Analysis and Protection Studies of Bird Droppings on the Electric Field Distribution Near 330 kV Transmission Line Cathead Towers With Composite Insulators

The increase in bird populations along the Hexi Corridor has led to an increase in flashover faults on 330 kV transmission lines caused by bird droppings. To mitigate the issue of line tripping caused by bird droppings, it is necessary to analyze the distribution of the electric field near composite insulators during the process of bird droppings falling. A three-dimensional model, including the tower, bird droppings, and insulators, was created to assess the impact of bird droppings’ characteristics on the electric field near the insulators. Based on simulation results, a bird-proof cover was designed to modify the trajectory of the bird droppings’ path. The research found that when bird droppings are grounded and continuous, the most severe distortion of the residual air gap field occurs at a distance of 599.34 mm from the insulator axis. In the dynamic process of ungrounded and continuous bird droppings falling downward with a length less than 3200 mm, the electric field intensity in the residual air gap remains below 5.66 kV/cm outside the circular area centered at the insulator skirt with a radius of 740 mm. Based on the simulation results under both single-end grounded and ungrounded conditions of bird droppings, a bird-proof cover structure was devised to alter the location where bird droppings fall. After bird droppings fall along the edges of the bird-proof cover, the average electric field intensity between the bird droppings and the high-voltage terminal is maintained below 3.02 kV/cm. These research findings lay the foundation for subsequent fabrication of physical models of bird-proof covers.