Power transformer

A power transformer, comprising a core, wherein the core comprises a limb and a yoke;

• a winding wound around the limb, wherein the winding has an extension along a main axis of the limb;
• an energy harvesting device comprises a ferromagnetic part and a coil wound around at least a portion of the ferromagnetic part;
• wherein the energy harvesting device is arranged in such a way that a part of a magnetic flux generated in the power transformer induces an electromotive force in the energy harvesting device;
• wherein the coil comprises a wire wound around a main axis of the coil;
• wherein the coil has an extension along the main axis of the coil which is less than the extension of the winding;
• wherein the energy harvesting device is designed and arranged to power a sensor of the transformer for sensing at least one of temperature, humidity, and pressure;
• wherein the energy harvesting device has a first end portion attached to the limb and a second end portion attached to the yoke and wherein the limb is connected with one end to the yoke and with a second, opposing end to a further yoke of the core;
• and
• wherein the ferromagnetic part is attached to the core via at least one permanent magnet.