Transformer winding

A transformer winding comprising:

• at least two axially adjacent winding modules which are hollow and arranged cylindrically around a common winding axis and include an electrical conductor wound in layers;
• and
• a common electrical insulation layer through which the winding modules are enveloped,
• wherein the insulation layer has, on its radially outer face, at least one ring-like radial depression or ring-like radial elevation which is salient transversely to the winding axis;
• and
• wherein the common electrical insulation layer has a wound insulation material and a flexible profiled strip, the flexible profiled strip being arranged transversely to the winding axis and wound in partially through the insulation material, thereby forming at least some of the radial ring-like depressions or elevations.