High-risk region of bird streamer flashover in 110 kV composite insulators and design for bird-preventing shield

摘要

Bird-related flashover is a major factor of transmission line outages according to IEEE Guide for Reducing Birdrelated Outages. In recent years, with the improvement of people's awareness of environmental protection, the probability of bird streamer flashover increases especially in 110 kV transmission in China. The high-risk region of bird streamer flashover is generally believed as a circular area centred on the suspension point of the insulator at present, and many bird-preventing installations such as shield and baffle are designed according to it. However, bird-related flashover still occurs protected by such installations, the current high-risk region of bird streamer flashover and the performance of these installations may not be clear needing further research. In this paper, a simplified platform of 110 kV transmission line tower was built to simulate the process of bird streamer flashover at different dropping positions on the cross arm. The result shows that the protection radius R changes with the dropping position of bird simulation excrement. Electrostatic simulation was carried out to study the distributions of electric field during the flashover process and the experiment results are verified. High-risk region of bird streamer flashover in 110 kV composite insulators is quantitatively obtained through emulation, and the shape is more like a "flying saucer". A new bird-preventing shield with the function of "drainage" is designed accordingly, whose effect is verified and evaluated by comparison experiment.