2026-09-ALF

The gas discharge tube arresters, also known as GDT, are widely used protective components that can protect electrical equipment from voltage surges induced by lightning, direct strokes, and switching operations. It is composed of an arrester body, a capacitor and an internal gas discharge unit that consist of a gas-filled metal tube and a thin metal wire. The ALF application field and working principle provide a detailed explanation in the following sections.

1. ALF Application Field

Alf gas discharge tube arresters are used in many areas, including high-voltage power grids, telecommunications system, computers, fire safety systems, and more. They can protect these systems from large amount of voltage surge, and maintain power continuity in the case of a surge, even while having to withstanding physical/chemical aspects. Its applications are categorized in four fields, including resource, industry protection, engineering protection and earthquake protection.

Resource and industry protection are in charged with defending the industrial environmental from occasional over-voltage due to lightning strike or switching surge. It is also used to protect the public buildings of sensitive materials from lightning strikes. Engineering protection, on the other hand, offers protection against overvoltage and voltage transients which appear at point of connection into electric power system. This involves the protection of technological equipment and human personnel, as well as the insulating materials contained in such equipment. The earthquake protection field focuses on the protection against any environmental damaging caused by accidental short-circuit or leakage due to strong and frequent earthquakes.

2. Working Principle

When a voltage surge or high frequency transient current appears in the system, ALF gas discharge tube arresters are designed to instantaneously and accurately identify the voltage levels and to ensure that it is lower than the arrester limits. It is then able to support and reduce the voltage until it is safely discharged outside the system. By doing so, the pressure on the system is greatly reduced, which prevents any potential damage to the system. Furthermore, the internal metal tube, which is filled with gas, helps to absorb any voltage over the arrester limits.

In normal working states, the inner thin metal wire, which is connected in parallel with the low pass filter, provides low impedance discharge. When a high voltage surge appears, it can be detected by the leakage current. As the inner wire passes the voltage to the gas, the gas gets charged until the uneven electric field is balanced again, thus discharging the potential difference entirely.

Conclusion

The ALF gas discharge tube arresters are very effective and commonly used as protective components for electrical equipment from voltage surges induced by lightning, direct strokes, and switching operations. It contains a capacitor and an internal gas discharge unit that consists of a gas-filled metal tube and a thin metal wire which helps to absorb any voltage over the arrester limits. Furthermore, they can be used in many areas, including high-voltage power grids, telecommunications system, computers, fire safety systems, and more.