METHOD OF COMPENSATION OF CURRENT TRANSFORMER ERRORS IN TRANSIENT MODES Russian patent published in 2018 - IPC H01F27/42 H01F38/28 

FIELD: electricity.

SUBSTANCE: fix the array of instantaneous values of the secondary current of the specified current transformer, calculate the flux linkage of the secondary winding and magnetic induction in its core. Then, by converting the magnetic induction, a signal proportional to the magnetizing current of the current transformer is obtained, and the resulting signal is summed up with a signal proportional to the secondary current of the current transformer, thereby obtaining a signal proportional to the primary current applied to the secondary circuit. When the instantaneous values of the secondary current are fixed, the saturation moment is additionally fixed, and before the appearance of the saturation signal of the core, the values of the primary current applied to the secondary circuit are equated to the values of the secondary current. After the appearance of a signal about the saturation of the core, the sign of the magnetic induction of the core saturation is determined by the sign of the instantaneous value of the secondary current. After this, the increment of flux linking and magnetic induction is calculated on the saturated portion of the magnetization characteristic of the core. Then the resulting increment of magnetic induction is summed up with the value of the magnetic induction of saturation and by converting the resulting sum a signal proportional to the magnetizing current is obtained. After this, the excess is also calculated and fixed by an integral, for example, effective value of the secondary current of a given level. If there is a signal that the integral value, for example, the effective value of the secondary current of a given level is exceeded, the signals proportional to the secondary and magnetizing currents are summed up, thereby obtaining a signal proportional to the primary current applied to the secondary circuit. If the integral, for example, effective value of the secondary current for a given time does not exceed a given level, then the value of the primary current applied to the secondary circuit is equated with the value of the secondary current.

EFFECT: increase the accuracy of error compensation by taking into account the initial residual magnetic induction in the core.

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