![]() Lightning discharges between charged clouds and the Earth’s surface are responsible for considerable damages and casualties. Nature Photonics volume 17, pages 231–235 ( 2023) Cite this article The very high electric field E (kV / m), which appears in that zone, produces a circulation of ascending electric charges through the body of the lightning conductor of the opposite sign, initiating an ascending tracer, which will meet and recombine with the descendant leader, capturing it and unloading it to the ground. This high voltage is the trigger to start the leader descended from the beam, which will drill the dielectric air between the cloud and the ground. In storm conditions, high voltage occurs between the cloud and earth system due to the large number of electrical charges that are present both at the base of the cloud and on the ground. In order to capture this discharge, the lightning rod has a tip and a metallic body, which are connected by a conducting network to a low impedance earthing system (less than 10 Ω) where the lightning discharge dissipates. That way, the lightning rod needs to be installed over the highest point of the building or structure we need to protect it will be in charge of capturing and safely conducting the lightning discharge to the ground. When people ask us, Hus, does a lightning rod work? We indicate that it’s an air terminal that gives external protection to a building or structure from direct lightning strike impacts. The thunderbolt also has two very characteristic associated effects: the lightning, which is its luminous effect due to the high current circulation (up to 200 kA) and the thunder, which is the sound effect due to the expansive wave of the air that is heated in a few microseconds to a high temperature. ![]() And other regulations, which establish safety procedures for risk reduction when we are outside a structure or building (IEC / TR 62713). There are also international regulations that deal with the effects of lightning current on the human body and livestock (IEC TR 60479-4: 2011). ![]() To combat and mitigate those effects, the regulations for protection against lightning establish safety measures for people and animals, such as those drafted in Annex D of the UNE 21186: 2011 standard. On the other hand, the physiological effects mainly affect living beings and occur due to the step and contact voltages that appear when the lightning is discharged to earth. Thermal effects occur due to the high temperature reached by the channel through which the lightning current flows it may reach up to 20,000 ☌, which causes great damage when the electric shock reaches, for example, a tree or impacts a structure. Due to their importance, we will emphasize the thermal and physiological ones. Among the different effects that can produce lightning strikes, we can mention some of the thermal, physiological, electrodynamic, electrochemical, etc. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |