2017-15-SMC-RPLF Circuit Protection

Gas Discharge Tube Arresters (GDT)

Gas Discharge Tube Arresters (GDT) is a type of Surge Protective Device (SPD) used for the protection of electrical devices and systems against transient overvoltages caused by lightning or other electrical events.

GDTs are typically installed at the point of greatest exposure to transient overvoltages created by lightning in a power system, such as near power lines. They differ from other types of SPDs in that they are designed to rapidly discharge large volumes of energy in a very short period of time, typically less than 1 microsecond.

GDTs are made up of a protective tube which contains an inert gas, usually nitrogen, inside. This gas is used to rapidly dissipate any sudden increase in voltage on the protected side of the tube, thus blocking its passage. The protective layer consists of a pair of aluminium foil electrodes which are spaced apart to create a uniform electric field.

A 2017-15-SMC-RPLF application field is the protection of DC and low-voltage AC applications, such as DC systems, communication equipment, industrial control systems, consumer electronics, and residential electronics. This type of arrester is designed to be applied with a minimum operating voltage of 15VAC and with a peak transient current handling capacity of 200A.

The working principle of 2017-15-SMC-RPLF application field is based on the electronic process of Townsend ionization. In this process, a high intensity electric field will cause an avalanche ionization process inside the tube which accelerates the free electrons and ions in the tube and causes them to impact with nitrogen atoms in the tube to produce nitrogen oxides and ozone.

The accelerated electrons and ions induce a current flow across the electrodes which discharges the energy stored in the tube and limits the peak current passing through the protected device. As the current flow dissipates, the arrester is off again and the protective electric field inside the tube is restored. This entire process occurs within a few microseconds.

As with all types of SPDs, GDTs are designed to dissipate energy during transient overvoltages and protect the connected equipment from damage or destruction. GDTs provide excellent protection against lightning and other transient overvoltages, while being relatively smaller in size compared to other types of SPDs.