Investigation of the Impact of Wind-Sand Flows on the Electric Field Along Composite Insulator Surface via Multi-Physical Field Coupling

Insulators in wind-sand flows distort the electric field along their surfaces due to the wind-sand electric field, threatening the safe operation of transmission lines. This paper models the impact of wind and sand flow on electric field distribution along transmission line insulators by integrating an Eulerian two-fluid field with an electrostatic field, incorporating the electrification process of sand particles. The study investigates how different wind speeds, dust concentration, and sand particle sizes affect the electric field distribution on insulators. The results show that the electric field along the insulator’s surface decreases in steps, while the electric field forms a “U”-shape with high ends and a low center. In contrast to the clean environment, wind and sand flow generally increases the electric field. Under the influence of wind-sand flows, each 2 m/s wind speed rise reduces the electric field by about 2–3%. As sand concentration and particle size grow, the electric field decreases near the high-voltage end and increases near the grounded end. Higher concentrations or larger particles significantly boost the maximum electric field intensity, worsening distortion and increasing long-term insulation risks.