This paper has realized the statistics of transmission
line ground flash density based on grid method. The data
for this analysis is acquired through the interface of a
lightning location system (LLS). First, a buffer zone
along the transmission line with the radius R (about
1-3km) is created and the buffer zone is divided into
many grids whose lengths are almost equal. Then the
lightning cloud to ground flash number N; and the area S;
is calculated for each grid, respectively. So the ground
flash density of each grid can be given as[13]: