THE STUDY OF SAFETY DISTANCE BETWEEN TOWER AND SATELLITE DISH FOR LIGHTNING PROTECTION SCHEME USING ROLLING SPHERE METHOD

The development of a computer program for the evaluation of lightning safety distance between the tower and satellite dish is written in M-File MATLAB simulation software. The 3-Dimensional illustrative graphics model is used in order to have better understanding on how lightning protection system (LPS) works. The study of physical length of grounding electrode use on the tower is found to be significantly affecting the grounding system performances. The performances of grounding system are depending on magnitude of lightning strikes current being dispersed and the settling time for lightning strikes current is completely dispersed. The grounding system performances is studied by using lightning current impulse (LCI) generator, simulated in OrCad PSpice simulation software. It is found that the optimum length of vertical lightning rod in LPS should be the same with the striking distance. There is no significant improvement is found in lightning safety distance if the length of vertical lightning rod is higher than striking distance. The lightning strikes peak current that have larger magnitude than the withstand insulation level of specified object should cause no physical damage. It is because the lightning safety distance will also increase whenever the lightning strikes peak current become bigger. It is also found that the lower grounding impedance will produce higher magnitude of dispersed peak current and faster settling time.