1, General Provisions
1, communication system lightning over-voltage electronic devices and electromagnetic interference protection, the protection of communication lines, equipment and personal security of an important means to ensure that communication lines, equipment operation indispensable technical aspects.
2, the program design based on:
IEC1312 "Lightning electromagnetic pulse protection,"
GB50057-2000 "Building Lightning Protection Design Code",
VDE0675 "over-voltage protection devices,"
GA173-1998 "Lightning Protection of Computer Information System Security device"
GB-50174-93 "Engine Room mine design specifications,"
GB2887-89 "computer site technical conditions" and so on.
2, lightning-wave invasion of computer networks possible ways:
1, lightning hit a computer network directly to the physical line
a. lightning point of high voltage side power supply, lightning penetrated along the supply line to the power supply part of the computer network system, resulting in over-current and over-voltage caused by the network of the UPS power supply system damage, power outages, resulting in paralysis of the entire system.
b. Lightning Zhi Ji network wireless communications antennas along the antenna and feeding into the computer network system, resulting in communication interface, receiving systems, indoor units, routers and other networking major communications equipment damage.
c. lightning network communication cable lines (such as cable, DDN, Frame Relay, X25 line, telephone lines), producing a powerful mechanical force, violent shock waves, intense heat so that communication lines damaged; over-voltage over-current along the communication cable lines intrusion to the network system, resulting in routers, switches and front-end damage to the equipment.
2, sensor over-voltage
a. Over-voltage sensing circuit
As the network system in a building a large number of laid a variety of conductor lines (such as power lines, data communication lines, Antenna), these lines, the network structure and layout complexity of the building in different spatial locations within the heart of many circuits, when the building or near the region struck by lightning when the lightning discharge will be generated in the building interior space transient magnetic field pulse, this fast-changing magnetic fields cross-linking of these loops, will be in the loop sensors out of transient over-voltage circuit is connected with this threatening The electronic equipment.
b. Over-voltage sensing circuit
Network communication lines with sensory over-voltage sub-electrostatic induction and electromagnetic induction:
Electrostatic induction mainly refers to the overhead line is located near the lightning from the pilot channel is full of Thundercloud group charge on the overhead line has the role of electrostatic induction accumulation of a large number of opposite charge, when the Thundercloud main discharge started Leiyun in charge quickly and in, so that overhead line was originally bound the charge and promptly released, the formation of transient over-voltage waves. This wave close to the speed of light to the overhead lines on both sides of the spread of invasive lines connected at both ends of the network device be damaged.
When a direct lightning strike lightning in the lightning rod belt, because lightning current amplitude of large, steep waves head high, in the channel near the lightning current to generate a strong transient magnetic field. This powerful magnetic field will be directly in the power cord or network out of communication lines with sensory over-voltage, or intrusion into the network system, the damage to network devices. High-intensity (30KA Lei current) lightning discharge can be within 1km from the lightning strike point of impact on network systems, or even cause the system equipment damage. According to statistics, this sensor the computer lightning lightning accidents accounted for 70% of accidents.
c. Over-voltage coupling and the transfer of
Caused by lightning or high voltage transient over-voltage lines can often be coupled through the network or transfer homes to a network device, causing damage to the equipment.
3, lightning ground elevation invasion
Buildings suffered a direct lightning strike, the lightning current along the lightning protection system of the building and the grounding of all Yin Xiaxian network devices and the insulation distance is not enough equipment and lightning protection system is not common ground, will be a high voltage between the two and the discharge breakdown will occur, resulting in severe damage to network equipment, and even personal safety.
4, anti-jamming capability analysis of computer network equipment,
Because computers and network equipment from a large number of large scale integrated circuits, whose anti-jamming capability is weak, as though taken a number of anti-interference measures, more effective low-energy interference, but the lightning-generated electromagnetic pulse over-voltage over-current technology relatively weak, right surges or particularly sensitive to electromagnetic pulse mine, only to be passed by a dozen-volt power systems, data transmission lines and other means to destroy the computer's motherboard, RS-232 port, multi-function cards, network devices.
Third, analysis of lightning disturbance
1, power grounding flawed. The ground floor computer room is laid to the seventh floor of the computer room, as a computer, a separate ground. Ground too long, the lightning would not achieve the role of a good Discharge.
2, switch machines are electronic equipment, anti-jamming capability is weak. When the lightning struck the roof of the lightning belt, lightning current flows through the columns within the building structure reinforcement column (Yin Xiaxian) leaked into the ground when the Yin Xiaxian around would have a strong alternating magnetic field, in this cross - variable magnetic field under the influence of the internal circuitry of electronic equipment, high voltage generated by the sensor, breakdown of electronic components and integrated circuits.
1, power supply, network cabling unreasonable. The power lines, network lines for shielding is not grounded, the event of lightning, the power cord and network cable is very susceptible to lightning strikes or inductive lightning electromagnetic pulse, the lightning electromagnetic pulse along the power cord, network cable spread switches, microwave equipment, and will the damage.
2, broadband network equipment, microwave equipment, Deng Jun arresters for lightning protection is not installed.
The points are the computer networks, microwave equipment, relatively easy to influence by lightning causes. .
Fourth, the implementation of a comprehensive mine-awareness programs
1, the computer room of the ground and the building columns to repeat ground tendons to form a common ground so that ground to better release flood water. The engine room of the anti-static flooring, cabinet ground.
2, adjust the placement of the switch. As far as possible away from the structure of the building columns and facades, to reduce damage to the equipment lightning pulse.
3, adjust the wiring, power lines and signal lines as far as possible along the structural columns and wall installation, and power lines and signal lines laid shield.
4, installation of power and signal surge arresters:
(1) The selection and use of SPD Note Description:
a, should be selected within the different uses of different properties of SPD. SPD in the selection of the power supply system to be considered standard, rated voltage and other factors. For the signal SPD should be considered in the selection of SPD and electronic equipment compatibility.
b, SPD protection must be multi-level, for example, part of the room lightning protection of electronic devices in terms of power, or at least type of discharge pressure limiting type SPD and the SPD before and after the two protection.
c, at all levels to achieve effective co-ordination between the SPD, when the two SPD power lines or communication lines between the distance below the norm, should the two SPD decoupling between the adoption of appropriate measures.
d, built in cities, suburbs, mountain room under different circumstances, the design selection of over-voltage-type SPD, consider the network power supply uncertainties, the suitable operating voltage of the SPD.
e, the signal SPD should meet the signal transmission with the rate, work level, type of network needs, while interfaces should be compatible with the device.
f, the right to install in order to achieve the desired results. SPD installation should be provided strictly in accordance with the requirements of the factory installation.
(2) The power supply voltage limits are adopted three diversion measures will be the impact of lightning current on the power supply to a minimum. First-class office building housing a total distribution. Model: HD-D380B-XL80, characterized by-pass flow capacity, anti-jamming ability, residual down. Second level is located in the computer room at the power switch, model: HD-D220C-XS40, characterized by lightning arrester on the resulting over-voltage limit of pressure, especially suitable for the small network switch power protection. Third level are located in each switch, power switch at the server, model: HD-D220CZ.
(3) signals in the switch to the cascade port terminals and surge arresters are installed computer networks, model: HD-XNET-RJ45 / 4, characterized by low insertion loss and fast response time, the rate of up to 100M above, give full consideration to the future network development.
(4) Microwave equipment installation coaxial cable lightning arrester, model: HD-T1800, to prevent the lightning from the invasive microwave antennas.