surge arresters has mainly two advantages: they are economical with respect to their level of technology and they can also be installed on existing systems, they are not necessarily indicated only on new systems. In reality, this device behaves like an equipotentializer that is inserted into the L-PE with an infinite Z impedance that allows you not to have to change the functionality of the system electrician in Canton, GA.
When they receive the overvoltage, the surge arresters called Surge Protection Devices (SPD) make the impedance drop through the absorption of the charge produced. At this point a draining maneuver takes place which will establish the voltage in a constant way in order to make it compatible with the equipotentializing and insulating levels of the equipment.
It must be understood that not all surge arresters systems have the same quality and characteristics.
We have mainly 3 groups:
1) Triggering and switching
Here the work is delegated to the spark gap which is a device with 2 electrodes spaced in the air. When the overvoltage occurs between the two electrodes, an electric arc opens. This system is reliable, has galvanic isolation, adequate dimensions and a high discharge current.
2) Limiting surge arresters
A technique with varistors composed of zinc oxide and other particles which, when an overvoltage occurs, are crossed by a current but are able to keep the voltage at the terminals constant while the overvoltage is absorbed. The intervention time is very short and they are precise systems.
3) Combined type surge arresters
How much typology is the simplest as there is a series connection of the first two types of SDP. The insulation is galvanic and no follow current is generated. Or in the parallel connection there is the advantage of a reduced tripping time, high discharge currents, a rather low protection level Up and good tripping accuracy.
After having clarified the question to answer is:
Which surge arrester to choose?
Choosing one system rather than another is therefore not very simple. Let’s say that the characteristics to be evaluated are the plate data.