On Lightning Protection
Lightning protection is a very complex problem, and it is impossible to completely eliminate the impact of lightning overvoltage and induced overvoltage by relying on one or two advanced lightning protection equipment and measures. It is necessary to eliminate various factors that may cause lightning strikes based on the path of lightning invasion, and adopt comprehensive prevention and control measures such as grounding, voltage equalization, shielding, grounding, and shunt (protection) to minimize lightning damage.
1. The lightning protection device is commonly referred to as a lightning rod, lightning strip, lightning wire, or lightning protection network. Lightning protection means that the lightning discharge within a certain range cannot be arbitrarily selected as a discharge channel, but can only be discharged into the earth according to the prescribed channels of the lightning protection system designed by people in advance.
2. Equal pressure
If the distance between indoor metal facilities, electrical devices, and electronic equipment and the conductors of the lightning protection system, especially the lightning arrester, does not meet the prescribed safety requirements, they should be equipotentially connected to the lightning protection system using thicker wires. In this way, when lightning current passes through, all indoor facilities immediately form an "equipotential island" to ensure that there is no harmful potential difference between conductive components and no side flashover discharge occurs. A complete equipotential connection can also prevent the counterattack caused by the increase in ground potential caused by lightning current entering the ground.
3. Shielding
Shielding is the use of conductors such as metal mesh, foil, shells, or pipes to enclose objects that need to be protected, cutting off all channels of lightning electromagnetic pulse wave intrusion. All shielding sleeves, shells, etc. need to be grounded. Shielding is the most effective method to prevent the impact of lightning electromagnetic pulse radiation on electronic devices.
4. Grounding
Grounding is to allow the lightning current that has already been integrated into the lightning protection system to flow smoothly into the ground, without allowing the lightning energy to concentrate in a certain part of the lightning protection system and have a destructive effect on the protected object. Good grounding is necessary to effectively discharge the lightning energy, reduce the voltage on the down conductor, and avoid counterattacks.
5. Diversion (protection)
This is a key measure for the rapid development of modern lightning protection technology and the protection of various electronic devices or electrical systems. The so-called shunt refers to the parallel connection of an appropriate lightning arrester SPD between all conductors from outside the room (including power supply lines, data lines, telephone lines, or antenna feeder lines, etc.) and lightning protection grounding devices or grounding wires. When using shunt as a lightning protection measure, special attention should be paid to the selection of lightning arrester performance parameters, as the installation of additional facilities will more or less affect the performance of the system. For example, the connection of signal lightning arresters should not affect the transmission rate of the system; The loss of the antenna fed lightning arrester within the passband should be minimized as much as possible; If used on directional equipment, it should not cause positioning errors.
6. Avoidance
When selecting a location for building infrastructure, it is important to avoid areas with high levels of lightning or areas susceptible to lightning strikes, in order to avoid increasing the cost and expenses of lightning protection projects in the future. When lightning strikes, try to turn off the equipment and unplug the power plug as much as possible.
