Because lightning generates a strong over-voltage and over-current, it is impossible to complete the discharge and voltage limit at one time. Therefore, the power supply system must adopt multi-level lightning protection. At least two levels of lightning protection must be taken before and after the discharge and voltage limiting. . According to the current lightning protection technical requirements of computer information systems in China, the power supply system should adopt three-level lightning protection, that is, install high-pass capacity lightning protection devices in each phase of the high-voltage end of the building's main distribution equipment, as the first-level protection, at low pressure.
The side-mounted valve type lightning protection device is used as the second-level protection, and the power lightning protection box is installed as the third-level protection in the floor distribution box. For important occasions, more levels of protection should be taken, such as installing a lightning arrester at the output of the UPS power supply, and installing a lightning protection device for the power terminal of the important equipment power input. Through the use of multi-level power lightning protection facilities, the lightning over-current is completely discharged, and the over-voltage is limited, so as to prevent lightning from entering the computer network system through the power line as much as possible, thereby damaging the system equipment.
In order to avoid the possibility of lightning strikes caused by the communication cable, the commonly used technique is to first access the signal lightning arrester (signal SPD) before the cable accesses the network communication device, that is, a transient over-voltage protector is connected in the link.
It can protect the electronic equipment from the lightning surge caused by lightning flash and other interference, block the intrusion of overvoltage and lightning waves, and minimize the impact of lightning on the system equipment. Since the signal lightning arrester is connected in series in the communication line, the signal lightning arrester must meet the requirements of network performance indicators such as signal transmission bandwidth in addition to the lightning protection performance characteristics. Therefore, when selecting related products, full consideration should be given to lightning protection performance indicators and network performance indicators such as network bandwidth, transmission loss, and interface type.