Various phenomena occur in gaseous dielectric when a voltage is applied. When the applied voltage is low, small currents flow between the electrodes and the insulation retains its electrical properties. If the applied voltages are large, the current flowing through the insulation increases very sharply, and an electrical breakdown occurs. The concept of breakdown will be assumed to signify the collapse of the dielectric strength of air between two electrodes, which is in practice defined by the collapse of the voltage that had previously been sustained between them. High voltages used for a wide variety of applications covering the power systems, industry and research laboratories. Therefore is necessary to make a thorough investigation in the electrical discharge in air.
