Ток молнии, кА - Lightning current, kA
This is a desperate measure. As it was mentioned, the specialist is interested in the breakthrough probability of the lightning having the hazardous current rather than in a breakthrough probability of the lightning to the protected facility as it can be estimated using a special calculation software. The results shown in Fig. 9 for a facility 30 m high, can be repeated also for any other height, and then the estimate of the lightning collection radius with the set current Rat(IM) according to the equal distance principle based on the calculated orientation height value HO(IM) can be made.
We cannot see any special calculation problems. A series of computer calculations has shown that value Rat/h although it varies along with facility height h, it still remains within a rather limited range. Thus, for the lightning having a linear charge of the average value (0.5 mC/m), the change in the structure height from 15 to 60 m (typical civil engineering) reduces ratio Rat/h from 4.5 to 3.5. This is not very important for estimates of the expected lightning strike number.
The situation is much worse with the estimation of the lightning breakthrough probability pass the lightning arrester to the protected structure. We have no doubts in that a particular location of the lightning strike in the "lightning arrester and facility" system is defined by the competitive development of opposed leaders from them.How Does A Lightning Orient and Can We Control This?