Power supply lightning protector (SPD), also known as lightning arrester, surge protector, surge protector. In the information age, computer networks and communications equipment is increasingly sophisticated, the requirements of its working environment is also increasingly high, and lightning and large electrical equipment transient overvoltage will be more and more frequent through the power supply, antennas, radio signal transceiver equipment and other lines into the indoor electrical equipment and network equipment, resulting in equipment or component damage, casualties, transmission or storage data interference or loss, and even make electronic equipment malfunction or temporary paralysis, system stoppage, data transmission interruption, LAN or even WAN damage. The damage is alarming, and the indirect loss is generally much larger than the direct economic loss. Power supply lightning protector is to prevent equipment from being struck by lightning through modern electricity and other technologies.

Development history Editorial voice
The most primitive lightning arrester is ram-horn shaped gap, appeared in the late 19th century, used for overhead transmission lines, to prevent lightning damage to equipment insulation caused by blackouts, so called "lightning arrester". 1920s, aluminum lightning arrester, oxide film arrester and pill arrester appeared. 30s appeared tubular lightning arrester. 50s appeared silicon carbide lightning arrester. 70s appeared metal oxide lightning arrester In the 1970s, metal oxide lightning arrester appeared. 1992 onwards, the industrial control standard 35mm rail snap-in pluggable SPD lightning protection module, represented by Germany and France, began to be introduced into China on a large scale, and later the integrated box power lightning protection combination, represented by the United States and the United Kingdom, also entered China.

Principle
There are two types of power surge protector: the explosion-proof box type and the modular type. Both use voltage-sensitive resistors with excellent non-linear characteristics. Under normal conditions, the surge protector is in a very high resistance state and the leakage current is almost zero, thus ensuring normal power supply to the power system. When a surge overvoltage occurs in the power system, the power surge protector immediately conducts within nanoseconds, limiting the amplitude of the overvoltage to the safe working range of the equipment, while the surge energy is channeled into the ground and released. The surge protector then rapidly changes to a high resistance state again, thus not affecting the normal power supply.

Performance features
1. large protection flux, very low residual voltage, fast response time
2. the latest arc extinguishing technology, completely avoiding the occurrence of fire
3. Adopt temperature control protection circuit, built-in thermal protection
4. with power status indication, showing the working status of the surge protector
5. Rigorous structure, stable and reliable operation [1].