Research On The Distribution Law Of Charged Particles In The Insulation Gap And The Characteristic Of Synthetic Electric Field Distortion Under Mountain Fire

Transmission line corridors are becoming increasingly tense,and transmission channels inevitably pass through areas with high forest fire risk with lush vegetation.Wildfires may cause the insulation strength between phases and phases of transmission lines to decrease and trip accidents occur.Aiming at the flashover problem of the insulation gap of the DC transmission line under wildfire conditions,this paper conducts research and analysis from two perspectives:the distribution of charged particles in the gap and the characteristics of the resultant electric field distortion.Through the particle charge-to-mass ratio measurement experiment,three different targets are obtained.Counting the charge-to-mass ratio of graphite particles,by establishing a temperature field-fluid field-particle dynamic field-electric field coupling simulation model,the distribution law of particles with different properties in the insulating gap is obtained,and based on the experimental measurement results and simulation data,through statistics The distortion characteristics of the composite electric field of the insulating gap under flame conditions are analyzed.This paper builds a particle charge-to-mass ratio measurement platform,which mainly includes three parts:particle charging,particle collection,and charge-to-mass ratio measurement.The charge carried by the particles is measured by the Faraday cylinder,and the particle mass is measured by the high-precision electronic scale.Its charge-to-mass ratio.Under the test conditions,the charge-to-mass ratios of graphite particles of 20 mesh,100 mesh,and320 meshes were measured,and the charge-to-mass ratio of the 20 mesh particles was measured to be 4.36×10^-05C/kg after saturation and the 100 mesh particles were saturated.The charge-to-mass ratio after charging is 1.49×10^-04C/kg,and the charge-to-mass ratio after 320 mesh particles is saturated and charged is 4.78×10^-04C/kg.The measurement results found that under the same charging environment,the smaller the particle size,the larger the measured value of the charge-to-mass ratio.Within the error tolerance range,the measured value of the saturated charge of the particles is basically consistent with the value calculated by the theoretical formula.Based on the test results of particle charge-to-mass ratio measurement,by establishing a temperature field-fluid field-particle dynamic field-electric field coupling simulation model,the movement and distribution of charged particles with different properties in the insulating gap under wildfire conditions are analyzed.Under the simulated boundary conditions,the distribution of particles in the insulating gap under three working conditions of different particle diameters,different charge polarity,and different charge-to-mass ratio are calculated.The research results show that in the vicinity of the high-voltage electrode,particles with a particle size in the range of 320 mesh account for the largest proportion,and the charge polarity has a greater influence on the distribution of particles.According to the statistical results in a single flame oscillation period,the space charge density of different partitions can be solved.Further simulation calculation considers the distortion characteristics of the composite electric field of the gap when the space charge density is considered.The calculation results show that the maximum value of the composite electric field is higher than the maximum value of the background electric field.42.976k V/m,which indicates that when the charged particles in the area close to the electrode gather to a certain extent,it will have a greater impact on the background electric field of the insulating gap.Under the same working conditions,by changing the polarity of the electrodes,it is found that the distribution of the composite electric field has a significant polarity effect,and through the distribution curve of the composite electric field,it is found that the maximum value of the electric field appears in the middle of the flame oscillation period.At this time,the gap is insulated The lowest intensity,the most prone to partial discharge and develop into gap flashover.