Based on international electrical standards and practical application scenarios, Surge Protective Devices are divided into distinct types with unique performance characteristics and application ranges, which are detailed below:
1. Type 1 Surge Protective Devices
Type 1 SPDs are designed for primary lightning protection of power systems. They are installed at the main power intake of buildings, substations, and large industrial power distribution centers. They can withstand and discharge extremely high lightning impulse current, effectively resisting direct lightning strikes and strong induced lightning surges. Their core advantage is large current discharge capacity, which can release megaampere-level lightning energy, providing the first line of defense for electrical systems.
2. Type 2 Surge Protective Devices
As the intermediate protection device of the power system, Type 2 SPDs are installed in floor distribution boxes and workshop branch power cabinets. They mainly suppress residual overvoltage after Type 1 protection and absorb conventional grid switching surges and load mutation surges. They have excellent voltage clamping performance and moderate current discharge capacity, serving as the core conventional protection device for most power distribution systems.
3. Type 3 Surge Protective Devices
Type 3 SPDs are terminal fine protection devices, installed directly in front of precision electronic equipment, computers, PLC instruments, and communication terminals. They cannot bear large current surges but have ultra-low residual voltage and extremely fast response speed, which can eliminate tiny residual surge interference that cannot be suppressed by Type 1 and Type 2 SPDs, protecting high-precision sensitive equipment from subtle voltage damage.
4. Power SPD and Signal SPD
Power SPDs are used for AC and DC power circuit protection, adapting to power frequency voltage surges of power distribution systems. Signal SPDs are specially developed for low-voltage signal transmission lines such as network cables, telephone lines, and sensor lines. They feature low signal attenuation and high anti-interference performance, ensuring normal signal transmission while completing surge protection.
5. Household and Industrial SPDs
Household SPDs are miniaturized, low-power devices for residential electrical systems, with simple functions and low cost. Industrial SPDs are high-performance, high-reliability devices with waterproof, dustproof, explosion-proof, and thermal protection functions, suitable for complex and harsh industrial power environments.