Principle And Function Of Surge Protector

Surge protection devices (SPDs), often referred to as "lightning arresters" or "overvoltage protectors," are essential for lightning protection of electronic equipment. The function of an surge protective device is to limit transient overvoltages entering power lines and signal transmission lines to within the voltage range the equipment or system can withstand, or to divert strong lightning currents into the ground, protecting the protected equipment or system from damage.

The surge protector operates as follows: It is typically installed at both ends of the protected equipment and grounded. Under normal operating conditions, it presents high impedance to normal power frequency voltage, allowing almost no current to flow, effectively acting as an open circuit. When a transient overvoltage occurs in the system, the surge protection device presents low impedance to high-frequency transient overvoltages, effectively short-circuiting the protected equipment.