Modelling and experimental research of the non-stationary processes of conduction and space charge accumulation in dielectric liquids

The non-stationary processes of conduction and space charge accumulation in dielectric liquids are characterised by the current-time dependencies, by maximum in the curves of the voltage-current characteristics, recorded for different time intervals, by maxima in the curves of the reversal currents and by non-linear distribution of the electric field in the interelectrode spaces. The nature and purity of the dielectric liquids and conditions on the electrode-liquid contacts determine the features of all these dependencies, where the electrochemical reactions can occur. For description of the current-time characteristic the physical and mathematical model of conduction of dielectric liquids can be used. This model supposes that the dielectric liquid contains a small amount of electrolytic impurities and represents homogeneous medium with constant permittivity. Analysis of the numerical modelling shows that for time in an interval longer than the chemical relaxation time, the charging current does not change in time. Nevertheless, as it follows from experimental data, the current in dielectric liquid can be dropped for a long much longer than the chemical. This process is sufficiently complicated and it needs further investigation. For description of the current, as a function of time in the quasi-steady-state range the developed model based on the attenuated memory principle [2] is proposed.