1 & gt； Pick up the flash
Receiving lightning is to let the lightning energy in a certain range be discharged into the earth according to the channels designed by people. The safety of the ground communication station depends to a great extent on whether the lightning discharge within a certain protection range can be captured by effective lightning receiving devices and brought into the pre-designed reasonable discharge mode to the ground. Lightning rod is an active lightning receiving device, originally named as Lightning Conductor in English, originally meant as lightning rod, and its function is to lead lightning current into the earth. Lightning rod and lightning belt are developed on the basis of lightning rod. Using lightning rod is the most important and basic lightning protection measure.
2> balanced connection
When the lightning is captured by the lightning receiving device, the down conductor immediately rises to a high potential, which will cause side flashover to the wires around the lightning protection system that are still at ground potential, and make their potential rise, thus causing harm to personnel and equipment. In order to reduce the risk of flashover, the simplest method is to use the equalizing ring to connect the conductor at ground potential to the grounding device. If the distance between the metal facilities, electrical devices and electronic equipment in the station and the conductor of the lightning protection system, especially the lightning arrester, cannot meet the specified safety requirements, thick wires should be used for equipotential connection with the lightning protection system. In this way, when lightning passes, all facilities in the station immediately form an "equipotential island" to ensure that there is no harmful potential difference between conductive parts and no lateral flashover discharge. Perfect equipotential bonding can also prevent the lightning current from entering the ground and causing the counterattack caused by the rise of ground potential.
3> Landing
Grounding allows the lightning energy that has been incorporated into the lightning protection system to be discharged into the earth. Good grounding can effectively reduce the voltage on the down conductor and avoid counterattack. In the past, some specifications required electronic equipment to be grounded separately in order to prevent stray current or transient current in the power grid from interfering with the normal work of the equipment. Before 1990' s, the communication and navigation equipment in the army was mainly electronic tube devices, which used analog communication. Analog communication is particularly sensitive to interference. In order to prevent interference, the power supply and communication grounding are separated. At present, the field of lightning protection engineering does not advocate separate grounding. In IEC standards and ITU related standards, individual grounding is not recommended. American standard IEEE STD1100-1992 pointedly points out that it is not recommended to use any so-called separated, independent, computer-based, electronic or other incorrect earth grounding body as the connection point of equipment grounding conductor. Grounding is the most basic link in lightning protection system. If the grounding is not good, the lightning protection effect of all lightning protection measures can not be exerted. Lightning protection and grounding is the most basic safety requirement in the installation and acceptance specification of ground communication stations.
4> transition
Shunt is to connect a suitable lightning arrester in parallel between all wires (including power lines, telephone lines, signal lines, antenna feeders, etc.) from outside. ) and ground wire. When the overvoltage wave generated by direct lightning or induced lightning on the line enters the room or equipment along these wires, the resistance of the arrester suddenly drops to a low value, which is close to the short circuit state, and the lightning current is divided into the earth.
Shunting is the focus of the rapid development of modern lightning protection technology, and it is also the key measure to protect all kinds of electrical and electronic equipment. In recent years, almost all new forms of frequent lightning disasters need to be solved in this way. Because a small part of lightning current will still enter the equipment along the conductor after shunt, it is still very dangerous for microelectronic equipment that is not resistant to high voltage, so before the conductor enters the bushing, it is necessary to shunt this kind of equipment in multiple stages.