Electrical length of sulphur hexafluoride (SF6) at high pressure and at the liquid state

Author.Breakdown voltage of liquid SF6 at pressures higher than the critical one was measured. At the same time, investigations of electrical strength of gas SF6 at low and high densities (from 27 g/L to 1194g/L) were carried out for temperature T=50 oC, 60 oC. Breakdown voltage was measured with Rogowski profile electrodes at distances 0.4 mm. For low and high density SF6 gas. Good agreement was found between measured and calculated values by using a simple ionization development model for discharge initiation and microirregularities effect on the electrode surface structure. For liquid SF6 at pressure higher and lower than the critical one. It is supposed that the breakdown in the liquid occurs as result of a breakdown of bubbles which assumed that appears spontaneously in a local volume of liquid over heated caused by prebreak down currents