ERROR COMPENSATION METHOD FOR CURRENT TRANSFORMER Russian patent published in 2014 - IPC H01F27/42 H01F38/28 

FIELD: electricity.

SUBSTANCE: invention is related to electric engineering and may be used in systems of relay protection, measurement and emergency control equipment. The error compensation method for current transformer includes preliminary determination of leakage inductance for the secondary winding, hysteresis losses and eddy currents of the current transformer, which are used as the basis for calculation of loss resistance. The current transformer is coupled to the primary circuit of the power system. Current-voltage converter is coupled to the secondary circuit of the transformer. An analogue-to-digital converter is connected to the converter output; with the preset time frame the ADC measures instantaneous voltage values proportional to the secondary current of the transformer and generates a digital code corresponding to the instantaneous value of the secondary current of the transformer. Instantaneous values of flux linkage derivative are determined by calculation of the first and next approximations of flux linkage derivative between the primary and secondary windings by formula. Thereafter integration and calculation is made for the first approximation of flux linkage derivative, a new value of excitation current is determined for the current transformer against induction-permeability curve, and the difference is defined between the new value and the accepted one.

EFFECT: reducing error of the primary current recovery in transient modes, stability of the primary current recovery and increase of operating speed.

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