The models of lightning strike in general The models of lightning strike are analytical tools for making studies about protection from lightning strike in pylons and air transmission lines. The main use of these models is for making studies about protection of electric-power lines or easily affected installations (gas installations for example) from direct strike. They are also in use for determining the places for setting and dimensioning lightning rod for protection of high buildings. Why do we use these models? The reason is simple: Physical characteristics of lightning strike are very complicated and still partly unexplored and are difficult to describe mathematically. Even when we could take in consider all characteristics we would get the model, which would be very complicated for practical use. That is the reason for making some simplifications and that is how different models were created. How do we use these models? Usually these models define a mathematical term for "last permeable distance" or "pull radius" and these terms are used similarly. Using geometrical construction we are trying to determine such place and dimensions of lightning rod to achieve an adequate protection. The adequate protection is achieved when the descending leader can not reach the place with distance from the object smaller than the pull radius and distance from the lightning rod greater than the pull radius in the same time.