Surge Protectors: Basic Principles And Applications

A surge protector is a device used to protect electrical and electronic systems from transient power surges. It protects equipment by limiting transient overvoltages and discharging surge currents, preventing damage caused by lightning, switching overvoltages, and other factors. The following is detailed information about surge protectors:

How Surge Protectors Work

Surge protectors operate using internal nonlinear components, such as varistors (MOVs), gas discharge tubes (GDTs), or semiconductor devices (such as TVS diodes). Under normal operating conditions, these components present high impedance to voltage, allowing almost no current to flow. When a transient overvoltage occurs in the system, these components rapidly switch to a low impedance state, allowing current to flow and thus discharging the overvoltage to ground, protecting the equipment from damage.

Types of Surge Protectors

• Switching Type: Presents high impedance when there is no surge; in response to a lightning surge overvoltage, the impedance abruptly drops to a low value, allowing lightning current to flow.

• Voltage-Limiting Type: Presents high impedance when there is no surge, but its impedance continuously decreases as the surge current and voltage increase, limiting overvoltage.

• Combined Type: Combining switching and voltage-limiting components to provide multiple layers of protection.

Surge Protector Installation Methods

When installing a surge protective device, choose a suitable installation location, ensuring an appropriate distance between it and the protected equipment, and proper grounding. Different types of SPDs are suitable for different system configurations, such as TT, TN-S, and IT systems; the corresponding wiring methods should be followed during installation.

Surge Protector Purchasing Guide

When purchasing a surge protector, consider the following key parameters: protection level (Up), residual voltage (Uc), impulse current (Imax), energy value (W), shunt factor (α), response time (tr), withstand voltage (Ue), leakage current (Il), and operating temperature range (Ta). Select the appropriate SPD type and specifications based on the application scenario and equipment type.

Surge Protector Application Scenarios

Surge protectors are widely used in power systems, electronic equipment, petrochemicals, intelligent buildings, and transportation, providing protection for various equipment and systems.

By understanding the working principles, types, installation methods, and purchasing guidelines of surge protection device, you can better select and use surge protectors to protect your electrical and electronic systems from transient power surges.