Seek the relevant lightning protection specifications and lightning protection development history (including belt life, relevant institutions, testing institutions, appraisal institutions, etc.)

lightning protection refers to the protection technology to prevent the building itself or its internal equipment from being damaged by direct lightning or lightning electromagnetic pulse by forming an integrated system to intercept, dredge and finally release into the ground.

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History

Benjamin Franklin July 1752 Benjamin? Benjamin Franklin's famous kite experiment [1] (176-179) and the publication of lightning rod in 1753 revealed the history of human resistance to lightning. In 1873, Maxwell [2] (James Clerk Maxwell 1831-1879) published a scientific masterpiece, Electromagnetic Theory, which systematically, comprehensively and perfectly expounded the electromagnetic field theory. Later, with the application and popularization of electromagnetic theory, the protection against electromagnetic pulse was formally included in the lightning protection category. Direct lightning protection and electromagnetic pulse protection constitute the whole lightning electromagnetic pulse protection and are still in use today.

in China, the lightning protection industry and technology started late, and the first lightning protection enterprise was born in the late 198s. The first lightning protection technology forum held in Shenzhen in May 22 marked the formal maturity of the lightning protection industry in China. At the beginning of this century, China promulgated two general lightning protection standards, namely, GB 557-1994 Code for Lightning Protection Design of Buildings (revised in 2) and GB 5343.

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Lightning Protection System

Legend of lightning protection system(LPS) refers to a complete set of devices used to protect a certain space from lightning effects, which consists of an external lightning protection system and an internal lightning protection system.

note: under certain circumstances, the lightning protection system can only be composed of external lightning protection devices or internal lightning protection devices.

At present, lightning electromagnetic pulse protection technology, that is, lightning protection technology, has matured, and all major lightning protection enterprises in China can realize the lightning protection integrated system solution (lightning protection system) from design, product provision to construction and after-sales service. A complete lightning protection system is divided into the following five parts according to different functions:

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Direct lightning protection

Direct lightning protection is to prevent lightning from directly striking buildings, structures, electrical networks or electrical devices. Direct lightning protection technology is mainly to protect the building itself from lightning damage, and to reduce the impact on the internal space of the building during the process of huge lightning current leaking into the earth along the building during lightning strike, which is the first part of lightning protection system. Lightning protection and direct lightning protection technologies are mainly lightning rod, lightning belt, lightning net and lightning wire, among which lightning rod is the most common direct lightning protection device. When the Lei Yun discharge approaches the ground, it distorts the ground electric field, and forms a space with concentrated local electric field intensity at the top of the lightning rod, so as to influence the development direction of lightning pilot discharge, guide the lightning to discharge to the lightning rod, and then introduce lightning current into the ground through the grounding downlead and grounding device, thus preventing the protected object from being struck by lightning. The word "lightning protection" on the lightning rod only means that it can prevent the protected object from lightning damage, but on the contrary, it is "attracting lightning" to the upper body.

At present, the main lightning rods include conventional lightning rods, pre-discharge lightning rods, active optimization lightning rods, current-limiting lightning rods and typical lightning rods for prevention. The pre-discharge lightning rod WJZ series lightning rods produced by Henan Wanjia Lightning Protection Company, such as WJZ25-1C, are commonly used and famous in the world.

grounding

(earth; Ground)

an intentional or unintentional conductive connection, by which a circuit or electrical equipment can be connected to the ground or to a larger conductor instead of the ground. Note: The purpose of grounding is: (a) to make the conductor connected to the ground have the potential equal to or close to the earth (or the conductor replacing the earth); (b) Guide human-earth current to flow into and out of the earth (or a conductor instead of the earth).

by definition, grounding can be divided into: artificial grounding and natural grounding; From the nature of work, it can be divided into two categories: grounding protection (such as lightning protection grounding, anti-static grounding, equipment grounding, distribution point grounding, etc.) and working grounding (such as the grounding of power facilities, transmission and distribution, and the logical grounding of electronic circuits that do not need actual physical connection in working grounding).

the grounding system achieves the protection purpose by balancing the factors including resistance, structure and mutual coordination, and releasing the threats caused by direct lightning strike, lightning electromagnetic pulse, static electricity accumulated on equipment, short circuit of power system and other abnormal energy.

At present, the common grounding systems mainly include copper-clad steel grounding system, long-term high-conductivity active ion grounding system, etc., and the common hot-melt welding construction technology is used in the connection process between grounding unit and emperor.

equipotential bonding

equipotential bonding refers to connecting separated devices and conductive objects with equipotential bonding conductors or surge protectors to reduce the potential difference between them caused by lightning current.

The principle of equipotential bonding is that the grounding systems which are independent of each other under normal conditions are automatically connected with the potential difference between the systems through equipotential connectors, thus forming a larger common earthing system and releasing abnormal energy more effectively.

electromagnetic shielding

electromagnetic shielding is a shielding that uses conductive materials to reduce the penetration of alternating electromagnetic fields into designated areas. The lightning electromagnetic pulse propagates around the lightning strike point, and its influence range can reach 2 kilometers or even more, and it is not limited to the building itself or the lightning protection engineering flow chart in it.

Electromagnetic shielding technology mainly includes two parts: empty point electromagnetic shielding technology and line electromagnetic shielding technology.

Space electromagnetic shielding technology is to block the invasion of electromagnetic waves through metal material layers with reliable and continuous electrical connection distributed in all directions, and to convert electromagnetic energy into electrical energy through energy conversion on the shield, and then to discharge it into the ground through grounding devices.

the electromagnetic shielding technology of lines is to lay through metal pipes (slots) and reliably ground both ends of continuous metal pipes (slots) to form a shield to prevent the electromagnetic induction of electromagnetic pulses on metal lines from generating overvoltage. In addition to the space shielding function, the electromagnetic shielding technology of lines also has the function of generating back electromotive force to offset the overvoltage of lines when overvoltage is introduced.

overvoltage protection

overvoltage protection refers to a kind of protection applied by the power supply device and the connected equipment to prevent the power supply failure from generating excessive output voltage (including open circuit voltage).

overvoltage protection actually involves overvoltage protection of various systems, among which the most important ones are overvoltage protection of power supply system and overvoltage protection of communication system.

overvoltage protection technology is mainly to distribute electric energy to all electrical equipment in the system by using related equipment, which has reduced the maximum energy to the maximum extent, and then to achieve the functions of energy release and low residual voltage protection through multi-level protection of safety protection equipment for all electrical equipment. In practical application, considering the particularity of various systems, it is necessary to design special overvoltage protection schemes for different systems, which has achieved the protection purpose.

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Methods

Self-safety protection

1. When there is a gap of about one minute between two lightning strikes, try to hide in a place where you can protect yourself. Do not have the above lightning protection engineering flow chart conditions, you should immediately kneel down, bend forward, and put your arms around your knees.

2. In the wild, you can also rely on tall trees for lightning protection, but remember to stay at least two meters away from trunks and leaves. By analogy, it is not suitable to stay under isolated chimneys, beside tall metal objects and under telephone poles. Besides, it is not safe to stand under the eaves, so it is better to enter the building at once.

3. If you hold metal umbrellas, golf clubs, axes, etc. in a thunderstorm, you must throw them away or make them lower than your body. There are also some so-called insulators, such as hoes, which are not insulated in thunderstorm weather.

4. During a thunderstorm, avoid standing under the lamp cap line when turning on the light indoors.

5. It is not advisable to use a shower. Because the water pipe is connected with lightning protection grounding, lightning current can be conducted by water flow, causing casualties.

protection of household appliances

1. If possible, power surge arresters should be installed at the power supply entrance, and signal surge arresters should be installed at the cable TV antenna, telephone, fax machine, computer MODEN modem entrance and satellite TV cable interface. But when installing, you should have a good grounding wire and make a good grounding network at the same time.

2. Listen to the weather forecast every day. When you know that there is a thunderstorm that day, you should unplug the power plug and signal plug of household appliances before going to work, and don't forget to close the doors and windows when you go out to prevent the intrusion of rolling thunder.

protection of buildings

1. lightning protection nets (belts) or lightning rods installed on buildings or lightning receptors composed of them should be adopted. Lightning protection network (belt) shall be laid along the corners, roofs, eaves and cornices vulnerable to lightning according to the provisions in Appendix 2 of this specification, and a grid of not more than 1m×1m or 12m×8m (the grid density shall be determined according to the building category) shall be formed on the whole roof. All lightning rods shall be connected with each other by lightning strips.

2. There should be at least two down leads, which should be evenly or symmetrically arranged around the building, and the spacing should not be greater than 18m (the spacing of down leads should be determined according to the building category). When only the steel columns or column reinforcement around the building are used as the down lead, the down lead can be set according to the span, but the average spacing of the down lead should not be greater than 18m.

3. The impulse grounding resistance of each down conductor should not be greater than 1Ω. The grounding device for lightning protection should be the same as the grounding device for lightning induction protection, electrical equipment and information system, and should be connected with buried metal pipes; When they are not used or connected, the distance between them in the ground should meet the requirements of the following expression, but it should not be less than 2m:

In the case that * * * is connected to the buried metal pipeline by grounding device, the grounding device should be laid into a ring grounding body around the building.

see the following specifications for details.

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specification

GB 15599-1995 lightning safety specification for petroleum and petroleum facilities [3]

GB 557-1994 lightning protection design specification for buildings (with provisions) (2 edition) [4]

GB 5343-24 lightning protection technical specification for building electronic information systems (GB 5343-24) T21431-28 Technical specification for detection of lightning protection devices in buildings

GBJ 79-1985 Code for design of communication grounding in industrial enterprises

GA 267-2 Code for lightning electromagnetic pulse safety protection of computer information systems

JR/ T26-26 Technical specification for lightning protection of banking computer information system

QX2-2 Technical specification for lightning protection of new generation weather radar stations

QX3-24 Technical specification for lightning protection of automatic weather stations

QX3-2 Technical specification for lightning electromagnetic pulse protection of meteorological information systems

QX4-2 Technical specification for lightning protection of meteorological stations < Code for design of lightning protection and grounding of 93 microwave stations (with provisions)

YD568-1998 Code for design of lightning protection and grounding of mobile data communication base stations

YD/T598-21 Code for design of lightning overvoltage protection engineering of communication offices (stations)

GA 173-22 Lightning protection device for computer information system

QX 1[1] .1-22 _ Surge protector Part 1: Performance requirements and test methods

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Relevant standards

IEC 6235-1-26 Lightning protection

IEC/TR 614-24-22 Wind turbine generator system. Part 24: lightning protection device iec 614-24

iec 6364-5-54-22 electrical facilities of buildings. Part 5-54: Selection and installation of electrical equipment. Grounding measures, Protective conductor and protective jumper iec 6364-5-54

iec 699 lightning arrester

GB 15599-1995 lightning safety code for petroleum and petroleum facilities

GB 557-1994 lightning protection design code for buildings (with provisions) (2 edition)

GB 5343-24 building electronics. P>GB/ t19271-23 lightning electromagnetic pulse protection

GB/t19663-25 lightning electromagnetic pulse protection

GB/t19663-25 information system lightning protection terminology

GB/t19856-25 lightning protection

GB/t214335. T21714-28 Lightning protection

GB/ T29.12-28 Electrotechnical terminology: lightning arrester, low-voltage surge protector and components

GB/ T745-1987 lightning protection guidelines for electronic equipment

GJB 58-24 lightning protection design and use requirements for military communication facilities

GJB 121-1991 implementation of grounding lap and shielding design

GJB 2269-1996 lightning protection technical requirements for rear ammunition warehouses

lightning protection product certification and product testing institutions:

1, The lightning protection devices in this paragraph

edited by Beijing Lightning Protection Device Testing Center

2, Shanghai Lightning Protection Device Testing Center

3 and china academy of railway sciences Communication and Signal Research Institute

can be roughly divided into: power lightning protection device, power lightning protection device socket, antenna feeder protector, signal lightning protection device, lightning protection testing tool, lightning protection device of measurement and control system and earth electrode protector. A complete lightning protection device includes lightning receptor, down conductor and grounding device. The above-mentioned needles, wires, nets and belts are just lightning arresters, and lightning arrester is a special lightning protection device. The sum of lightning arrester, down conductor, grounding device, surge protector and other connecting conductors.

lightning arrester

Lightning arrester, lightning conductor, lightning net and lightning belt are all lightning arresters. They all use their prominent position above the protected object to lead the lightning to themselves, and then drain the lightning current into the earth through down conductor and grounding device, so as to protect the protected object from lightning strike. The materials used for the lightning arrester should meet the requirements of mechanical strength and corrosion resistance, and should also have sufficient thermal stability to withstand the thermal damage of lightning current.