Transmission Line Lightning Trip Risk Distribution Map Rendering Method and Its Validity Verification

In order to reflect lightning trip risk of the regional transmission grid more directly,we define a transmission line lightning risk based on the lightning location data and set up a lightning trip risk assessment model according to the calculation model of transmission line trip rate.Based on the law of tower back flashover and the improved electrical geometric model of transmission line shielding,the new model calculates the risk of transmission lightning trip in accordance with the combined effects of the lightning parameters and topography parameters.In the calculation,according to the spatial distribution characteristics of lightning parameters and topography parameters,the target area is divided into several small grids with the grid method,and the lightning trip risk of each small grid is calculated using the statistics of grid flash density parameters in the mainland,surface inclinations and typical tower parameters.Moreover,by using the natural segmentation method,the grids are divided into several corresponding risk levels that are labeled by different colors,and format the lightning risk distribution map of the regional transmission grid.Correlation analysis shows that the lightning trip risk distribution map is more relevant than the ground flash density distribution map to the lightning trip failure point distribution map of transmission lines.