Measuring arrangement for detecting a magnetic unidirectional flux in the core of a transformer

A compensating device for compensating a magnetic unidirectional flux in an electrical transformer, comprising:

• a sensor which detects the unidirectional flux in at least one rod-shaped core limb having a winding;
• wherein:
• a) the sensor is formed from a ferromagnetic sensor core enwound by a sensor coil;
• wherein:
• b) the sensor is arranged along a section of the rod-shaped core limb and adjacent to the winding of the rod-shaped core limb, said section being predetermined by a winding width of the winding of the rod-shaped core limb, said sensor being also arranged in one of (i) a cooling channel of the rod-shaped core limb and adjacent to the winding of the rod-shaped core limb and (ii) an annular space formed by an outer peripheral surface of the rod-shaped core limb and an inner peripheral surface of the winding of the rod shaped core limb, such that a magnetic flux is partially diverted from the rod-shaped core limb and guided over at least one non-ferromagnetic gap formed between the outer peripheral surface of the rod-shaped core limb and the inner peripheral surface of the winding of the rod-shaped core limb;
• wherein:
• c) the sensor core is prism shaped and extends in a longitudinal direction which is oriented in a direction of a limb axis during use of the sensor;
• wherein:
• d) a length of the sensor core is more than twice its width;
• wherein:
• e) the ferromagnetic sensor core and the sensor coil are formed together as an insert in a bar-shaped suspension device;
• wherein:
• f) the bar-shaped suspension device includes a carrier comprising a fiber-reinforced synthetic material;
• and
• wherein:
• g) the carrier includes a longitudinally extending shell-like recess for receiving the sensor.

A method for compensating a magnetic unidirectional flux in a magnetic core of an electrical transformer, comprising:

• detecting, via a compensating device which is supplied with a sensor signal from a sensor, the unidirectional flux, the sensor being formed from a ferromagnetic sensor core enwound by a sensor coil;
• and
• arranging the sensor along a section of a rod-shaped core limb having a winding and adjacent to the winding of the rod-shaped core limb in one of (i) a cooling channel and (ii) an intermediate space between an inner peripheral surface of the winding and a side face of the rod-shaped core limb, such that a magnetic flux is partially diverted from the rod-shaped core limb and guided over at least one non-ferromagnetic gap formed between an outer peripheral surface of the rod-shaped core limb and an inner peripheral surface of the winding of the rod-shaped core limb, said section being predetermined by a winding width of the winding of the rod-shaped core limb
• wherein the sensor core is prism shaped and extends in a longitudinal direction which is oriented in a direction of a limb axis during use of the sensor;
• wherein a length of the sensor core is more than twice its width;
• wherein the ferromagnetic sensor core and the sensor coil are formed together as an insert in a bar-shaped suspension device;
• wherein the bar-shaped suspension device includes a carrier comprising a fiber-reinforced synthetic material;
• and
• wherein the carrier includes a longitudinally extending shell-like recess for receiving the sensor.