Research on Discharge Characteristics of Nest Material of Overhead Transmission Line under AC Voltage

With the expansion of the power grid and the improvement of ecological environment, the number of transmission line faults caused by bird activities has increased significantly, in which birds nesting is the main reason for the transmission lines trip in China. The flashover is mainly related to various factors such as the electrical conductivity of rainwater, the length of the nest material and its spatial position. In this paper, various situations of the nest material setting on the tower were simulated by changing the length and spatial position of the nest material under different conditions, and AC flashover performance of line-tower gap, where nest material was placed, was investigated. In order to study the influence of the overlapping nest material on the electric field distortion of air gap, a three-dimensional simulation model of the side phase of the llOkV cup type tower was established by using finite element analysis software. The results show that, under the fixed gap distance, the larger the conductivity of the simulated rainwater sprayed on the nest material is, the smaller the gap breakdown voltage and breakdown field strength are; In severe cases, when the gap distance between the nest material and the grading ring is 20 em, the breakdown field strength is 3.96 kV /cm, and the flashover process can be equivalent to the breakdown process of the rod-rod gap.