METHOD TO MEASURE CURRENT LOSSES AND EXCITATION CURRENT OF POWER TRANSFORMERS IN FIELD CONDITIONS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2014 - IPC G01R31/06 

FIELD: electricity.

SUBSTANCE: suggested method to measure current losses and excitation current of power transformers in field conditions and device for its implementation are referred to electric engineering and may be used for calculation and justification of standards for process power losses during its transmission through electric mains. The device comprises a controlled power source to change voltage at one winding of the transformer when the second winding is open. In order to reach the claimed result a free-running asynchronous generator with excitation capacitors is used as the controlled power source. Output voltage of the generator is controlled stepwise within the limits of 70-110% of rated voltage by reswitching of adjustment capacitors at transition of commutation voltage through zero value. Reswitching is made by three-phase contactless electronic keys controlled through optically coupled inputs by a decoder and a multiposition switch.

EFFECT: improved accuracy for real excitation losses of the power transformer.

2 cl, 3 dwg, 1 tbl