SPD (Surge Protective Device, surge protector) is mainly used to prevent transient overvoltage caused by lightning strikes or grid switching operations from damaging equipment. The prices and applicable places of SPDS made of different materials and structures vary.

The common core component of SPD is zinc oxide varistor (MOV), which is relatively low in price and has a fast response speed. It is widely used in the protection of residential buildings, commercial buildings, distribution cabinets and industrial equipment. The price of MOV type SPD for common low-voltage distribution is generally from tens to hundreds of yuan.

SPD using gas discharge tubes (GDT) has a high current-carrying capacity and insulation performance, and is suitable for the protection of weak current lines in communication base stations, data centers, security systems, etc. Its price is usually higher than that of ordinary MOV products.

High-end SPD products will adopt a MOV+GDT combination structure. Some products are also equipped with thermal trip devices, fault indication and remote alarm functions, which offer higher safety and reliability. They are suitable for important places such as hospitals, power systems, rail transit, photovoltaic power stations and industrial automation control systems, with prices ranging from several hundred to several thousand yuan.

For ordinary office buildings, residences and shops, standard MOV type SPDS can be selected. For areas with frequent lightning activities, communication rooms, data centers and important industrial projects, it is recommended to choose combined or high-current capacity SPDS to enhance the lightning protection and overvoltage protection capabilities of the system and ensure the long-term stable operation of the equipment

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