study of discharge zones of long air gaps under switching impulse conditions \

The need. for further investigation the phenomena of discharges in air gaps is a must, in view of the increase transmitted powers arid transmission voltages.The present work aims at examining the stages of a discharge in long sir gas under an impulse of 75/LOO ms in shape which lies well within the range of impulses most critical to air insulation.Beginning at an applied voltage which is insufficient produce corona pulses, the applied. volt is systematically increased allowing corona First to appear at random and then rather definitely.the voltage is further increased unti1 a probable breakdown materializes and finally a level of voltage is reached at which breakdown in certain.The gap configuration leading to a direct break down and a quasi—uniform field breakdown are experimentally sought.