Lightning arrester is the equipment of substation to protect equipment from lightning shock wave attack. Arrester according to its development sequence can be divided into: protection clearance - is the simplest form of arrester; Tubular arrester - is also a protection gap, but it can be in the discharge after their own arcing; Valve type arrester is to separate a single discharge gap into many short series gap, while increasing the nonlinear resistance, improve the protection function; Magnetic blow arrester -- the use of magnetic blow spark gap, improved the ability of extinguishing arc, but also has the ability to limit the internal overvoltage; Zinc oxide lightning arrester, takes advantage of the volt-ampere characteristics of zinc oxide valve ideal (high nonlinear, namely in the large current when the features of low resistance limits the voltage on the lightning arrester, under normal power frequency voltage is of high resistance), with no gap, no stream low residual strength, can also limit internal overvoltage, are widely used. 

When the lightning shock wave passed into the substation along the way exceeds the protection level of the lightning arrester, the lightning arrester first dischards, and the lightning flows through the good conductor into the earth safely, and the lightning voltage amplitude is limited by the grounding device to the lightning impact level of the protected equipment, so that the electrical equipment is protected.