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The variation of negative corona-generated space charge related to the humidity has been systematically calculated and analysed by computational approaches. A negative fluid model in which the humidity could be adjusted was established to calculate the charged-particle density and electric field under different applied voltages. The continuity equations were solved by a flux-corrected transport algorithm and the Poisson equation was computed by the successive over relaxation method. The variations of important parameters due to humidity were discussed including ionisation coefficient, attachment coefficient, effective ionisation coefficient and electron generation rate. Each of them increases with the rise in relative humidity (RH). The particles densities of electrons, positive ions and negative ions when RH is 50, 80 and 90% were also calculated, respectively, which decreased as RH increased. [ABSTRACT FROM AUTHOR]

The tracking and positioning of transmission lines is a key element for UAVs (Unmanned Aerial Vehicles) to achieve autonomous inspection of transmission lines. Current methods are vulnerable to weather and environmental factors, have high costs, and have difficulties in data processing. Therefore, this paper proposes a transmission line tracking and localization method based on the electric field sensor array, which calculates the current UAV's heading angle deflection angle, the distance between the transmission line and the UAV, and the elevation angle, providing a new idea to solve the problem of UAV inspection of transmission lines. At the same time, the electric field distribution of different arrangements of three-phase transmission lines was analyzed using COMSOL to determine the flight area of the UAV. By comparing the electric field distribution of the UAV flight area and single-phase transmission lines, it was verified that the current method is also applicable in the three-phase transmission line scenario, and it was further verified that the sensor array used can sense the change of the UAV position in the flight area, indicating that the electric field sensor array can realize the transmission line tracking and localization of transmission lines. The experimental results showed that, in the three-phase transmission line scenario, when the sensor array moves along the transmission straight wire, the maximum absolute error of the heading angle deflection angle calculated according to this method was 8.2°, the maximum absolute error of the distance between the array and the transmission line was 19.3 cm, and the maximum absolute error of the elevation angle was 11.37°; the error was within a reasonable range and can be used for the UAV to realize autonomous inspection. [ABSTRACT FROM AUTHOR]