Equigradient lines of electric field in stator slot, isodestruction lines of insulation and high voltage design of turbo- and hydrogenerators windings

The electrical aging of insulation used in high-voltage electrical machines in operation is investigated. Ionizational aging of multicomponent insulation is shown as a family of isodestruction lines which can be shown to relate to equigradient lines in the image of the electrical field. Results are then used to perfect the design of the insulation and high-voltage windings. The peculiarity of ionizational destruction of stator winding insulation during operation is reduced to long-term slow electrical aging of multicomponent dielectric partials which are regularly distributed and differ on corona resistance in conditions of sharply non-uniform electrical field at small operating level of its intensity. The process runs simultaneously in all volume of insulation, and its intensity in each point is determined by influencing intensity, by ability of insulation components to resist to it and by duration of aging