Lightning is electrostatic discharge during which electrically charged regions in the atmosphere and ground temporarily equalize/neutralize, causing the instantaneous release of energy.
During the Thunderstorm, Clouds are charged like giant capacitors, where upper side of Cloud is positive charged and bottom side is negative charged.
As the Strength of Electric Field in the clouds increases during thunderstorm, negative charge at the bottom of the clouds pushes earth surface electrons in the deep bottom in the earth hence earth surface acquire strong positive charge.
Now, strong electric field in the thunder storm region pushes break down of air, that is ionization of Air happens – Plasma is created, which forms conductive path between clouds and earth surface and allow current flow to neutralize the charge separation.
Lightning energy is in Giga Joules.
Thunderstorm Lightning.
Switching of high Inductive loads.
The purpose of surge arrester is to protect equipment from high DV/DT peak instantaneous Voltage surge, which is more than Uimp Impulse withstand voltage of the equipment.
The purpose of a surge arrester is to protect insulation/components from high DV/DT that peak at instantaneous values that are in excess of the breakdown of the insulation or component.
Lightning Arrester > 1000 V AC Operating Voltage Ue.
Surge Protection Devices SPD < 1000 V AC Operating Voltage Ue.
Lightning arrester diverts Lightning surge to ground without impacting on supplies of power frequency voltages.
Lightning arrester does not absorb the lightning, nor it stops lightning. It limits the Voltage produced by lightning and diverts the lightning current to the ground. It protects the equipments in parallel to the Arrester.
Lightning arrester has MOV-metal oxide veristor like material, which acts as insulator for normal operating voltage however it acts as conductor for lightning higher voltages.
Lightning Protection system, Protects from direct lightning strike on the building or on the transmission lines.
Surge Protection system, Protects electrical Network and electrical Equipment from surges