The importance of SPD in lightning protection in switching power supplies
According to the "Code for Design of Lightning Protection of Buildings" GB50057-94 (2000 edition), buildings in LPZ0B, LPZ1, and LPZn+1 lightning protection zones should take measures to prevent induced lightning, static electricity, or power surges as appropriate. Induced lightning is a lightning strike caused by the strong electromagnetic field changes (electromagnetic pulse induction or static electricity induction) induced on conductors by lightning flash current, which poses a huge threat to electrical equipment, especially low-voltage electronic equipment, inside buildings. The key to lightning protection for internal equipment in buildings is to prevent the intrusion of induced lightning. In the protection against induced lightning, surge protectors (SPDs) are indispensable devices that can respond promptly to overvoltage and overcurrent in various circuits, discharge overcurrent in the circuit or clamp overvoltage on the circuit, thereby achieving the purpose of protecting electrical equipment.
Static electricity, surges, and induced lightning have the same properties and can all be suppressed by surge protectors (SPDs). Another form of static electricity generation is due to friction or high-speed operation of electronic devices, which generate a large amount of static electricity on the human body and electronic devices. High voltage discharge is prone to occur between people and objects, and between objects, which can easily damage precision electronic devices after discharge; Surge can occur in a wide range of daily situations, such as power on and off, power on and off, starting and stopping of elevators, electric gates, and motors, damage to drills, welding, electrical equipment, and short circuits in wires. In addition, power surges often occur inside the power system, causing the power supply to dry up
Lines, branches, generators, power distribution equipment UPS, Both AC and DC power sources, as well as electrical equipment terminals, may experience [2]. Compared with lightning, although the pulse voltage of a surge is lower, its pulse width, duration, and intensity are still not small, but they are sufficient to interfere with and damage electrical equipment.
