Surge Protective Devices can be classified systematically according to protection level, working principle, application scenario, and installation position, forming a complete classification system to adapt to different electrical system protection requirements. The complete classification is as follows:
1. Classification by IEC protection level (most mainstream industrial classification)
Type 1 SPD: Also known as lightning current arrester. It is installed at the total power incoming end of buildings, power distribution rooms, and substation outlets. It is mainly used to discharge huge direct lightning surge current and has an extremely large discharge capacity, suitable for resisting strong lightning impact energy.
Type 2 SPD: Also known as overvoltage suppressor. It is installed in the secondary distribution cabinet of buildings and workshops. It undertakes the task of secondary suppression of residual lightning surges and grid switching surges, with balanced discharge capacity and voltage clamping performance, which is the most widely used SPD type.
Type 3 SPD: Also known as terminal precision protector. It is installed at the front end of precision electrical equipment and intelligent terminals. It features ultra-low voltage residual pressure and high precision clamping performance, aiming to eliminate tiny residual surges and protect sensitive electronic components.
2. Classification by working principle
Varistor-type SPD: Adopts metal oxide varistors as the core component, with fast response speed and low cost, suitable for most conventional power surge protection scenarios.
Gas discharge tube-type SPD: Uses gas discharge principle for discharge, with large current resistance and strong lightning resistance, mostly used for primary lightning protection.
Semiconductor-type SPD: Adopts TVS diode components, with ultra-fast response and high precision, suitable for signal circuit and precision equipment protection.
3. Classification by application scenario
Civil household SPD: Small size, low discharge capacity, suitable for household power sockets, household appliances, and residential building power distribution systems.
Industrial SPD: High discharge capacity, environmental resistance, and intelligent monitoring function, suitable for industrial power distribution, automation equipment, and outdoor engineering systems.
Signal SPD: Specialized for network lines, communication lines, and instrument signal lines, protecting system signal transmission from surge interference and damage.
4. Classification by installation structure
Module-type SPD: Rail-mounted modular design, easy installation and replacement, convenient for later maintenance, widely used in power distribution cabinets.
Integrated SPD: Integral sealing structure, high protection level, suitable for harsh outdoor and wet environments.