| UHV power transmission and transformation fittings in strong wind with sand areas have been exposed to wind and sand erosion for a long time,and the surface damage and fouling of fittings are usually serious.The ideal surface state of the fitting should be smooth,which can reduce corona loss and radio noise,but its actual surface state is usually difficult to ensure its ideal state during production,installation,and operation.As the fittings are installed on the ultra-high voltage transmission line with a high operating voltage level,and they are operated in harsh environments such as strong wind and sand,the actual surface state will change greatly,which may affect the surface electric field distribution of the fittings,and its actual surface state may have a effect on the corona characteristics of fittings.Therefore,studying the erosion of strong wind sand on the surface of fittings and the corona characteristics corresponding to different characteristics of the surface of fittings have great guiding significance for the design,selection and maintenance of transmission fittings in special areas such as windy sand.This article focuses on the related research of the grading ring and ball electrode in typical UHV fittings.First,collect relevant data such as wind speed,dust concentration,and sand particle diameter in areas with strong wind and sand.Then use fluid analysis software to simulate the distribution of wind pressure and flow velocity on the surface of fittings in the wind and sand flow;analyze the process of sand impacting typical fittings with ABAQUS,and obtain the impact stress and strain of the surface of fittings.Secondly,set up a wind and sand simulation experiment platform,formulate a test plan,carry out erosion and wear tests on typical fittings with strong wind and sand,and measure the surface roughness of the fitting after actual wind and sand wear with a surface roughness measuring instrument.Influence of surface roughness parameters.The measured data of the surface of the fittings were analyzed and processed,and the variation rules of the surface roughness Ra and the maximum contour height Rz with the duration of the sand action were obtained.Finally,the electrostatic field simulation is used to study the influence of the parameters of the contaminated particles on the surface of surface electric field distribution of fittings and the maximum electric field strength,and the influence of the geometric parameters,distribution locations,and dielectric constants of the contaminated particles on the electric field distribution and the maximum electric field strength is obtained.In order to verify the analysis results,different spikes were set on the surface of the actual pressure equalizing ring to simulate surface characteristics such as dirty particles and enlarged surface roughness.Corona tests were performed respectively.The corona onset voltage corresponding to different spikes was determined by UV imaging The influence of the voltage on corona onset voltage was analyzed,and the relationship between the height and sharpness of the spikes on the surface of the grading ring and corona onset voltage was obtained. |
