The overvoltage protectors are designed to damping the transient overvoltage of an atmospheric or an industrial source.

This overvoltage might rise in all kind of electric supply wires, as low voltage, instrumentation, control and order, computers, etc.

They could be produced by direct stroke of lightning on the distribution lines, or by induction, due to intense electromagnetic fields generated by lightning.

Transmission Lines

The transmission lines, as telephone lines, antennas, computer network, and any other conductor of control and order, are susceptible of transmitting parasite currents generated by coupling during a storm activity.

These lines are protected at the way in, as well as, at the way out with adapted devices such us the surge arresters types DR, BNC.

There are very specific and technique Standards for the installation of surge arresters: IEC 61.644-1, ITU K11, 12, 17, 20, 21, 22, 36, UL 497 A/B.

Low Voltage Electrical Network

The protection of low voltage electrical network with surge arresters, has the aim to protect the rest of the equipment of the network, as well as the equipment connected to it.

There are very specific and technique Standards for the installation of surge arresters: NFC 61740 / VDE 0675 / UL 1449 / IEC 61643-1-1.

The principle of cascade protection requires several protector scales.

• The first protection level is located at the beginning of the installation. It consists on surge arresters of high energy - maximum discharge current between 150 and 70 KA. Its goal is to break the perturbation wave and drive most of its energy to earth.
• The residual voltage applied to the electric equipment is quick and limited thanks to a second level of protection made by varistors, for more admissible currents - maximum discharge current 40 KA.
• When it is needed, depending on the susceptibility of the equipment, a third protection level is used, with more sensitive protectors - maximum discharge current 10 KA. Also, if a technical consideration allows it, depending on the installation and equipment, there can be places in which it is recommend using the third level protectors (10 KA) at the second level.