The tendency of AC Surge Protective Device

The tendency or behavior of an AC Surge Protective Device (SPD) refers to how it operates and responds to electrical surges or transient overvoltages in an alternating current (AC) power system. Here's a detailed overview:

Tendency of AC Surge Protective Device

Clamping Overvoltages

SPDs are designed to limit transient overvoltages (such as those caused by lightning strikes or switching operations) by clamping them to a safe voltage level.

When a surge occurs, the SPD activates and diverts the excess energy away from sensitive equipment.

High-Speed Response

SPDs typically respond in nanoseconds to sudden spikes, ensuring protection before the surge can damage connected devices.

Non-Linear Behavior

Under normal operating voltage, the SPD has very high impedance, drawing almost no current.

When a surge occurs, it becomes low-impedance, allowing the surge current to pass through it safely to the ground or neutral.

Self-Resetting (in most cases)

Many SPDs automatically return to their high-impedance state once the surge has passed.

Some models may require replacement if they experience a surge beyond their rated capacity.

Thermal Protection Mechanism

Advanced SPDs include thermal disconnects or fuses to prevent overheating or fire if the SPD is damaged or fails.

Degradation Over Time

SPDs can degrade with repeated surge events.

Their tendency over time is to become less effective, which is why monitoring and replacement schedules are important for critical systems.

Coordination with Grounding Systems

SPDs work in conjunction with the grounding system to safely divert surge energy.

A poorly grounded system can reduce the effectiveness of an SPD.

Types of Surges SPDs Handle

Lightning-induced surges

Switching surges

Load shedding/start-up surges

Electrostatic discharge (ESD)

If you are interested in our products or have any questions, please feel free to contact us and we will reply you within 24 hours.