With the continuous development of modern power systems, AC surge protection devices (SPD) are playing an increasingly important role in power systems. AC SPD can effectively protect electrical systems and equipment from transient voltages and surges, providing safety assurance for industrial, commercial, and residential applications. This article will explore the selection and application of AC SPD to help users better understand and use this critical device.

AC surge protection device (SPD) is a device connected to the AC (AC) network, designed to protect electrical systems and equipment by limiting transient voltages and diverting surge currents. Transient voltages and power surges pose significant risks to individuals and equipment, hence surge protection plays an important role in safety.
According to IEC standards, low-voltage power supply systems can be divided into TT, TN , and IT systems. The TN system is further divided into TN-C, TN-S, and TN-CSsystems. The appropriate SPD should be chosen based on the grounding method of the low-voltage power supply system. For example, in a TN AC power supply system, the distribution lines drawn from the main distribution box of the building must adopt the TN-S grounding method.
According to IEC 61643-11:2011 and EN 61643-11:2012+A11:2018 , AC SPD can be divided into three types:
Suitable for the main distribution equipment of buildings, the SPD 100kA rating is capable of withstanding direct lightning currents, providing robust protection for critical infrastructure.
Used to protect distribution equipment within the building.
Used to protect end equipment, usually installed near the equipment.
When selecting an SPD for AC power systems, the following basic considerations must be taken into account:
Determine whether the power supply is single-phase or three-phase.
Determine the voltage protection level of the SPD. The impulse withstand voltage of the protected electrical equipment should be greater than the voltage protection level UP of the SPD.
Ensure to select the correct number of ports or sockets.
Check if the SPD is a transient voltage surge protector and if it has the TUV mark.
It is crucial to choose SPD of the appropriate specification. If the SPD is chosen too large, the system will not be harmed but the cost will increase; if chosen too small, the system may fail faster.
Certified SPD typically includes fault indicators (such as indicator lights or signs), making it easy for maintenance personnel to determine whether the SPD is functioning properly. Regular inspection is necessary, and SPD devices with non-function indicators should be replaced as soon as possible.
The equipment used on industrial sites is very sensitive and prone to being affected by lightning and switching surges. Professional lightning and surge protection methods will ensure the long-term stable operation of industrial site equipment. By installing AC SPD on key equipment and distribution systems, equipment failures caused by surge voltages can be effectively reduced, thereby enhancing the safety and reliability of industrial production.
AC SPD plays an important role in protecting electrical systems and equipment from surge voltage damage. Through the reasonable selection and correct application of AC SPD, the safety and reliability of power systems can be greatly improved. If you have any questions or needs regarding the selection and application of AC SPD, feel free to contact Techwin.
Signal Surge Protector: Safeguarding Electronic Systems Against LightningDecember 12, 2024The surge protector is an electronic device that provides safety protection for various electronic equipment, instruments, and communication lines. According to its use, it can be divided into power s...view
The Difference Between Surge Protector and Miniature Circuit BreakerJune 20, 20221. Surge protectorSurge protector, also known as lightning protector, is a protection device designed to prevent various electronic equipment, instruments, and communication lines from being subjected...view
Do surge protectors protect against lightning?November 28, 2023In the realm of electronic device protection, surge protectors often take center stage. Many homeowners invest in these devices to shield their gadgets from power surges caused by various factors. How...view
What is a Surge Protector?October 25, 20211. Surge protectorA surge protector is a small electrical device with two functions. The first function is to allow multiple components to be plugged into the same power outlet. The second function, w...view
Common Signal Surge Protective Devices and Their Industry ApplicationsOctober 9, 2024What is a Signal Surge Protective DeviceA signal surge protective device is an electronic device that protects instruments, equipment, or systems on the signal line from damage caused by lightning str...view
How Power Supply Protection Devices Work Unseen To Ensure Device SafetyJanuary 10, 2024In the modern world, where our daily lives are intricately intertwined with electronic devices, ensuring the safety of these devices is of paramount importance. Power supply protectors play a crucial,...view