Lightning strikes can produce different forms of damage. The International Electrotechnical Commission has called lightning disasters "a major public hazard in the electronic age." Instantaneous overvoltages such as lightning strikes, induced lightning strikes, and power spikes have become the chief culprit in the destruction of electronic equipment. From the analysis of a large number of communication equipment lightning strikes, experts believe that lightning electromagnetic pulse (LEMP) caused by lightning induction and lightning wave intrusion is the main cause of equipment room damage. The precautionary principle adopted for this is “total defense, comprehensive governance, multiple protectionâ€. Strive to reduce the harm it produces to a low point.
In order to protect the electronic network equipment in buildings and buildings from lightning damage or reduce lightning damage, the lightning protection scheme should be designed from the perspective of overall lightning protection. Comprehensive lightning protection is now adopted. The integrated lightning protection design plan should include two aspects: direct lightning protection and inductive lightning protection. Any lack of one aspect is incomplete, defective and potentially dangerous. Effective lightning protection from these aspects:
1, direct lightning protection
If there is no direct lightning protection, according to IEC1312, almost all lightning current flows through the conductor type lines (power lines, signal lines, etc.) entering and exiting the building. The damage is very serious. Therefore, direct lightning protection is used for induction. The premise of lightning protection; direct lightning protection is designed and constructed in accordance with GB50057 "Lightning Protection Design Code for Buildings", mainly using lightning rods, nets, wires, belts and good grounding system. The purpose is to protect the building from lightning strikes. Destruction provides a relatively safe environment for people or equipment within a building.
2, the protection of the power system
Statistics show that more than 80% of lightning accidents in microelectronic network systems are caused by lightning surges induced on the power lines connected to the system. Therefore, the protection of the power cord is a part of the overall lightning protection that cannot be ignored.
3. Protection of the signal system
Although lightning protection devices are installed on external incoming lines such as power and communication lines, the over-voltage induced by lightning strikes on network lines (such as twisted pair) can affect the normal operation of the network and even damage the network system. A huge transient magnetic field is generated during lightning strikes. Metal loops within 1 km, such as network metal connections, can induce extremely strong inductive lightning strikes. In addition, when power lines or communication lines transmit lightning voltage, or buildings The grounding system of the object generates a powerful transient current when the lightning strikes, and the induced overvoltage is sufficient to damage the network at one time for the network transmission line. Even if it is not a particularly high overvoltage, it can not damage the device at one time, but each overvoltage shock accelerates the aging of the network equipment, affecting the transmission and storage of data, and even the DOWN machine until it is damaged. Therefore, the lightning protection of the network signal line is a very important link for the overall lightning protection of the network integrated system.
4, equipotential bonding
The central computer room where the integrated network system backbone switch is located shall be provided with a voltage equalizing ring to electrically connect all metal objects in the equipment room, including cable shielding layers, metal pipes, metal doors and windows, equipment casings, and all metal components such as metal pipes entering and leaving the building. Connect to the equalizing ring to equalize the potential.
5, grounding
The production of lightning protection ground nets is a guarantee for the effective functioning of lightning rods, lightning protection belts and lightning arresters.
Lightning protection scheme
1. Lightning protection and overvoltage protection of power system
Since the power supply in your computer room is introduced by the building's main power distribution. The lightning protection of the high voltage side of the power supply has been implemented by the power supply department. Therefore, for lightning protection of UPS power systems, we adopt the following lightning protection schemes:
1) Lightning protection of UPS power system
From the current situation of the equipment room, the power supply line crosses the lightning protection areas at all levels. Considering the over-voltage resistance of various electrical equipment in the equipment room, we recommend the following lightning protection scheme for the power system to achieve the desired protection effect and More economical investment. Because the equipment UPS uninterruptible power supply equipment is the only important equipment for providing stable, reliable and high-quality power environment for the various electrical equipment in the equipment room, and it is the main way for the mains supply to enter the equipment room, we will supply the power supply. System protection focuses on the protection of UPS uninterruptible power supplies.
In the computer room dedicated power distribution cabinet, UPS power supply to do two levels of lightning protection. The specific protective measures are:
Level 1 protection: Install a three-phase power supply lightning arrester (single-phase power supply lightning arrester) in front of the power distribution cabinet in the equipment room.
Secondary protection: Install a three-phase power surge protector (single-phase power surge protector) in front of the UPS power supply.
Three-level protection: Install lightning protection sockets at important equipment.
2) Lightning protection and overvoltage protection of communication systems
The lightning protection of the communication system includes communication lines that are led from the outdoors to the indoors. The main lines include network communication lines, dedicated lines, microwave communication lines (antenna feeders), video lines, etc.; according to the equipment room conditions provided by you, the signal lines may be transmitted by optical fiber. So you can not do protection, but the ends of the fiber should be grounded. If there is an optical transceiver, the optical transceiver needs to be protected. If the fiber is not selected, the lightning arrester should be selected according to the type of signal line.
3) Installation and wiring
a. The role of the lightning arrester is to absorb and discharge the lightning current. All lightning protection products must be grounded.
b. The lightning arrester is connected in series/parallel between the protected device and the signal channel;
c. The input terminal (IN) of the signal lightning arrester is connected to the signal channel, and the output terminal (OUT) is connected to the protected device and is installed close to the protected device, and cannot be reversed;
d. Connect the grounding wire of the lightning arrester to the grounding bar of the lightning protection system. The shorter the wiring, the better. The length should not exceed 1m.
SMC Composite Manhole Chamber
D400 Cover,Chamber Cover,Drainage Manhole,Lockable Manhole Cover
Changxing Ro-spring Road Facilities Co., Ltd , https://www.enro-spring.com