What Exactly Is Surge Protective Device? Can It Really Prevent Lightning Stroke?

- Apr 07, 2020-

The recent Wenzhou is always rainy, even the air is cold and humid. But it's not summer now, or it's not just rain, there's lightning. In addition to the obstacles to travel caused by thunderstorm, the lightning generated by thunderstorm will also cause damage to the computer host and power supply at home, which is caused by a surge current generated by lightning, rather than random or accidental lightning.

In essence, surge is a kind of transient over-voltage that exceeds the normal working voltage in only one millionth of a second. Besides lightning, short circuit of heavy equipment, power switch and large engine may cause surge. The surge protector with surge arrester can effectively absorb the sudden huge energy, so as to avoid equipment damage.

The most primitive surge protective device (SPD) appeared in the late 19th century, but it was used for overhead transmission lines to prevent the line insulation and power failure caused by lightning damage to equipment. Then in the 1920s, there were aluminum surge protectors, oxide film surge protectors and pill surge protectors. In the 1930s, there were surge protective devices (SPDs), in the 1950s, there were silicon carbide lightning arresters, and in the 1970s, there were metal oxide surge protective devices (SPDs).

Generally, arc extinguishing technology is used in surge protective devices, that is to say, the process of contact making and breaking current is often accompanied by the generation and extinction of arc, so it is necessary to analyze the cause of electric spark and solve it. In addition, the thermal protection device will be built in the surge protector to protect the circuit together with the arc extinguishing technology and completely avoid the occurrence of fire.

But the more advanced the electronic equipment is, the more vulnerable it is to be damaged by lightning, which also puts forward higher requirements for lightning arresters. In order to meet the requirements of information system equipment tolerance, the installation of surge protective devices can be carried out in multi-level cooperation, but the energy overlap between each protector should be considered in multi-level cooperation, and it is better to use the same kind of products from the same manufacturer if conditions permit.