ZnO Gapless Lightning Arrester or Surge Arrester
An electrical surge can be occurred in an electrical power transmission system due to various reasons. Surge in electrical system originated mainly due to lightning impulses and switching impulses. Electrical surge produces a large transient over voltage in the electrical network and system. The shape of the transient over voltage has a steeply rising front with slowly decaying tail as shown in the figure below. This steep voltage wave travels through the electrical network and causes over voltage stresses on all the electrical insulators and equipment come under its travelling path.