A winding insulation system includes a set of insulated conductors, main wall insulation provided around the conductors, corona shield tape provided around the main wall insulation, stress grading tape provided around the corona shield tape, and sealing tape provided around the stress grading tape. The main wall insulation includes inner, intermediate, and outer sections. The inner section includes polyimide mica paper reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the inner section being provided in half-lap layer(s). The intermediate section includes mica paper reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the intermediate section being provided in half-lap layer(s). The outer section includes mica tape backed with aramid and reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the outer section being provided in half-lap layer(s).