A.D. Polykrati, M.P. Paisios, P.T. Tsarabaris, C.G. Karagiannopoulos, and P.D. Bourkas (Greece)
Protection radius, lightning rods, striking distance. Lightning has disastrous consequences from direct or indirect strikes and is responsible for human and animal deaths, permanent or impermanent
At the base of the cloud a negative charge is building up, causing a positive charge rise on the ground. The negative downward stepped leader approaches the ground, so that the field strength of the ground surface increases (E > 5 kV/m) and takes its maximum value. The positive upward streamer moves towards the downward opposite charge, causing a breakdown of the air's resistance at the point of their meeting. The lightning strikes on this point. The electrical spark, which is formed when the lightning discharge occurs, usually has values of electrical current in the region of 5 kA and 400 kA. The transfer of cloud charges towards the ground occurs in consecutive steps, each of which lasts about 1 s and has a length of some ten meters. The intervals between the above steps are in the region of s [4, 11, 12]. According to the results presented in this work, lightning pulsed excited rods, seem to have a greater protection range than Franklin types. Besides, for increased reliability reasons, the considered protection radius is restricted in practice. The aforementioned assumptions are supported by the corresponding French standard concerning lightning rods with pulsed excitation.
Important Links:
Go Back
