Electric transformer with an increased total leakage impedance

An electric transformer comprising:

• a winding assembly, the winding assembly comprising a primary coil and a secondary coil;
• and
• a first magnetic circuit, the first magnetic circuit magnetically coupling the primary and secondary coils,
• wherein the first magnetic circuit comprises a first limb and a second limb connected together by an upper and a lower yoke to form a magnetic loop around a central passage, the first limb extending along a vertical axis,
• wherein the primary coil comprises an inner primary coil and an outer primary coil, the inner and outer primary coils being connected in series and wound around the first limb of the first magnetic circuit,
• wherein the secondary coil is wound around the first limb of the first magnetic circuit,
• wherein the inner primary coil, the secondary coil, and the outer primary coil are cylindrical and arranged concentrically around the vertical axis so that the inner primary coil is received inside the outer primary coil and the second coil is accommodated between the inner and outer primary coils,
• wherein the winding assembly forms a column around the first limb,
• wherein the inner primary coil, the secondary coil, and the outer primary coil are mounted in a manner to maintain a predefined inner gap between the inner primary coil and the secondary coil and a predefined outer gap between the secondary coil and the outer primary coil, the inner and outer gaps being evaluated along a radial direction relative to the vertical axis, the inner and outer gaps increasing a leakage of a magnetic flux between the primary coil and the secondary coil, and
• wherein the winding assembly further comprises a secondary magnetic circuit, forming a magnetic loop around the secondary coil only, the secondary magnetic circuit extending, in a horizontal plane transverse to the vertical axis, along a portion of the secondary coil, the second magnetic circuit amplifying the leakage of the magnetic flux between the primary coil and the secondary coil.