Electrical Equipment Anti-static Grounding System
In the process of enterprise network development, the core part of the computer room has always played a decisive role, and the construction of the computer room and its operating environment have long been widely concerned by experts and scholars.
In particular,many computer rooms have been damaged to varying degrees due to external interference (such as lightning, static electricity, over-current and over-voltage, etc.), causing network interruptions and stops.In severe cases, it will burn equipment and even cause casualties.
Such things have happened frequently in recent years, and the harm to the enterprise is obvious. Therefore, it is necessary to ensure that the equipment room has a good software and hardware environment, and it is necessary to ensure the normal operation of the equipment.
The grounding lightning protection technology of the electronic equipment room must emphasize the three principles of science, economy, practicality and durability.
The general grounding system contains two grounding grids:
Artificial grounding body
Grounding of the equipment room
The grounding wire (UPS chassis grounding wire) of all electronic equipment in the equipment room must be the total grounding of the equipment room ground wire to ensure the same potential of the electronic equipment.
A grounding grid is set up in the equipment room, and its grounding resistance is less than 2 ohms.
Each grounding portion of the electrical installation shall be connected to the grounding conductor with a separate grounding wire.Do not connect several grounding parts in a grounding wire.
An effective lightning protection system, including at least three aspects of external, internal and overvoltage protection. The correct connection and grounding are the key aspects of all aspects.
An important aspect of lightning protection engineering is the grounding and wiring of the down-conductor. The lightning protection effect of the entire project and even the lightning protection device are all dependent on this.The grounding system is the most difficult and important part of the construction of lightning protection engineering.There are also large differences in the design of the grounding grid due to the different environments.
In fact, the requirements for lightning protection grounding system is not so complicated compared the computer information system grounding. It is necessary to pay attention to two aspects:
The counterattack of lightning is usually the metal body that is subjected to direct lightning strikes(including the lightning receptor, grounding down conductor and grounding body),there is a high voltage between the flashing moment and the earth.The phenomenon that this voltage discharges (also called flashover) to other metal objects connected to the earth is called counterattack.To eliminate counterattacks, two measures are usually taken:One is to make an equipotential bonding, and the two metal conductors are connected by a metal conductor so that the potentials are equal when the flash is connected; the other is to maintain a certain distance between the them.
Protective measure of the inductive lightning
When the thundercloud occurs from the flash, the cloud flashes, and the cloud flashes,the lightning pulse generated by various types of metal pipes and lines entering the building plays a limiting role.Thereby protecting the safety of personnel and various electrical equipment in the building.
The measures taken should be based on the specific conditions of the various equipment,in addition to a good grounding and wiring system, safety distance, it is necessary to install the corresponding lightning arrester and take shielding measures according to the power supply line, power line, signal line, communication line, and feeder line.
The grounding wire and the down conductor of the lightning protection system are connected to a grounding trunk such as a lightning rod;Used to guide direct lightning strikes;In order to reduce lightning induction, all parts of the system must be outside the communication device 3M.The building base is generally used as a lightning protection ground.
The modern high-rise foundation is tied with large-area steel bars.The pillar main reinforcement and the surrounding walls pass straight to the roof daughter wall lightning protection belt.The grounding resistance value generally meets the requirements of GB50057-94, that is, less than or equal to 4 ohms.
Because the equipment room is directly connected to the lightning protection network,it takes impact:First, the network is susceptible to interference;Second, it is easy to be counterattacked by lightning.The ground potential is raised and stringed into the device to form a potential difference with other lines.The lightning protection grounding should be independently laid out separately from the machine room, and connected by the German OBO 480 type ground protector.
The grounding device consists of a grounding wire and a grounding body.The grounding wire is a metal wire for connecting the grounding portion of the electrical equipment to the grounding body;The grounding body is a group of metal conductors that are in direct contact with the earth.The grounding wire is made of flat iron or copper wire with a certain cross-sectional area.
It is composed of a grounding body, a grounding lead-in wire, a bus bar, and a grounding wire repeatedly. The grounding body can be selected according to local conditions, horizontal laying and vertical piling,then adjust the size according to the soil conditions, change the soil and add a long-term resistance reducer, so that the grounding resistance meets the standard of less than 2 ohms.
The grounding body is generally made of 60*60*2000 galvanized iron, with a pitch of about 5 meters vertically into the ground, and the top is about 0.7-0.8 meters from the ground,the top end is then welded with flat iron of about 40MM*4M or round steel of diameter 20 to form a unified grounding system, and the grounding lead is fastened to the flat iron.
In order to reduce the shielding effect of adjacent grounding bodies, the spacing of the vertical grounding bodies is not less than twice the length, and the spacing of the horizontal grounding bodies shall be not less than 5 meters according to the design regulations.
The distance between the grounding body and the building is preferably 3 meters.
The grounding system is implemented in strict accordance with the relevant regulations of the state.At the same time at the decoration, the user will be in the proper grounding location around the building.In the grounding construction phase, pay attention to the choice of grounding body and the choice of location, to ensure that the grounding resistance is less than 2 ohms (depending on the design and local climate conditions), and pay attention to the corrosion protection of the grounding body.