Radio Interference Characteristics Of Bundle Conductor On AC Powerline In High-altitude Area Under Sandy And Dusty Weather Conditions Based On Corona Cage

Compared with UHV and lower voltage level power lines,the electromagnetic environment on UHV power lines is much stronger,leading to the more prominent corona effects.It is also the key index in the design and construction of UHV projects,especially the RI(radio interference).In northwest China,the sandstorms occur frequently,the existence of sand particles will affect the radio interference.However,there are seldom researches on radio interference of power lines under sand and dust weather.In this paper,the RI measuring system under sand and dust conditions is set up in high altitude area.Using UHV AC corona cage,the 0.5MHz components of high frequency corona current pulses for 23 types of bundle conductors commonly used in AC power lines are experimentally investigated.and the effects of conductor parameters and dust factors on RI of bundle conductors are analyzed and discussed.The RI testing system under sand and dust conditions in high-altitude area was developed,and the required dust parameters for the test were obtained based on the meteological parameters in sandstorms near the actual 750 kV power line in northwest China.Three different range sizes of sand particle and the appropriate dust concentration were selected.According to the requirement of dust coverage for the test,a sandy and dusty weather simulation system matched the size of the UHV corona cage is determined.According to the test conditions,the RI measurement method suitable is determined and the corresponding measurement system is built.The influencing factors of RI under sand and dust conditions in high altitude are studied,including the effects of the field intensity,sand particle size and dust concentration on RI.Furthermore,the correction method for calculating the and the excitation function under the conditions of sand and dust in the high-altitude area is proposed,and the formula is tested for significance.The RI level of UHV AC single-circuit and double-circuit power lines on the same tower under sand and dust conditions is predicted.Based on the 2-D theoretical model of RI,the characteristics of RI level from coordinate center to surrounding direction were obtained.