was studied, proposing a method to describe the electric field distortion. The influences of water distribution along the contact, dropping position, roof insulation and the speed of the train on the electric field distortion were investigated. By comparing the electric field distribution of different designs, an optimized scheme for roof device layout was proposed. Based on the analysis of pollutant composition, the influence of pollutant characteristics on surface electric field was analyzed. The electric field distribution along the insulator was discussed with the pollutant distribution similar to that of the real situation, upon which an optimized method was proposed.