Transformer with shielding rings in windings

A coil and electric shielding arrangement for a dry-type transformer, the electric shielding arrangement comprising:

• a winding wound around a longitudinal axis of the transformer forming the coil;
• an electric shielding device arranged at a distance from the winding at an axial end of the winding perpendicular to the longitudinal axis and parallel to a to surface of the coil such that the electric shielding device covers a cross-sectional area of the winding perpendicular to the longitudinal axis, the electric shielding device having first rounded edges not facing the winding, and second rounded edges facing the winding, wherein a radius of the first rounded edges and a radius of the second rounded edges are adapted such that an electric shielding of the winding is provided by the electric shielding device;
• and
• an insulation material attached to the winding and to the electric shielding device, the insulation material establishing a first distance between the winding and the electric shielding device along the longitudinal axis such that the winding is shielded against another electric field,
• wherein the winding and the electric shielding device are casted in a block which insulates the electric shielding device from the electric field of the winding by providing a second distance between the winding and the electric shielding device,
• wherein the casted block includes third rounded edges near the electric shielding device with radii corresponding to the radii of the first rounded edges of the electric shielding device, and
• wherein the electric field generated by the windings is smoothed by a combination of the electric shielding device with the first rounded edges and the third rounded edges of the cast block near the first rounded edges.