Comparison of voltage distribution in end-winding of synchronous generator

The electrical field in the end winding is nonlinear and its increase causes gliding partial discharges. To suppress the undesirable effect of partial discharges the end-winding corona protections (ECP) are applied. This protection is generally either varnish or tape. The essential property of the end winding corona protection is its nonlinearity. When the electrical field increases, the resistivity of ECP decreases. Thus, the voltage distribution along the stator bar gets more linear and so the possibility of gliding partial discharge occurrence minimizes. This article describes behavior of electric filed distribution in dependency on length of ECP and applied voltage.