Study on the influence of wind and sand erosion on the audible noise of corona discharge in the uniformity ring of transformer bushings in 750kV substations

In order to effectively achieve corona control and precise noise reduction in various 750kV substations in the northwest region, this paper studied the influence of wind and sand erosion on the audible noise of transformer fittings corona discharge in 750kV substations. Using the outdoor test field of the Power Equipment Quality Inspection and Testing Center of Wuhan Branch of China Electric Power Research Institute as the test platform, the surface of the transformer voltage equalizing ring was polished with sandpaper of different particle sizes to simulate the surface damage state of the ring under wind and sand erosion. The starting and extinguishing voltages of the transformer hardware corona caused by wind and sand erosion, as well as the distribution law of audible noise, were obtained. The research results show that after sanding the surface of the transformer voltage equalizing ring with sandpaper of different particle sizes, the complete halo noise on the surface increases with the increase of roughness. The halo noise value after chiseling is significantly higher than that without sanding, with a difference of about 3-6dB. The research results can provide sufficient experimental basis for the selection of voltage equalization rings for substations in wind eroded areas, and have good practical value.