The Surge Protection Device is an indispensable device in electronic equipment lightning protection.
The role of "lightning arrester" or "overvoltage protector" is the role of SPD. Surong protector is to restrict the instantaneous over -voltage of the electric power line and signal transmission line in the voltage range that the equipment or system can withstand, or it will be powerful Lightning current is leaked into the place where the protected equipment or system is not damaged by impact.
The type and structure of the waves are different according to different uses, but it should contain at least one non -linear voltage limit element. The basic components used for surge protectors are: discharge gaps, inflatable discharge pipes, voltage resistance resistance, inhibit the diode and choke coil.
Divide
- Power line SPD
Because the energy of lightning strikes is very huge, the method of leaking the lightning strikes is gradually leaked to the earth through a classification method. At the junction of the LPZ0A or in the junction of the Level 1 Classification Test at the junction of the LPZ0B (LPZ0B) and the first protection zone (LPZ1) First -level protection, leakage the direct strike of lightning current, or when the power transmission line is directly lightning strike, the huge energy of the conductive is released. After the first zone (including the LPZ1 area) at the junction of the first protective area, install a limited -level surge protector as a second, third or higher -level protection. The second -level protector is aimed at the residual voltage of the predecessor's protector and the protective equipment for sensing lightning strikes in the area. When a large lightning strike energy is absorbed in the front stage, there are still a part of the equipment or third -level protector. The energy will be transmitted, and the second -level protector needs to be further absorbed. At the same time, the transmission line of the first level of lightningware will also sensorize lightning electromagnetic pulse radiation. When the line is long enough, the energy of the lightning lightning becomes large enough, and the second -stage protector needs to be further implemented on lightning energy. The third -level protector protects the remnant lightning energy of the second -level protector. According to the resistance level of the protected equipment, if two levels of lightning protection can be limited to the resistance level of the voltage below the equipment, only two levels of protection can be done; if the equipment of the equipment is low, it may require level 4 or even even level More levels of protection.
Choose SPD, first of all, you need to understand some parameters and its working principles.
⑴ 10/350 μs wave is a waveform that simulates direct lightning, and the waveform energy is large; 8/20 μs wave is a waveform that simulates lightning induction and lightning.
⑵ Named discharge current in refers to the peak current flowing over SPD and 8/20 μs current waves.
(3) The maximum discharge current IMAX is also called the maximum flow volume, which refers to the maximum discharge current that can be affected by 8/20 μs current wave impact.
耐 Maximum continuous resistance UC (RMS) refers to the maximum AC voltage effective value or DC voltage that can be continuously applied to SPD.
指 Residual pressure UR refers to the residual voltage value under the rated discharge current.
表 Protect the voltage UP to characterize the voltage characteristic parameters between the SPD restricting the terminal of the terminal. Its value can be selected from the list of preferably, and it should be greater than the highest value of the voltage.
P Voltage switch -type SPD is mainly leaked by 10/350 μs current waves, and the limited voltage SPD is mainly leaked by 8/20 μs current waves. - Signal line SPD
The signal line SPD is actually a signal lightning molar. It is installed in the signal transmission line. It is generally at the front end of the device to protect the follow -up equipment and prevent the thunderbolt from pouring from the signal line into the damage device.
1) Selection of voltage protection level (up)
The UP value should not exceed the targeting device's impact voltage rated value. UP requires that the SPD and the protected device should have a good cooperation.
In the low -voltage power supply and distribution system device, the equipment should have a certain tolerant electrocomputer, that is, the ability to impact over voltage. When the 220/380V three-phase system has been obtained, the voltage value of various equipment is available, and it can be selected according to the given indicators of IEC 60664-1 and GB 50057-1994 (2000 edition).
2) Named discharge current in (impact stream capacity) selection
The peak current of the SPD and 8/20 μS current waves. It is used to do II classification tests for SPDs, and it is also used for pre -processing of SPD class I and II classification tests.
In fact, IN is the maximum impact current peak that SPD does not have substantial destruction and can be maximized by specified times (generally 20 times), specified waveform (8/20 μs).
3) Selection of the maximum discharge current IMAX (extreme impact stream capacity)
The peak current of the SPD and 8/20 μS current wave is used for II classification test. IMAX and IN have many the same. They use the peak current of the 8/20 μS current wave to perform II classification tests for SPD. The difference is also obvious. IMAX only does an impact test on the SPD. After the test, the SPD does not have substantial damage; and IN can do 20 such tests. After the test, the SPD cannot be substantially damaged. Therefore, IMAX is an impact current limit value, so the maximum discharge current is also called the limit impact stream capacity. Obviously, imax> in.
Divide according to working principles
Classified by its working principle, SPD can be divided into voltage switch, voltage limit, and combined type.
⑴ Voltage switch -type SPD. When there is no instantaneous overvoltage, high impedance is presented. Once the instant voltage of the lightning is responding to the lightning, its impedance will change to low impedance. The lightning current is allowed to pass. It is also called "short -circuit switch -type SPD".
D d SPD. When there is no instantaneous overvoltage, it is high impedance, but the impedance will continue to decrease with the increase of electricity and voltage. The current voltage characteristics are strong and non -linear, and sometimes it is called "clamp voltage SPD".
(3) Combined SPD. Combined by the voltage switch component and limited voltage component, it can be displayed as a voltage switch type or limited voltage type or both characteristics, which determines the characteristics of the voltage increase.
Lightning characteristics
Lightning protection includes external lightning protection and internal lightning protection. The external lightning protection is mainly to connect to the flash device (lightning needle, lightning protection net, lightning protection belt, lightning protection line), leading down line, and grounding device. The main function is to ensure that the building body is exempted from direct lightning attacks. The lightning of the building is leaked into the earth through lightning rods (bands, nets, lines), and down line. Internal lightning protection includes measures such as lightning protection, surge in lines, land potential counterattacks, lightning wave invasion, and electromagnetic and electrostatic induction measures. This method is to use equal potential connections, including direct connection and indirect connection through SPD, so that metal, equipment lines and earth form a conditional potential body. The diversion and induction of internal facilities caused by lightning strikes and other waves will Lightning current or wave current leakage into the earth, thereby protecting the safety of personnel and equipment in the building.
Lightning is characterized by the rise in voltage (within 10 μs), high peak voltage (tens of thousands to millions), large current (tens to hundreds of thousands), shorter maintenance time ), Fast transmission speed (spread at the speed of light), the energy is very huge, it is the most destructive type of wave voltage.
Basic Features
Langyong protector SPD - Protecting the flow of large amounts, extremely low residual pressure, and fast response time;
- Adopt the latest arc extinguishing technology to completely avoid the fire;
- Use temperature control protection circuit, built -in heat protection;
- With a power supply state instruction, the working status of the surge protector in indicator;
- Strict structure, stable and reliable work.
