Effect of Wind-Blown Sand on Switching Impulse Discharge Characteristics of Long Air Gaps in High-Altitude Environments

In high-altitude regions, sandstorms frequently occur along power transmission lines, posing significant risks to the safe and stable operation of power systems. Understanding the impact of sandstorms on the switching impulse discharge characteristics of long air gaps in such environments is therefore crucial. This study employed theoretical analysis and field surveys to identify wind velocity, charge-to-mass ratio, and particle size as key parameters for determining experimental conditions. A sandstorm simulation device was developed to create a controlled environment, complemented by a switching impulse test platform to investigate the discharge characteristics of rod-rod and rod-plate air gaps under high-altitude conditions. High-speed camera was used to capture the discharge development process in rod-plate air gaps, focusing on discharge initiation delay (DID), discharge propagation velocity (DPV), leader discharge channel diameter (LDCD), and streamer branching angle (SBA). Experimental, theoretical, and microscopic observation results consistently indicate that while sandstorms may influence the discharge process through electric field distortion, they have limited impact on the dominant factors governing breakdown characteristics. The findings provide valuable insights for improving the insulation design and protection of transmission lines in high-altitude regions subject to sandstorm exposure.