How about the protection range of lightning rod?
The lightning rod is composed of three parts of a receiver, a grounding lead wire and a grounding body (grounding electrode). The receiver of a lightning rod is the metal needle at the top of the lightning rod. The receiver is positioned above the protected object. The ground lead wire is the middle part of the lightning rod, which is used to connect the lightning receiver and the grounding body. The cross sectional area of the grounding wire shall be calculated not only according to the heating conditions during the passing of the lightning current, but also not to be melted due to excessive heat, and also to have enough mechanical strength. The grounding body is the lowest part of the whole lightning rod. Its role is not only to safely transmit lightning current into the ground, but to further scatter the lightning current into the ground evenly. The working principle of the lightning rod is, in essence, that the lightning rod is not a lightning rod, but uses its high position in the air to direct the lightning to itself and bear the lightning stroke.
It can protect the scope of the theory is a cone, and in the approximate point, take a 3 angle line for example. It is is a 3 angle, make a left high, 30 degrees, 30 degrees to the right, the 3 angle to 180 degrees, the cone type is that the scope of protection of the scope of his theory, which is absolutely safe, the angle is expanded to 38+ 38, this is a relatively safe. 42+42 this is considered a general bar, 45+45 or more, basically consider themselves loaded with lightning rod.
The calculation of the protection area in the ground and the calculation of the single needle protection range; in the actual work, most lightning protection projects require the lightning rod to be located on the roof of the L. Therefore, many people use the formula, regardless of the circumstances, the roof as a ground to calculate, which is not in accordance with the principle of rolling ball. The method of using the roof as a ground to calculate the protective range of the lightning rod is conditional and detailed in various specifications. The author for many years is based on the actual situation of the scene, flexible use of rolling method principle, simple and do not need to remember formula method to calculate the protection range of lightning rod. The following example: the calculation of the protection range of the 2 Radar Station Lightning receiver, the radar tower is round, the radar radome is 83.2m high, and the three lightning rod is installed at the top of the three support columns. Two types of lightning protection building, roll radius HR is 45m. Because of the high building more than HR, so the tower must adopt sideflash proof measures. For the protection of radar antenna, as long as the protection range of the lightning rod on the top and side of the radome can be calculated, the purpose of protection can be achieved.
