Research On The Influence Of Artificial Simulation Of Sand And Dust Weather On High Altitude Air Gap Discharge Characteristics

Sand and dust weather has been plagued most of northern China.There have been external insulation accidents caused by sandstorms in Inner Mongolia,Qinghai,Tibet and other regions.Therefore,it is necessary to explore the impact of sand and dust conditions on the discharge characteristics of air gaps.The main contents of this paper are as follows:Sampling and investigation of sand and dust were carried out in the northwest strong sandy and high-altitude areas along the transmission line corridor for a total of3200 kilometers.The particle size,element composition and salinity ratio of sand dust samples were measured by laser particle size analyzer,X-ray fluorescence spectrometer and conductivity method.Through on-site environmental investigation and related literature review,the wind speed,dust concentration,and dust concentration of the simulated dust environment were determined.Key parameters such as sand particle size,salt content ratio,and sand-dust-to-mass ratio.According to the requirements of environmental simulation,a set of sand and dust simulation experiment equipment was constructed.The equipment uses a fan and a feeder to cooperate to control the wind speed and concentration of the simulated sand and dust environment,and adopts the corona charging method to adjust the charge-to-mass ratio of the sand and dust particles.The sand and dust simulation experiment platform meets the needs of simulating extreme sand and dust storm environments.Using the artificial sand-dust environment experimental platform,a long air gap positive operation impact breakdown characteristic test was carried out in Qinghai under sand and dust conditions.The test results show that: long air gap operation under sand and dust conditions The impact breakdown characteristics have no significant changes compared to the pure air environment;the changes in the wind speed,sand-to-mass ratio,sand-salt ratio,sand-dust particle size,and sand-dust level in the sand-dust environment have an impact on the 50% operating breakdown voltage of the gap.The impact is small and can be ignored.Using the artificial sand and dust environment platform,the power frequency breakdown characteristics of the rod-plate long gap and the short gap under the sand and dust conditions were tested in Kunming.The test results showed that the impact of sand dust on the breakdown voltage of the rod-plate gap The influence is related to the gap distance.The impact of sand and dust on the short gap is more obvious.The shorter the gap distance,the greater the drop in the breakdown voltage of the rod-plate gap caused by the sand.For long air gaps above 40 cm,the impact of sand and dust can be ignored.The electrostatic field simulation of the rod-plate gap is carried out by COMSOL finite element simulation software.The simulation results show that the impact of dust particles on the space electric field is related to the distance of the gap,and the simulation conclusions are consistent with the experimental results.