Exotic wood imports HS code references

List of the contents of this article:

• 1,Exotic wood imports HS code references How does the fire protection system do lightning protection?
• 2, Building Lightning protection system (I)
• 3, Analysis of lightning protection design scheme of communication base station system: lightning protection of base station
• 4, Lightning protection Schematic diagram of grounding system
• 5, I want to know about the lightning protection of the monitoring system? Tell me if you know anything.

How does the fire protection system do lightning protection?

1. The general principle is that all kinds of lightning protection buildings should take measures to prevent direct lightning strikes and lightning waves from invading people. Buildings equipped with lightning protection devices shall adopt isopotential connection when the lightning protection device cannot be isolated from other facilities and personnel in the building.

2. Especially in bad thunderstorms, ensuring the normal operation of the equipment of the fire center and not receiving the impact of some secondary disasters such as surges can life be guaranteed.

3. The large current shock caused the motherboard to burn out. Your situation has been reported by some customers.The grounding and lightning protection are not very good. A surge protector can be installed, which can play a protective role.

4. Fire broadcasting system lightning protection design: Fire broadcasting system, as one of the most important systems in recent days, its operation directly affects the safety of people's lives and property. Therefore, we have the obligation to strengthen the design and installation of its lightning protection facilities to ensure that they can be safe during the thunderstorm season. Run regularly.

5. The lightning rod cannot be connected to the water tank and water pipe. The top and bottom of the metal objects and metal pipes laid vertically in the lightning protection building should be connected to the lightning protection device. Pay attention to protect the non-metallic pipes that emit flammable and explosive gases on the roof, and include them in the protection scope of the flasher.

ConstructionLightning protection system (I)

1. The lightning protection system is mainly composed of lightning arrester (lightning rod, lightning protection belt, lightning protection line and lightning protection net), lead line and grounding device. The lightning resistance level of a building refers to the current value (unit Ka) when the lightning protection system of the building is subjected to the impact of lightning current without damage.

2. In addition, the grounding to prevent the harm of lightning is called lightning protection grounding; the grounding of electrical equipment, etc. to prevent the possible accumulation of static charge is called anti-static grounding; the grounding to achieve the effect of shielding is called shielding grounding or isolated grounding.

3. The lightning protection grounding system of the internal and external lightning protection grounding device building shall be composed of internal lightning protection grounding device and external lightning protection grounding device. The basis for the utilization of natural groundingThe horizontal rebar of the bottom plate is connected to form a grounding net, which is connected to the steel bars around the groove edge to form a closed loop, forming a natural grounding body.

4. General civil buildings such as residences and office buildings with an estimated number of lightning strikes greater than 0.3 times/a. ( 3) Third-level lightning protection 1) Buildings and provincial archives protected by provincial key cultural relics.

5. First-level lightning protection: When the building itself is equipped with a lightning protection system (such as lightning rod, lead line, ground network and external shielding), according to the relevant theories of IEC and VDE, lightning arrester (box) needs to be used at the 380/230V low-voltage distribution circuit inside the building. To establish potential connections such as lightning protection on the power line.

6. Characteristics of lightning: the lightning current discharge current is large, and the amplitude is as high as tens to hundreds of thousands of ampetes;The discharge time is extremely short, only about 50~100μs; the wavehead steepness is high, up to 50ka/s, which is a high-frequency shock wave. The voltage generated by lightning induction can be as high as 300~500kv.

Brief analysis of the lightning protection design scheme of communication base station system: base station lightning protection

The lightning protection work of communication base station is a comprehensive and highly systematic lightning protection project. The lightning protection design of communication base station system is mainly It is a comprehensive consideration from the aspects of the constituent characteristics of the base station, the geographical environment, the engineering interface of the system equipment, etc. The main components of the communication base station are power supply facilities, communication signal transmission and base station system equipment.

The maintenance experience of several years tells us that it must be based onThe actual situation of each base station is to design the lightning protection grounding system of the mobile communication base station, and implement the targeted lightning protection of the base station.

This lightning protection design scheme has a general guiding role, and it should be specially designed for special occasions according to the specific situation. Lightning protection design Anti-direct lightning design According to the characteristics of the location of the paging communication base station, the new paging communication base station should be strictly in accordance with the requirements of the second category of building protection in the Building Lightning Protection Design Specification GB50057-94.

Schematic diagram of lightning protection grounding system

1. The principle refers to preventing electromagnetic pulses of direct lightning or lightning from causing the building itself or its internal equipment by forming an integrated system of interception, dredging and finally discharge into the ground. Protection technology for damage.

2. First, look at the description, then look at the position of the line installation marked in the figure, and then check whether there is a lead line at the position of each column or shear wall.

3. The lightning protection grounding principle of the tower crane is to use grounding conductors to connect the lightning protection equipment to the earth to form a stable and reliable conductive channel, so that the lightning current can flow into the ground as soon as possible, so as to reduce lightning damage and protect the tower crane and construction site.

I want to know about the lightning protection of the monitoring system? Tell me if you know anything.

Because the economic conditions of each industry and even each unit are different and the security levels of monitoring needs are different, the integration of lightning protection equipment varies depending on the situation. Usually, the following lightning protection factors need to be considered: lightning protection of the transmission line and the transmission line of the transmission system are mainly the power line of the transmission signal line. .

The transmission cable of the monitoring system should be used to prevent the intrusion of lightning waves, and cables with shielding effect should be adopted, or the whole process should be laid with metal tubes. The shielding layer should be electrically connected, and the first and tail ends should be grounded or connected to equal potentials respectively. The part of the (LPZOA) area should be buried in the ground.

In thunderstorm weather, how can security monitoring equipment take lightning protection measures? Weak electric bright son shares 3 points.

Lightning protection of front-end equipment: There are two distribution methods of front-end equipment: outdoor and indoor. The indoor distribution generally will not be directly struck by lightning, but it is necessary to consider preventing lightning and overvoltage from infringing the equipment, while outdoor equipment also needs to prevent direct lightning strikes.

First, the power supply is lightning protection. Install an anti-surge protector on the power supply line to guide the lightning surge current through the ground wire.Entering the ground network, the power supply lightning protection is divided into first-level lightning protection, second-level lightning protection, and third-level lightning protection, and absorbs lightning surges step by step.

If it is difficult for the cable to penetrate the metal pipe in the whole process, it can be introduced through the metal pipe before the cable enters the terminal and front-end equipment, but the buried length shall not be less than 15 meters. At the entry end, the metal outer skin and steel pipe of the cable are connected to the lightning protection grounding device.