Several problems that should be paid attention to in lightning protection of small coal mines
1. This Atlas is the consolidation and confluence of the local revised version of 99D501-1, 99(03)D501-1, and 99(07)D501-1 of "Installation of Lightning Protection Facilities for Buildings".
2 Contents of Partially Modified Version of 99(03)D501-1 "Installation of Lightning Protection Facilities for Buildings":
2.1 Partially modified version 99(03)D501-1 of "Installation of Lightning Protection Facilities for Buildings" implements the Document No. 212 of the Ministry of Construction of the People's Republic of China (2002) and will review the Atlas 99D501-1 in accordance with the provisions of the new version of the structural specification. The provisions of the new version of the specification have been revised.
Talking about the lightning protection and design of the expressway monitoring system, with the gradual expansion of the highway network, the role of the monitoring system has become increasingly prominent. Because the front-end equipment and transmission lines of the expressway monitoring system are installed and laid along the expressway, the expressways are mostly away from the urban areas and surrounded by open spaces. This results in the system being vulnerable to lightning strikes and affecting the normal operation of the control system. Therefore, strengthening the lightning protection of the monitoring system is particularly important in the construction of the motor system for superhighway monitoring. First, the lightning damage to the monitoring system and ways of destruction Lightning damage to the monitoring system has the following main ways: 1. Direct lightning. The thunder and lightning strike directly on the open field external equipment to cause its damage; The thunder and lightning strike directly on the Wire and cause the wire to blow. 2. Lightning wave intrusion. When the system's power lines, signal transmissions, or metal pipes entering the monitoring room are struck by lightning or induced by lightning, lightning waves invade the equipment along these metal wires, causing a potential difference to damage the equipment. 3. Lightning induction. When a lightning strikes a lightning rod, a strong transient electromagnetic field is generated around the deflector. The monitoring equipment and transmission lines in the electromagnetic field will induce a large electromotive force. This phenomenon is called electromagnetic induction. When a charged lightning cloud emerges, the charge opposite to the thundercloud will be induced on the buildings and transmission lines under the cloud. This phenomenon is called electrostatic induction. Electromagnetic induction and electrostatic induction are collectively referred to as induction mines, also known as secondary mines, and they are much more likely to occur than direct lightning strikes. Second, the monitoring system lightning protection measures Highway monitoring systems are generally composed of field equipment, transmission cables, monitoring center equipment. The protective measures of the monitoring system mainly include: 1. Lightning protection of the front-end equipment. The front-end equipment mainly includes surveillance cameras, meteorological detectors, vehicle detectors, and road environment detectors. Their protection is mainly used for lightning protection (lightning rod or other lightning conductor) protection. For|Examination|Large|To prevent lightning wave intrusion into the front-end equipment along the line, an appropriate arrester should be installed on each line in front of the equipment, such as power line (220V or DC12V), video line, signal line and PTZ control line. For other equipment such as vehicle detectors without racks and low height equipment, corresponding lightning arresters and grounding lines should be installed on each line. 2. Lightning protection of transmission lines. Monitoring system transmission lines include communication cables, optical cables and power cables. The lightning protection of transmission lines is mainly protected by metal shielding. Basically, special pipelines are built along the expressway, and most of the cables are laid by pipes. The part without pipes is buried directly. For direct burial and pipeline laying, the transmission line is usually laid with a shielded cable or cable through the buried steel pipe, using a variety of metal shields to block and attenuate electromagnetic interference and overvoltage energy added to computers and other equipment. For bellows or plastic pipes, the buried steel pipe can be protected before the cable enters the terminal and the front-end equipment. The length of the buried pipe is not less than 15 meters. The metal jacket of the cable and the steel pipe are connected to the lightning protection grounding device at the terminal. 3. Monitoring center lightning protection. The monitoring center is mainly composed of computer systems, video wall systems, and video switching systems. In the monitoring system, the lightning protection of the monitoring room is the most important and should be carried out in various ways from direct lightning protection, lightning wave intrusion, equipotential bonding and surge protection. The building where the monitoring room is located shall have lightning rods, lightning protection strips or lightning protection nets that prevent direct lightning strikes. Various metal pipelines entering the monitoring room shall be connected to grounding devices for lightning protection. When the overhead cable is directly introduced, an arrester shall be installed at the entrance to the house, and the cable outer sheath and the self-supporting steel cable shall be connected to the grounding device. An equipotential bonding bus (or metal plate) shall be provided in the monitoring room. The equipotential bonding bus shall be connected to the lightning protection ground of the building to prevent the potential difference. Grounding of various surge protectors (arresters) | Exams | Large | Wires should be electrically connected to the equipotential connection busbars at the straightest and shortest distances. In the video transmission line, signal control line, intruder alarm signal line before entering the front-end equipment or before entering the center console should be equipped with a corresponding lightning protection device. 4. Grounding system. The grounding system mainly refers to the ground wire of the field equipment and the joint grounding network of the monitoring center. Generally, the depth at the end of the line is not less than 700mm, the vertical grounding body adopts 5×50×2500 galvanized angle steel, the horizontal grounding body adopts 4×40 hot galvanized flat steel, and the connection between the vertical grounding body and the horizontal grounding body adopts double-sided welding. The horizontal grounding body and the horizontal grounding body are welded on both sides. The welding length is not less than 10cm. The welding place is brushed with red lead or asphalt oil for antiseptic treatment. 4×40 hot dip galvanized flat steel is used for the ground wire, and grounding test points are reserved. Junctions with specifications of flat copper, flat copper flat steel joints using gas welding, on the flat copper reserve Ф 8 of the connection hole not less than three, with the corresponding specifications of stainless steel screws or copper screws. In addition, based on experience, it is recommended that the lightning protection ground wire should not be too long. When the lightning protection ground wire exceeds 30 meters, the lightning protection effect is only 50%. If the ground wire exceeds 50 meters, the lightning protection effect is almost zero, and the adjacent There should be no more than 20 meters between the two sets of grids and a common network should be used. When a single device uses a dedicated grounding device, its grounding resistance must not exceed 4Ω. When the system uses an integrated grounding grid, its grounding resistance must not exceed 1 Ω. In general, most monitoring centers use integrated grounding. In short, lightning protection is a systematic and complex issue. In the design of expressway monitoring systems, not only must the inspection of the geographic environment of the system be performed, but also the laying of cables, shielding, grounding networks, etc. In terms of design, we finally made reasonable choices for all kinds of arresters in order to receive good results.
1. This Atlas is the consolidation and confluence of the local revised version of 99D501-1, 99(03)D501-1, and 99(07)D501-1 of "Installation of Lightning Protection Facilities for Buildings".
2 Contents of Partially Modified Version of 99(03)D501-1 "Installation of Lightning Protection Facilities for Buildings":
2.1 Partially modified version 99(03)D501-1 of "Installation of Lightning Protection Facilities for Buildings" implements the Document No. 212 of the Ministry of Construction of the People's Republic of China (2002) and will review the Atlas 99D501-1 in accordance with the provisions of the new version of the structural specification. The provisions of the new version of the specification have been revised.
Talking about the lightning protection and design of the expressway monitoring system, with the gradual expansion of the highway network, the role of the monitoring system has become increasingly prominent. Because the front-end equipment and transmission lines of the expressway monitoring system are installed and laid along the expressway, the expressways are mostly away from the urban areas and surrounded by open spaces. This results in the system being vulnerable to lightning strikes and affecting the normal operation of the control system. Therefore, strengthening the lightning protection of the monitoring system is particularly important in the construction of the motor system for superhighway monitoring. First, the lightning damage to the monitoring system and ways of destruction Lightning damage to the monitoring system has the following main ways: 1. Direct lightning. The thunder and lightning strike directly on the open field external equipment to cause its damage; The thunder and lightning strike directly on the Wire and cause the wire to blow. 2. Lightning wave intrusion. When the system's power lines, signal transmissions, or metal pipes entering the monitoring room are struck by lightning or induced by lightning, lightning waves invade the equipment along these metal wires, causing a potential difference to damage the equipment. 3. Lightning induction. When a lightning strikes a lightning rod, a strong transient electromagnetic field is generated around the deflector. The monitoring equipment and transmission lines in the electromagnetic field will induce a large electromotive force. This phenomenon is called electromagnetic induction. When a charged lightning cloud emerges, the charge opposite to the thundercloud will be induced on the buildings and transmission lines under the cloud. This phenomenon is called electrostatic induction. Electromagnetic induction and electrostatic induction are collectively referred to as induction mines, also known as secondary mines, and they are much more likely to occur than direct lightning strikes. Second, the monitoring system lightning protection measures Highway monitoring systems are generally composed of field equipment, transmission cables, monitoring center equipment. The protective measures of the monitoring system mainly include: 1. Lightning protection of the front-end equipment. The front-end equipment mainly includes surveillance cameras, meteorological detectors, vehicle detectors, and road environment detectors. Their protection is mainly used for lightning protection (lightning rod or other lightning conductor) protection. For|Examination|Large|To prevent lightning wave intrusion into the front-end equipment along the line, an appropriate arrester should be installed on each line in front of the equipment, such as power line (220V or DC12V), video line, signal line and PTZ control line. For other equipment such as vehicle detectors without racks and low height equipment, corresponding lightning arresters and grounding lines should be installed on each line. 2. Lightning protection of transmission lines. Monitoring system transmission lines include communication cables, optical cables and power cables. The lightning protection of transmission lines is mainly protected by metal shielding. Basically, special pipelines are built along the expressway, and most of the cables are laid by pipes. The part without pipes is buried directly. For direct burial and pipeline laying, the transmission line is usually laid with a shielded cable or cable through the buried steel pipe, using a variety of metal shields to block and attenuate electromagnetic interference and overvoltage energy added to computers and other equipment. For bellows or plastic pipes, the buried steel pipe can be protected before the cable enters the terminal and the front-end equipment. The length of the buried pipe is not less than 15 meters. The metal jacket of the cable and the steel pipe are connected to the lightning protection grounding device at the terminal. 3. Monitoring center lightning protection. The monitoring center is mainly composed of computer systems, video wall systems, and video switching systems. In the monitoring system, the lightning protection of the monitoring room is the most important and should be carried out in various ways from direct lightning protection, lightning wave intrusion, equipotential bonding and surge protection. The building where the monitoring room is located shall have lightning rods, lightning protection strips or lightning protection nets that prevent direct lightning strikes. Various metal pipelines entering the monitoring room shall be connected to grounding devices for lightning protection. When the overhead cable is directly introduced, an arrester shall be installed at the entrance to the house, and the cable outer sheath and the self-supporting steel cable shall be connected to the grounding device. An equipotential bonding bus (or metal plate) shall be provided in the monitoring room. The equipotential bonding bus shall be connected to the lightning protection ground of the building to prevent the potential difference. Grounding of various surge protectors (arresters) | Exams | Large | Wires should be electrically connected to the equipotential connection busbars at the straightest and shortest distances. In the video transmission line, signal control line, intruder alarm signal line before entering the front-end equipment or before entering the center console should be equipped with a corresponding lightning protection device. 4. Grounding system. The grounding system mainly refers to the ground wire of the field equipment and the joint grounding network of the monitoring center. Generally, the depth at the end of the line is not less than 700mm, the vertical grounding body adopts 5×50×2500 galvanized angle steel, the horizontal grounding body adopts 4×40 hot galvanized flat steel, and the connection between the vertical grounding body and the horizontal grounding body adopts double-sided welding. The horizontal grounding body and the horizontal grounding body are welded on both sides. The welding length is not less than 10cm. The welding place is brushed with red lead or asphalt oil for antiseptic treatment. 4×40 hot dip galvanized flat steel is used for the ground wire, and grounding test points are reserved. Junctions with specifications of flat copper, flat copper flat steel joints using gas welding, on the flat copper reserve Ф 8 of the connection hole not less than three, with the corresponding specifications of stainless steel screws or copper screws. In addition, based on experience, it is recommended that the lightning protection ground wire should not be too long. When the lightning protection ground wire exceeds 30 meters, the lightning protection effect is only 50%. If the ground wire exceeds 50 meters, the lightning protection effect is almost zero, and the adjacent There should be no more than 20 meters between the two sets of grids and a common network should be used. When a single device uses a dedicated grounding device, its grounding resistance must not exceed 4Ω. When the system uses an integrated grounding grid, its grounding resistance must not exceed 1 Ω. In general, most monitoring centers use integrated grounding. In short, lightning protection is a systematic and complex issue. In the design of expressway monitoring systems, not only must the inspection of the geographic environment of the system be performed, but also the laying of cables, shielding, grounding networks, etc. In terms of design, we finally made reasonable choices for all kinds of arresters in order to receive good results.
T Post/Y Post can be installed with the panels without clamps and bolts, with easier installation and wider application.
T Post specification:
type: America standard with plate, Europe standard without plate
size: 0.95lb/ft, 1.25lb/ft, 1.33lb/ft
length: 5'-8'
surface treatment: hot dip galvanized or paint green normal
Y post specification:
standard size: 30*30*3mm, 35*35*3.5mm
weight: 1.32kg/m, 1.46kg/m, 1.83kg/m, 1.98kg/m, 2.05kg/m, 2.45kg/m
height: 1000mm, 1200mm, 1500mm, 1750mm, 2000mm, 2200mm, 2400mm
Surface treatment: galvanized and paint coated common color: black
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