The introduction of mobile communication base station and the main way of lightning protection measures

Of: Li Yang, Yao Bin Qiu Zhu Wei Sri Liu Zigang

This paper analyzes the introduction of mobile communication base station of the main ways lightning, and on this basis, details of the mobile communication base station tower and the communications room lightning, lightning protection of overhead lines, Antenna lightning protection, grounding, bonding and reduce the resistance, etc. lightning protection measures to be mine Technology program development, reliable, economical and reasonable.

Keywords: communication base station; lightning; to introduce ways; protective measures


With the rapid development of the communications Industry, widely used in microelectronic devices, communications equipment, more integrated, and its getting lower and lower voltage levels [1]. Because the mobile communication base station and wide distribution, location in the high ground, vulnerable to lightning disasters [2]. lightning has a strong destructive, once the base stations being struck by lightning, likely to cause damage to communications equipment, communications, signal interruption, has brought greater economic impact, so do the anti-mobile communication base station Ray is an important work [3].

1 lightning the main way mobile communication station
1.1 Lightning Tower and Antenna through the invasion of the base station
The base station tower height generally 40 ~ 60 m, some as high as 70 ~ 90 m. When the tower was a direct lightning strike the lightning rod, the lightning current through the tower, the bulk of its grounding device into the ground, so to network ground potential rise, leading to the base station to network and equipment, the potential difference between the high ground back to form, damage to communications equipment. If the Antenna for the coaxial cable, the conductor induces a strong induced current, is the coaxial cable of the sensor current. induced current into the antenna via coaxial cable from the base station tower room, into the transceiver, burned mobile communication devices.

Penetrated through the overhead line lightning 1.2
Mobile communication system base station overhead lines is an important way for the introduction of mine-affected. When Thundercloud discharge, the space to create a strong electric field, in the overhead line near the terminal, the main ingredient is the level of the electric field, in prominent objects in the electric field in the most vulnerable induced charge appears concentrated around the electric field strength to a significant increase in overhead lines are prone to point discharge was struck by lightning. When the case of overhead line lightning attack, it will be over-voltage into the base station computer room, probably burn out the base station communication equipment . Thundercloud-to-ground discharge will also be over-voltage overhead line on the sensor, the over-voltage power supply will also pose a threat.

1.3 The impact of lightning electromagnetic induction
Air terminals in the next flash process, the lightning current intensity, the discharge time is short, and the deflectors in the air terminals around the fields will produce a larger transient. In a strong magnetic field, a conductor in a magnetic field will produce up to a few thousands to tens of thousands of volts of induced voltage, so high induced voltage potential may cause damage to communications equipment. mobile communication device is a high integrated device, the relatively poor impact resistance, so greatly influenced by the lightning sensor.

1.4 Base Station Rooms introduction of lightning
When the mobile base stations built in the top room, the room location of the high altitude, the cloud-to-be around the lightning struck from the horizontal and inclined to be protected, a phenomenon called LIGHTNING. In this case, isolated Defense often has been a lightning rod for lightning on the room can not be direct. Therefore, the base station must take the necessary room lightning protection measures.

2 Integrated Base Station Lightning Protection
2.1 Lightning Tower
Tower antenna platform at the top, middle and base of the tower at the tower should be reserved for ground holes, or use a nearby tower extended fastening bolts fastening bolt for ground. Because of the higher tower, the adjacent two connected distance of more than 60 m between locations, the need to increase the network between a ground point. we must ensure that the number of connection points and the dispersion of the lightning current to facilitate dispersion. tower tower for the landing, the tower room to network and ground network to be between 3 ~ 5 m intervals between welding connection 1, and at least two interconnected. tower legs and other places nearby welding network connectivity. Mobile communication antennas should be protected against cloud-to-measure. Antenna Tower and tower design and welding rod. antenna installation location should be in the lightning rod lightning protection zone. The purpose of welding rod and the tower is to ensure a good ground rod to ensure timely lightning current into the earth.

2.2 The overhead line lightning protection
Connected to the engine room of the power lines, fiber optic cable directly into the overhead lines can not be classified after penetration into the buried metal pipe room. If the distance is longer, the power lines, fiber optic cable shall be installed at both ends of protection. Metal tube with both ends ground wire welding, spot to be treated with preservatives, power lines and signal lines can not be mixed alignment. the system grounding should be in accordance with the installation requirements, respectively, each connected to ground bus, connected to the reunification of the indoor ground row. the engine room DC ground wire from the indoor ground into rafts, and protected independently, and then ground bus access, and does not share the lead.

Lightning 2.3 days feeder
Shield should be in the top feeder, feeder left corner of the tower to the room above the 0.5 ~ 1.0 m enter into the room after the inside of the 3 imported properly grounded. When the length exceeds 60 m, should increase the connection between the place in which, ground point of adjacent two less than the distance between the 60 m, indoor alignment rack should be grounded at intervals of 5 ~ 10 m 1. Some manufacturers require feeder into the room after the installation of surge arresters, surge arresters should be mounted as close to feeder into the entrance of a building.

Links to download free paper communications room of the mine http://www.hi138.com 2.4
Lightning Protection for the communications room of the building should include lightning protection and grounding the engine room, engine room equipment and lightning protection and grounding the power supply system. First, lightning protection and grounding of buildings. Telecommunication room-day faces regulatory requirements should be set up lightning network room corners should be set deflectors, the top metal machine housing facilities should be nearby and lightning are connected with welding. When the communication antenna tower located in the room next to the site, the tower room ground network to network and between the intervals should be between 3 ~ 5 m Welding connection 1, and at least two interconnected. When the communication site antenna tower located in the engine room roof, their legs should be on the roof and nearby lightning current deflectors are connected. buildings of metal window frames, cable shielding, equipment housing, should also be reinforced for reliable connection with the main form equipotential body [4-5]. Second, lightning and grounding the power supply system. equipotential communications ground terminal within the room should be used between plate bolts, the connecting wires cross-sectional area should be not less than 16 mm2 of the multi-strand copper wire, wearing a steel pipe laying. out of room in the cable metal sheath into the station should be protected at the ground, within the core wire cables should be installed in the pit at the arrester, cable the air line should be protected on the ground. engine room of the support rail should be ground every 5 m 1, the alignment rack, hanging iron, the rack (or cabinet), metal ventilation pipe, metal doors and windows and other metal pipes should be well grounded and connected with each other. communications room of the power supply and communication power transformers should not be room in the same building, if installed inside the communications room, the high-voltage power cable length should be not less than 200 m, with joint of overhead power lines, cables, nearby metal outer sheath should be grounded, the cable should be within the three-phase lines were installed on the ground zinc oxide surge arresters without gaps.

2.5 bonding
Mobile communication base stations to network should have pressure, such as potential theory, will work to protect the land and mine to form a joint ground network, base stations within the various types of ground wire or ground wire from ground pool line were introduced. For the high soil resistivity base stations in the mountain area network, in addition to resistance to reduce, the most important thing is for bonding, shielding, and are pressure treated to achieve the potential distribution between the various parts of uniform, so that potential difference of "zero "to ensure that all parts of the lightning current will not cause back pressure and reducing electromagnetic interference.

2.6 reduce the grounding resistance
National standard mobile base stations to the resistance should be less than 5 ��, at high soil resistivity areas, reduce the grounding resistance of the common methods are the following: First, extension of introduced multi-grounding devices, external lead length should not exceed the effective length; the second is the grounding of low resistivity buried in deep soil; third is the use of reduction agent; Fourth, soil replacement. Practice has proved that change is to improve soil soil thus reducing the grounding resistance of the best methods. The approach is: the smaller the resistivity powder with mineral mud, pond scum, Tian mud, soil, clay and other substances to the net replacing high resistivity soil.

3 References
[1] YD5098-2005 Communications Office (stations) for engineering design of lightning protection and grounding [S]. Beijing: Beijing University of Posts and Telecommunications Press, 2006.

[2] GB50343-2004 lightning protection Technology of building electronic Information system specification [S]. Beijing: China Building Industry Press, 2004.

[3] Yu Hao. Modern mine Technology base [M]. Beijing: Tsinghua University Press, 1995.

[4] Zhou Zhimin. Electronic Information System Lightning Protection Technology [M]. Beijing: People's Posts and Telecommunications Press, 2004.

[5] Zhang Xiaoqing. Building lightning protection and grounding Technology [M]. Beijing: China Electric Power Press, 2003.

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