Transient Drift Dominated Conduction in Dielectrics

A generalized transient analysis has been developed using a drift dominated conduction model to solve for the electric field and space charge distributions in a dielectric for any initial and boundary conditions as well as for any type of terminal excitation or constraint. Past results for parallel plate electrodes were extended to lossy dielectrics with ohmic conductivity. Analogous methods were developed for concentric cylindrical and spherical electrodes. The case of bipolar conduction including charge recombination is also treated. The method of characteristics was used throughout this study so that the governing partial differential equations were converted into a set of first order ordinary differential equations. For current excitations, these equations are easily integrated while for voltage excitations the equations are in the correct form for Runge-Kutta numerical integration. Special cases examined include the charging transients to a step voltage or current from rest or from a pre-stressed level and the discharging transients for systems in the dc steady state which are instantaneously opened or short circuited.