Research on Automatic Calculation Method of Ground Inclination and Its Error Analysis in EHV Transmission Line

The parameter of ground inclination is an indispensable key parameter in the lightning protection design. These data are obtained from the real terrain, so it is a heavy work to extract the ground inclination parameters of each tower. Furthermore, the sampling error from the ground inclination data could also cause the miscalculations in simulation results in the lightning protection analysis of transmission lines. This paper presented an accurate sampling algorithm of ground inclination, which can automatically extract multiple sampling points and accurately calculate the ground inclination data based on the elevation data from the map software. With this algorithm, the influence in the simulation caused by the sampling error of the ground inclination was analyzed, and then the suggestions of selecting sampling points were given. Finally, taking an Extra-High voltage (EHV) transmission line model as an example, the influence of inclination data and its error on the lightning protection modeling was analyzed by using electrical geometry model method. This study revealed the origin and the influence of the evaluation error of lightning shielding failure performance, and given some suggestions for the correction of ground inclination parameters in the lightning protection analysis of EHV transmission lines.