Kiloamp Technology - The Global Provider of Electronic Security Protection
Kiloamp 2018-08-28 686
Design Basis
GB50057-2010 "Building Lightning Protection Design Code"
GB50343-2004 "Building Electronic Information System Lightning Protection Technical Specifications"
QX3-2000 "Weather Information System Lightning Strike Electromagnetic Pulse Protection Specification"
GB18802 "Surge Protector (SPD) for Low Voltage Distribution System"
IEC61312-1, 2, 3 "Protection of Lightning Electromagnetic Pulses"
GB50169-92 "Code for Construction and Acceptance of Grounding Device for Installation of Electrical Installations"
GB50194-93 "Safety Specifications for Power Supply and Use at Construction Sites"
With the rapid development of economic construction, the application of electronic information equipment has penetrated into various fields of national economy, national defense construction and people's life. Various electronic and microelectronic equipments have been widely used in various industries. Due to the low overvoltage resistance of these systems and equipment, the electromagnetic effects and thermal effects caused by lightning high voltage and lightning electromagnetic pulse intrusion will cause interference and permanent damage to the system and equipment. The lightning system damages the system and equipment, usually through the ground potential counterattack, various coupling mechanisms (current coupling, inductive coupling, capacitive coupling) and electromagnetic pulse radiation to enter the equipment along the power supply line, communication line, network line and metal pipeline. Causes damage to systems and equipment. Therefore, in lightning protection design, in addition to anti-direct lightning protection measures, lightning protection electromagnetic pulse protection measures should be considered, and perfect lightning surge overvoltage protection measures should be established, according to the characteristics of the protected buildings and the form of low-voltage power supply systems. Select and install a surge protector.
First. Lightning protection system lightning protection design
According to the division of lightning protection zones in GB50343-2004 "Technical Specifications for Lightning Protection of Building Electronic Information Systems", the lightning protection for important systems should be divided into three zones and considered separately. Only a single-level lightning protection may bring damage to the equipment caused by excessive residual voltage or insufficient protection capacity due to excessive lightning current. The multi-level protection of the power system protects against overvoltages at all levels from direct lightning strikes to industrial surges.
1, the first level power supply lightning protection design:
According to the relevant national regulations on low-voltage lightning protection, external metal lines should be buried in the metal pipe trenches for more than 15 meters before entering the building, and a low-voltage lightning arrester should be installed at the entrance end of the building. The main power supply lightning arrester at the low-voltage end must be installed at the inlet end of the power supply, and the high voltage of the lightning strike that may be introduced by the external circuit is led to the earth to ensure the safety of the subsequent equipment.
Install Kiloamp I-class power surge protector KPA385-2531R, 25kA (10/350μs), or Kiloamp power lightning protection box KPF385-12031R, 120kA (8/20μs), can be tens of thousands or even hundreds of thousands of volts The overvoltage is limited to several kilovolts, and the lightning arrester is installed in parallel at the incoming end of the main power distribution room to protect the lightning strike and the conducted lightning.
2, the second-level power supply lightning protection design:
Although the first-stage lightning arrester has been installed at the main power inlet end, when a large lightning current enters, the first-stage lightning protection device can discharge most of the lightning current from the ground line, and the remaining lightning power The residual voltage is still quite high, so the installation of the first-stage lightning arrester can reduce the large-scale lightning damage accident, but it does not ensure that the rear-end equipment is safe; assume that the power supply from the power distribution room is pulled to the power lines of other buildings. All are three-phase wiring, and there is also the possibility of inductive lightning current and secondary intrusion of lightning waves. It is necessary to install a second-level lightning protection device in the distribution cabinet.
The KPB385-8040R is installed here. The 80kA (8/20μs) can further limit the overvoltage of several kilovolts to less than 2 kV. The buildings in the lightning-prone zone need to have a flow capacity of 80KA. The residual voltage of the lightning generated after the first-stage lightning protection device is discharged and the lightning current induced in the power supply line are again discharged. This level of lightning protection device is installed in parallel, and the power of the subsequent equipment is not limited.
3, third-level power supply lightning protection design:
This is also the most overlooked place in system lightning protection. Modern electronic devices use many integrated circuits and precision components. The breakdown voltage of these devices is often only a few tens of volts, and the maximum allowable operating power is only mA. If the third-level lightning protection is not done, the residual voltage of the lightning strike entering the equipment after the first- and second-level lightning protection will still be above 1000 volts, which will cause a great impact on the rear-end equipment and cause damage to the equipment. .
Here, the Kiloamp Class III power surge protector KPB385-4020R, 40kA (8/20μs), can effectively limit the residual voltage to within kilovolts. This class of lightning arresters is installed in parallel, and the power of the connected devices is not limited.
4, the fourth level power supply lightning protection design:
For some of the more important weak electrical equipment, especially the data room, monitoring room, etc., although the third level of lightning protection has been done in front, there are still some lightning strikes and residual pressure into the equipment. In order to prevent the equipment from being damaged due to the impact of lightning current, it should be The power supply socket of the equipment adopts Kiloamp lightning protection socket or PDU, the maximum flow capacity is 10KA, and the socket system is usually the national standard three flat, universal, IEC C13, C19, and other international mainstream standards. Here, the lightning protection socket or PDU is the terminal power distribution equipment, and the power of the rear load equipment is required, usually from 2KW to 15KW.
Second, the power system lightning protection device selection installation plan
Third, the power supply system lightning protection device installation precautions
The lightning protection and grounding of the power line should meet the following requirements:
(1) It is not advisable to use overhead lines for the power lines of the electronic information system room.
(2) When the electronic information system equipment is powered by the TN AC power distribution system, the distribution line must adopt the grounding method of the TN-S system.
(3) The rated voltage withstand voltage of the distribution line equipment shall comply with the relevant regulations.
(4) A surge protector or a voltage-limiting surge protector that passes the I classified test shall be installed at the junction of the direct strike lightning protection zone (LPZOA) or the direct lightning protection zone (LPZOB) and the first protection zone (LPZ1). As the first-level protection; a voltage-limiting surge protector should be installed at the junction of each zone (including LPZ1 zone) of the first anti-expansion zone. For information equipment using DC power, depending on the operating voltage requirements, an appropriate DC power surge protector should be installed.
(5) The connection line of the surge protector should be straight and its length should not be greater than 0.5m. When the line length between the voltage switch type surge protector and the voltage limiting type surge protector is less than 10m and the line length between the voltage limiting type surge protectors is less than 5m, the relationship between the two levels of surge protectors shall be Add decoupling device. When the surge protector has an automatic energy matching function, the length of the line between the surge protectors is not limited. The surge protector should have an overcurrent protection device and should have a degraded display function.
(6) The number of surge protectors installed shall be determined according to the immunity of the protected equipment and the lightning protection rating.
(7) The nominal discharge current parameter value of the surge protector used for the power line should be in accordance with relevant regulations.
Fourth, power supply system lightning protection device operation and maintenance
1. After the lightning arrester is installed, check that all wiring is properly installed, then run the test to see if the system and equipment are working properly, and if there are any abnormalities, if any, check it in time until the entire system is operating normally.
2. The grounding system should be inspected and maintained before the thunderstorm season. Mainly check whether the joint is tight, the contact is good, the grounding down the line is rusted, and there is no abnormality on the ground near the grounding body. If necessary, the ground should be dug up to check the rust of the underground part. If problems are found, they should be dealt with in time.
3. The grounding resistance of the grounding grid should be measured once a year.
4. The lightning protection device in operation should be tested once a year before the thunderstorm season, and the appearance inspection should be strengthened during the thunderstorm season. If abnormalities are detected, it should be dealt with in time.
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