Surge protective devices connected to low-voltage power systems
Surge protectors protect electrical equipment against damage from surges/overvoltages that are higher than the equipment can withstand. Overvoltage is defined as a voltage that is twice the rated voltage. Dangerous are transient overvoltages that reach high amplitudes in a very short time. Overvoltages can penetrate systems through low-voltage power lines, through power transformers and equipment circuits, through control, measurement, data and telecommunication lines and sensor lines, especially if they are located outside the building or on pipelines, tracks, etc. In the event of an electronic system being attacked by a surge pulse, the individual parts do not behave in isolation but interact with each other, even though they may not be galvanically connected. The surge always finds its way towards the grounded parts or to other lines representing a distant ground. The main principles of pulse surge protection are: external lightning protection - lightning conductor system; internal lightning and surge protection - surge protection device. Surge protection devices are installed at the interface of the individual LPZ zones, where they are also connected to the appropriate equipotential bonding system.