The function of lightning arrester and its wide application
May 20, 2022
The function of lightning arrester and its wide application
There are more and more types of electronic and electrical products, and their application fields are becoming more and more extensive, and communication equipment is gradually developing in the direction of miniaturization. In hardware design, in order to improve the service life of electronic products, special attention should be paid to the surge voltage resistance level of electronic products. Electronic products generally have lower impulse withstand voltage levels than low-voltage power distribution installations and are therefore vulnerable to voltage fluctuations - ie, surge voltages. In the 220V circuit system, there will be voltage fluctuations that can reach 5000 or 10000V instantaneously, that is, surges.
Surge, also known as transient overvoltage, is an instantaneous voltage fluctuation that occurs in a circuit, usually lasting about one millionth of a second in a circuit. Surge is also called surge, as the name implies, it is an instantaneous overvoltage that exceeds the normal operating voltage. Essentially, a surge is a violent pulse that occurs in just a few millionths of a second. Possible causes of surges are: heavy equipment, short circuits, power switching, or large engines. Products containing surge blocking devices can effectively absorb large bursts of energy to protect connected equipment from damage.
Surge protector, also known as lightning arrester, is an electronic device that provides safety protection for various electronic equipment, instrumentation, and communication lines. When a surge current or voltage is suddenly generated in an electrical circuit or communication line due to external interference, the surge protector can conduct the shunt in a very short period of time, thereby avoiding the damage of the surge to other equipment in the circuit. Under normal conditions, the surge protector is in a high resistance state, and no leakage occurs; when an overvoltage occurs in the circuit, the surge protector will be triggered in a very short time, leaking the energy of the overvoltage to protect Equipment; after the overvoltage disappears, the surge protector returns to the high-impedance state, which will not affect the normal power supply of the power supply at all. Lightning arrester is a combination of overvoltage protection electronic devices that can withstand high currents of hundreds of amperes, and is used in parallel on power supply lines and signal transmission lines. When it encounters lightning strikes and high voltage and high current, it will appear short circuit immediately, and the main power switch will be disconnected at the same time, so that the computer equipment is protected.
The most primitive surge protector, the claw-shaped gap, appeared in the late 19th century and was used for overhead transmission lines to prevent lightning strikes from damaging equipment insulation and causing power outages, so it is called "surge protector". Modern high voltage surge protectors are used not only to limit the overvoltage caused by lightning in the power system, but also to limit the overvoltage caused by the operation of the system.
During thunderstorms, lightning pulses can cause voltage fluctuations in electrical circuits. There are many lightning areas in my country, and lightning is an important factor that generates surge voltage in the line. Therefore, it is very necessary to strengthen the lightning protection in the low-voltage power distribution system. Due to the large-scale popularization of communication networks and the miniaturization trend of communication equipment, there are more intrusion paths for communication equipment by lightning. As shown in the figure below, antennas, signal lines, power lines, ground lines, and network lines can all be its input paths.
Therefore, there are corresponding types of power surge protector, communication surge protector, LAN surge protector, ground-to-ground SPD, and antenna feeder SPD, and different types correspond to different possible intrusion paths. Anxun's lightning protection products are readily available, and there are external lightning protection devices that meet the IEC61643-11 test standard. In addition, there are surge protectors with different application directions, such as CRCC certified surge protectors, photovoltaic surge protectors, CATV surge protectors, and explosion-proof surge protectors.
The circuit of the surge protector has different forms and combinations according to different needs. Due to the huge energy of lightning strikes, it is necessary to discharge the energy of lightning strikes to the ground gradually through the method of graded discharge. The first-level lightning protection device can discharge the direct lightning current; the second-level lightning protection device is a protection device for the residual voltage of the previous-level lightning protection device and the electromagnetic pulse radiation LEMP induced by lightning strikes in the area; the third-level lightning protection device It is to protect the LEMP and the residual lightning strike energy passing through the second-level lightning arrester.
As shown in the figure below, the first-level lightning arrester limits the surge voltage of tens of thousands to hundreds of thousands of volts to 2500-3000V, and its lightning current flow is not less than 60KA. It can prevent lightning waves of 10/350μs and 100KA, reaching the highest protection standard specified by IEC. The residual voltage value is not greater than 2.5KV; the response time is less than or equal to 100ns.
The second-level lightning arrester further limits the value of the residual surge voltage passing through the first-level lightning arrester to 1500-2000V, the maximum surge capacity is more than 45kA per phase, the required limiting voltage should be less than 1200V, and the lightning current capacity is greater than or equal to 40KA (8/20μs); the peak value of residual voltage is not more than 1000V; the response time is not more than 25ns.
The third-level protection reduces the value of the residual surge voltage to within 1200V, so that the energy of the surge will not damage the equipment. When the power lightning arrester installed at the AC power inlet end of the electronic information equipment is used as the third-level protection, it should be a series voltage limiting type power supply lightning protection device, and its lightning current capacity should not be lower than 10KA.
The above is the introduction of the function of the lightning arrester and its wide application. I hope it will be helpful to you.