1, reasonable selection of lightning rod Protection range calculation method.
The Common lightning rod (here only refers to the single needle) protection range of the calculation method mainly has the Polyline method and the rolling ball method.
The main features of the "Polyline method" are intuitive design, simple calculation, can save investment, but not suitable for buildings with a height greater than 20m; the main characteristic of "rolling ball method" is that it can calculate the protection range when the lightning rod or lightning belt is combined with the mesh, but the calculation is relatively complex, and the investment cost calculated by this method is larger Of these two calculation methods, the "Polyline method" is a relatively mature method, in the power system is also known as the "protocol method", that is, the protection range of a single lightning rod is a lightning rod as the axis of the polyline cone. The protection range of a single lightning rod is stipulated in the standard of overvoltage protection and insulation coordination of AC electrical devices in dl/t620-997. "Rolling Ball method" is one of the methods for calculating the protection range of flashover recommended by the International Electrotechnical Commission (IEC). The "rolling ball method" is also enforced as a method to calculate the protection range of lightning rod in the gb50057-1994z of building lightning control in China. The rolling ball method is a sphere with an HR radius that scrolls along the areas where it is necessary to prevent lightning, this part is protected by the flashover when the sphere touches only the flashover (including the metal used as a flashover) or only touches the flashover and the ground (including metals that come into contact with the Earth and can withstand lightning strikes), without touching the area that needs to be protected. In recent years, the "rolling ball method" stipulated in the national standard has also begun to be recognized by the industry, but in the actual application of the "rolling ball method" also encountered some problems, especially in the calculation of the scope of the protection of the surface lightning rod.
In general, these two algorithms have their own characteristics, the general high-rise buildings more use of the "rolling ball method."
2, with the early discharge of the lightning rod can be foolproof?
In fact, no lightning arresters equipment is foolproof, in the scope of protection is not without lightning strikes, but the lightning energy is small. From an economic point of view, to achieve foolproof will also be very wasteful, so the building lightning Protection design code and other design norms and standards have been "reduced" lightning strikes as a requirement. Therefore, in accordance with national and international standards for the design of lightning protection devices, its lightning safety degree is not 100%.
In addition to direct lightning, high-rise buildings may also be affected by sideshow mines and induction mines. The advantages of early discharge lightning rod are mainly two, one is that it can "discharge early", than ordinary lightning rod has better lightning performance. The second is to convert its early discharge time into an early discharge distance, which is equivalent to increasing the height of the lightning rod, which can increase the protection radius.
But there is still no way to protect SideShow Ray and induction Thunder.
3, to ensure that the lightning rod discharge capacity is very important.
Various lightning protection specifications require the lightning rod to have an independent lower lead grounding, so that the lightning current can be guaranteed to quickly leak into the earth.
Purchasing must not listen to the advice of some informal manufacturers, the lightning rod access to the building itself grounding system to save costs.
4, the choice of regular lightning protection manufacturers is very important.
Lightning Rod is actually a lightning needle, so lightning protection project needs to go through rigorous scientific calculation, a little carelessness may instead "lead the mine into the house." Therefore, when choosing a lightning rod supplier, it is necessary to check whether it has the professional design qualification of lightning protection Engineering and the professional construction qualification of lightning protection engineering. Domestic lightning rod market mixed, some agents of foreign brands of dealers hype their products in line with foreign advanced standards, which are true and false, it is recommended to purchase in accordance with the national standard and IEC standards to investigate products.