Application of Lightning Protection Grounding Engineering for Network Room in Zhengzhou
First, citation lightning storms are serious natural disasters that humans are still unable to resist. Incidents caused by lightning and casualties and equipment damage have occurred frequently. With the acceleration of China’s informatization process, computer networks have become more widely used. In particular, the integrated business system has been on-line and the flat data management has been implemented. The computer network’s security and stability requirements have been extremely high. As the center of data processing and hubs, it has become an important protection target in information systems. In the computer center, there are many equipments, and power lines, communication lines, and data lines cross each other, and they are vulnerable to induced lightning strikes. Therefore, lightning protection in the engine room is a problem in system integration. The problems that must be considered in the future are briefly discussed and analyzed in light of the actual application of lightning protection in the engine room.
Second, the engine room lightning protection principle:
Introduce most of the lightning current directly into underground leakage (external protection); Blocking overvoltage waves introduced along power lines or data lines, signal lines Harm the equipment (internal protection and overvoltage protection); Limit surge on protected equipment Voltage amplitude (overvoltage protection). The above three lines of defense are mutually compatible and each one of them is indispensable. When we are doing protection, we should make full use of the external protective facilities of the building itself and consider the protective elements in the equipment room. We only focus on the discussion of the inside of the equipment room. Protective elements.
Third, the type of lightning:
1.
Direct lightning strike lightning over-current directly hit the building where the device is located or device connection line and through the network equipment into the ground is called direct lightning, direct Lei Lei contains great energy, voltage peak up to 5000KV, with great destructive power, If a building is directly struck by lightning, huge lightning currents flow down the ground and cause the following three kinds of destructive effects:
A. A huge lightning current flows into the ground in a few microseconds, causing the ground potential to rise rapidly, causing a counterattack and endangering personal safety and equipment safety.
B. Lightning currents generate powerful electromagnetic waves, and extremely high pulse voltages are induced on the power lines and signal lines, thereby causing devastating damage to the settings.
C. Lightning currents flow through electrical equipment and generate extremely high heat, causing fire or explosion.
2.
Lightning strikes lightning strikes on the line or the extremely high voltage generated by electromagnetic induction is transmitted from the outdoor power line and communication line to the building, damaging the electrical equipment.
3.
Lightning induced by the lightning current electric current generated by the conductor over-voltage, over-current caused by the lightning strike is called inductive lightning, through the power line, signal feeder induced lightning voltage intrusion computer network system, high pulse voltage, peak up 50KV, resulting in a large area of ​​network system equipment damage.
Fourth, several ways of lightning damage to network equipment:
Lightning attacks on computer network systems mainly have the following three ways:
(1) Directly striking the lightning through the building's air-termination device (Franklin lightning rod, lightning protection zone) discharges the lightning current into the ground, resulting in tens of thousands of volts of ground network ground potential. The device ground wire invades the network equipment to form a ground potential counterattack.
(2) When a lightning current enters the ground along a lightning deflector of a building, a strong magnetic field is generated around the down conductor, and an overvoltage is induced on the metal pipe (line) around the down conductor. The power is transmitted through the network system. Or signal lines invade the network system.
(3) Power lines or communication lines that enter or leave the building, and lightning voltages and overcurrents that are loaded by direct lightning or induced lightning outside the building break into the line and infringe the network equipment.
It can be seen that thunder and lightning mainly invade computer network systems through power supply lines, communication lines and grounding systems. Therefore, the lightning protection of the network system is mainly aimed at the above-mentioned three possible lightning protections. By increasing the lightning protection facilities at all levels, the damage caused by lightning disasters to the computer network system can be prevented and mitigated as much as possible.
5. Measures for Lightning Protection Since computer network equipment is generally placed in a computer room in a building, buildings often have lightning protection facilities against direct lightning strikes. Under normal circumstances, network equipment is protected from direct lightning strikes by lightning protection systems of buildings. In a non-exposed area of ​​lightning, the possibility of direct lightning strikes is relatively small, and the probability of experiencing lightning is higher. Therefore, the computer network system considers more of the protection issues of inductive lightning and lightning wave invasion.
1,
Lightning protection of power supply system According to the requirements of the National Standard of the People's Republic of China for "Lightning Protection Design for Buildings" (GB50057-94), in order to prevent the inductive power from intruding through the power line from damaging the equipment room information system, it is installed at the distribution box introduced by the power line. Overvoltage protection device. Main class lightning protection: Install high-capacity lightning arrester at the incoming line of the power distribution box of the engine room. When the lightning strike is triggered, the main lightning arrester can be quickly broken down, and the high voltage surge of the lightning strike can be discharged into the earth to protect it. Room equipment. Secondary lightning protection: In order to prevent lightning residual voltage from invading the equipment, installing a small-capacity lightning arrester or lightning protection socket at the incoming line of the equipment power line can further reduce the influence of inductive lightning and protect electronic equipment from damage.
2. The lightning protection signal of the signal system is installed at the input end of all kinds of signal lines and is used to protect the important equipment connected with the communication network, data network and computer network. All signal lightning protectors can use two-level protection technology combining non-radioactive three-level discharge tube and fast clamping diode, making:
Discharge capacity (non-destructive) in 8/20μS wave >5KA
Protection reaction time <1ns
Failure protection in case of a continuous fault Short-circuit function Thanks to the use of a three-electrode discharge tube, the three-pole simultaneous discharge characteristic guarantees effective protection even under poor grounding conditions. They can withstand continuous surge shock waves without damage, and they will be safely disconnected in the following cases:
A. Long-term continuous overvoltage B, abnormally strong lightning impact C, and lightning protection of data processing equipment, we considered two significant characteristics of the network, namely: extremely low operating voltage and high transmission frequency. The lightning protector is best for protection. When installing the signal lightning arrester, we should consider all system features:
A. Grounding of the lightning protector device: The protective device adopts the shortest possible path and is connected to the grounding network through a conductor having a sufficient cross section.
B. Grounding, shielding network: The electrical grounds of all equipment are connected to each other to limit the potential difference.
C. The relative position of the lightning arrester and the protected device: It is 3 meters away from the device or at the entrance of the device.
D. Connection of lightning arrester: Connect the incoming line (or cable) and the protected outgoing line (or device) in the specified direction; the shielding layer does not constitute a grounding network.
E. Add additional protection to the equipment power line:
For specific equipment protection, consider the number of wire pairs to be protected, the type of circuit and the level of protection, and the wiring method: Usually, there are several kinds of wire-wound, card-type, RJ11, RJ45, and screw-fastening.
3. The grounding system grounding system of the equipment room is a comprehensive information processing project involving many aspects. It is part of the lightning protection system and an important part of the computer room house construction. It not only affects the normal operation of the computer equipment itself, but also Is directly related to the safety of computer equipment and staff. Whether the grounding system is good or not is one of the key issues to measure the quality of a computer room construction. Generally, in the design of the equipment room, independent DC fields, communication work sites and lightning protection grounds, and distances between the DC ground and lightning protection grounds are used. Should be greater than 10 meters, the grounding resistance of the DC ground should be less than 2Ω, the grounding resistance of the AC working ground should be less than 4Ω and the grounding resistance of the lightning protection ground should be less than 10Ω.
The grounding system consists of a grounding wire and a grounding body. The grounding wire is the metal wire used to connect the grounding part of the electrical equipment and the grounding body. The grounding wire is the metal conductor set that directly contacts the ground.
The grounding wire adopts a flat iron or copper wire with a certain cross-sectional area, and a 3×20mm copper wire is often used in the design of a general system scheme.
Grounding will be independent of the lightning protection system, signal ground, inductive ground, and power ground are duplicated. Repeatedly consists of a grounding body, a grounding lead-in, a bus bar, and a grounding wire. Grounding body can be selected according to the actual situation of the level of laying, vertical piling two methods, and then adjust the size according to the soil conditions, change the soil and add a long-term resistance reducing agent (WJD01Z), so that the grounding resistance meets the requirements of less than 2 ohms.
The grounding body generally adopts 10*60MM copper plates, each about 2.5 meters long, and the top end is about 1 meter above the ground and under the permafrost: the top ends are all welded with copper plates to form a unified grounding system. The grounding lead and the copper plate are tight. Solid connection can be as shown:
Second, the engine room lightning protection principle:
Introduce most of the lightning current directly into underground leakage (external protection); Blocking overvoltage waves introduced along power lines or data lines, signal lines Harm the equipment (internal protection and overvoltage protection); Limit surge on protected equipment Voltage amplitude (overvoltage protection). The above three lines of defense are mutually compatible and each one of them is indispensable. When we are doing protection, we should make full use of the external protective facilities of the building itself and consider the protective elements in the equipment room. We only focus on the discussion of the inside of the equipment room. Protective elements.
Third, the type of lightning:
1.
Direct lightning strike lightning over-current directly hit the building where the device is located or device connection line and through the network equipment into the ground is called direct lightning, direct Lei Lei contains great energy, voltage peak up to 5000KV, with great destructive power, If a building is directly struck by lightning, huge lightning currents flow down the ground and cause the following three kinds of destructive effects:
A. A huge lightning current flows into the ground in a few microseconds, causing the ground potential to rise rapidly, causing a counterattack and endangering personal safety and equipment safety.
B. Lightning currents generate powerful electromagnetic waves, and extremely high pulse voltages are induced on the power lines and signal lines, thereby causing devastating damage to the settings.
C. Lightning currents flow through electrical equipment and generate extremely high heat, causing fire or explosion.
2.
Lightning strikes lightning strikes on the line or the extremely high voltage generated by electromagnetic induction is transmitted from the outdoor power line and communication line to the building, damaging the electrical equipment.
3.
Lightning induced by the lightning current electric current generated by the conductor over-voltage, over-current caused by the lightning strike is called inductive lightning, through the power line, signal feeder induced lightning voltage intrusion computer network system, high pulse voltage, peak up 50KV, resulting in a large area of ​​network system equipment damage.
Fourth, several ways of lightning damage to network equipment:
Lightning attacks on computer network systems mainly have the following three ways:
(1) Directly striking the lightning through the building's air-termination device (Franklin lightning rod, lightning protection zone) discharges the lightning current into the ground, resulting in tens of thousands of volts of ground network ground potential. The device ground wire invades the network equipment to form a ground potential counterattack.
(2) When a lightning current enters the ground along a lightning deflector of a building, a strong magnetic field is generated around the down conductor, and an overvoltage is induced on the metal pipe (line) around the down conductor. The power is transmitted through the network system. Or signal lines invade the network system.
(3) Power lines or communication lines that enter or leave the building, and lightning voltages and overcurrents that are loaded by direct lightning or induced lightning outside the building break into the line and infringe the network equipment.
It can be seen that thunder and lightning mainly invade computer network systems through power supply lines, communication lines and grounding systems. Therefore, the lightning protection of the network system is mainly aimed at the above-mentioned three possible lightning protections. By increasing the lightning protection facilities at all levels, the damage caused by lightning disasters to the computer network system can be prevented and mitigated as much as possible.
5. Measures for Lightning Protection Since computer network equipment is generally placed in a computer room in a building, buildings often have lightning protection facilities against direct lightning strikes. Under normal circumstances, network equipment is protected from direct lightning strikes by lightning protection systems of buildings. In a non-exposed area of ​​lightning, the possibility of direct lightning strikes is relatively small, and the probability of experiencing lightning is higher. Therefore, the computer network system considers more of the protection issues of inductive lightning and lightning wave invasion.
1,
Lightning protection of power supply system According to the requirements of the National Standard of the People's Republic of China for "Lightning Protection Design for Buildings" (GB50057-94), in order to prevent the inductive power from intruding through the power line from damaging the equipment room information system, it is installed at the distribution box introduced by the power line. Overvoltage protection device. Main class lightning protection: Install high-capacity lightning arrester at the incoming line of the power distribution box of the engine room. When the lightning strike is triggered, the main lightning arrester can be quickly broken down, and the high voltage surge of the lightning strike can be discharged into the earth to protect it. Room equipment. Secondary lightning protection: In order to prevent lightning residual voltage from invading the equipment, installing a small-capacity lightning arrester or lightning protection socket at the incoming line of the equipment power line can further reduce the influence of inductive lightning and protect electronic equipment from damage.
2. The lightning protection signal of the signal system is installed at the input end of all kinds of signal lines and is used to protect the important equipment connected with the communication network, data network and computer network. All signal lightning protectors can use two-level protection technology combining non-radioactive three-level discharge tube and fast clamping diode, making:
Discharge capacity (non-destructive) in 8/20μS wave >5KA
Protection reaction time <1ns
Failure protection in case of a continuous fault Short-circuit function Thanks to the use of a three-electrode discharge tube, the three-pole simultaneous discharge characteristic guarantees effective protection even under poor grounding conditions. They can withstand continuous surge shock waves without damage, and they will be safely disconnected in the following cases:
A. Long-term continuous overvoltage B, abnormally strong lightning impact C, and lightning protection of data processing equipment, we considered two significant characteristics of the network, namely: extremely low operating voltage and high transmission frequency. The lightning protector is best for protection. When installing the signal lightning arrester, we should consider all system features:
A. Grounding of the lightning protector device: The protective device adopts the shortest possible path and is connected to the grounding network through a conductor having a sufficient cross section.
B. Grounding, shielding network: The electrical grounds of all equipment are connected to each other to limit the potential difference.
C. The relative position of the lightning arrester and the protected device: It is 3 meters away from the device or at the entrance of the device.
D. Connection of lightning arrester: Connect the incoming line (or cable) and the protected outgoing line (or device) in the specified direction; the shielding layer does not constitute a grounding network.
E. Add additional protection to the equipment power line:
For specific equipment protection, consider the number of wire pairs to be protected, the type of circuit and the level of protection, and the wiring method: Usually, there are several kinds of wire-wound, card-type, RJ11, RJ45, and screw-fastening.
3. The grounding system grounding system of the equipment room is a comprehensive information processing project involving many aspects. It is part of the lightning protection system and an important part of the computer room house construction. It not only affects the normal operation of the computer equipment itself, but also Is directly related to the safety of computer equipment and staff. Whether the grounding system is good or not is one of the key issues to measure the quality of a computer room construction. Generally, in the design of the equipment room, independent DC fields, communication work sites and lightning protection grounds, and distances between the DC ground and lightning protection grounds are used. Should be greater than 10 meters, the grounding resistance of the DC ground should be less than 2Ω, the grounding resistance of the AC working ground should be less than 4Ω and the grounding resistance of the lightning protection ground should be less than 10Ω.
The grounding system consists of a grounding wire and a grounding body. The grounding wire is the metal wire used to connect the grounding part of the electrical equipment and the grounding body. The grounding wire is the metal conductor set that directly contacts the ground.
The grounding wire adopts a flat iron or copper wire with a certain cross-sectional area, and a 3×20mm copper wire is often used in the design of a general system scheme.
Grounding will be independent of the lightning protection system, signal ground, inductive ground, and power ground are duplicated. Repeatedly consists of a grounding body, a grounding lead-in, a bus bar, and a grounding wire. Grounding body can be selected according to the actual situation of the level of laying, vertical piling two methods, and then adjust the size according to the soil conditions, change the soil and add a long-term resistance reducing agent (WJD01Z), so that the grounding resistance meets the requirements of less than 2 ohms.
The grounding body generally adopts 10*60MM copper plates, each about 2.5 meters long, and the top end is about 1 meter above the ground and under the permafrost: the top ends are all welded with copper plates to form a unified grounding system. The grounding lead and the copper plate are tight. Solid connection can be as shown: