Transformer for fastening to a mast of an energy distribution network

A transformer for mounting on a mast of an air-insulated energy distribution network, having:

• a winding block having a solid insulating body, and at least one higher-voltage winding and at least one lower-voltage winding disposed in said solid insulating body, wherein said winding block delimiting an entirely peripherally closed central retention opening;
• a core unit having at least one magnetizable core being inductively coupled to said at least one lower-voltage winding by means of said at least one higher-voltage winding, wherein said at least one magnetizable core having at least one core limb and a ring portion, said core unit extending through said retention opening by means of said at least one core limb and annularly enclosing said winding block on an exterior by means of said ring portion;
• and
• a retainer for fastening said ring portion to the mast, said retainer including a supporting frame which entirely encloses said ring portion, said supporting frame containing a closed peripheral sidewall with a C-shaped cross-section, which entirely encloses said ring portion.