ANALYTICAL EXPRESSIONS FOR CURRENT SHARE IN LIGHTNING PROTECTION SYSTEMS

In the present paper a circuit model is proposed and validated, to sim ulate a Lightning Protection System (LPS) in which the distances betwe en the down-conductors and between the successive horizontal interconn ecting rings are varied within a wide range of values. By the systemat ic application of the circuit model, solved by numerical methods, appr oximated expressions of current share functions are deduced. By means of such functions it is possible to identify how the lightning current is subdivided among the different conductors of an LPS with varying b oth the geometric configuration of the system and the typology of the grounding system. The share functions are validated by a series of exp erimental tests carried out on a real system placed on a building for its protection.