Electronic surge protectors , such as signal lightning protectors, are a crucial component of internal lightning protection devices. Signal lightning arresters, as opposed to equipment lightning arresters, are more concerned with protecting signal transmission lines from lightning damage, including analog, digital, and video signal transmission protection. This is done to avoid signal interruption or signal quality damage brought on by lightning surge. With the quick advancement of information technology, signal lightning arresters are used in a wider variety of applications nowadays, and there are an increasing number of models available.
The type of signal lightning arrester should be carefully chosen in accordance with the relevant requirements.
1、 Classification of signal lightning arrester
1. Cable TV lightning arresters, twisted-pair transmission lightning arresters, communication signal lines lightning arresters, satellite receiver antenna lightning arresters, and host and service lightning arresters are all parts of the low level data signal portion of data signal lightning protection.
2. The signal system and apparatus are safeguarded by the twisted pair signal protector (overvoltage protection connector). The maximum discharge current Ismax of each line is 10kA (8 x 20 s), and the response time is 10ns. The rated voltage is 100 VAC/DC.
3. Industrial control signal lightning arresters, such as the signal lightning arrester, 16-channel video signal lightning arresters, clamping rail lightning arresters, coaxial thick cable communication signal lightning arresters, coaxial thin cable communication signal lightning arresters, single-channel video lightning arresters, measurement and engineering control signal lightning arresters, RS485 signal lightning arresters, and monitoring multi-function lightning arresters are all references.
4. The serial port protector is a plug-in adaptor with an over-protection circuit that is used to safeguard signal systems and hardware and can be applied in situations where there is a high volume of transmission. The host and server, for instance, are positioned in front of the serial port to protect it. The maximum discharge current Ismax is 15kA, the rated voltage is 8V and 12V, and the data transmission rate is 1Mbit/s. The data transmission rate is 1Mbit/s, with a rated discharge current of 100A and a rated voltage of 12V DC for fine protection.
5. The computer system using 75 - 93 interfaces is protected by the coaxial cable signal protector. The thick and thin cable network cards are mounted in front of it, and its maximum amplification current, Ismax, is 20 kA (8 x 20 s). Its data transmission rate is 16 Mbit/s. Equipment of the 75 system, including antenna amplifiers, broadcast satellite reception systems, etc., are protected by overvoltage protectors of broadcast satellite antenna feeder (cable TV lines). The frequency range is between 4 and 2050 MHz, and the maximum discharge current, Ismax, is 3.5 kA (8 20 s).
2、 Working principle of signal lightning arrester
An example of electrical equipment that is used to guard against damage from lightning overvoltage, switching overvoltage, and power frequency transient overvoltage is the signal lightning arrester. In general, it is to discharge the high lightning current to the ground to keep the protected equipment or system from being damaged by impact, or to restrict the transient overvoltage into the power line and signal transmission line to the voltage range that the equipment or system can handle.
Several electrical and electronic devices connected to the power board will get current from the power socket during operation of the signal signal lightning protector. The signal signal lightning arrester will transfer any excess current to the ground wire of the power socket in the event that a surge or spike is formed and the voltage is higher than the permitted limit.
Metal oxide rheostats, sometimes known as MOVs, are a typical component in signal lightning protection devices. A metal oxide substance sits in the centre of the MOV, which also has two semiconductors attached to the ground wire and power supply. To transfer extra voltage, it joins the live wire with the ground wire.
These semiconductors' variable resistances change depending on the applied voltage.
The mobility of electrons in the semiconductor will result in exceptionally high resistance when the voltage is lower than a specific threshold. Contrarily, the electronic motion will alter and the semiconductor resistance will be significantly reduced when the voltage surpasses the desired value. The MOV will be inactive if the voltage is normal. The MOV may carry a lot of current and remove excess voltage when the voltage is too high.
The live line voltage will return to normal as the extra current is routed via the MOV to the ground, causing a sharp rise in the MOV's resistance once more. This ensures that the equipment attached to the signal signal lightning arrester continues to receive power from the regular current while only transferring the surge current through the MOV.