A Novel Approach to Current Transformer Characterization in the Presence of Harmonic Distortion

Electromagnetic Current Transformer Transfer Characteristics under harmonics load

“…At the same time, we can see that the angular difference is a linear function of the frequency, and the conclusion is consistent with the results from the delay perspective of the literature [10], which is mainly caused by the time effect [10]. [7] shows that the actual signal is generally the fundamental wave superposition of harmonic, and it is considered that the current transformer is a nonlinear element, and the single frequency method may lead to inaccurate measurement, so the method of the fundamental wave superposition method is used to measure [7]. When the fundamental wave is under rated current, we consider to change the harmonic content, phase angle and frequency, and then observe and analyze the fundamental error and the harmonic error in various conditions.…”

Estimation of the inductive current transformer derating for operation with distorted currents

“…Consequently, the composite error always indicates the highest possible value of current error or phase displacement. In accordance with IEC standard 60044-1 [9], the composite error is determined for protection CTs and the limiting values of this error for measuring CTs are not defined by this IEC standard but they may be calculated from formula (1) for limiting values of current error and phase displacement defined in this standard. Calculated limiting values of composite error for measuring CTs are presented in Table 1.…”

“…In these conditions and for transients inductive instrument transformers are characterized by significantly worst metrological properties than at rated frequency of sinusoidal primary signal [1][2][3][4][5][6][7]. The increase of transformation error for distorted voltage/current will increase the error of indirect measurements of power and electric energy.…”

A practical approach to evaluation of accuracy of inductive current transformer for transformation of distorted current higher harmonics

“…Electronics CT/VT characterization in the presence of harmonic distortion is determined for test signal, which contains only main harmonic and one higher harmonic. Similar approach was described in [9], as a method for inductive CT characterization in the presence of harmonic distortion. However, due to nonlinearity of magnetization curve of magnetic core the approach with one higher harmonic in used for test distorted * Correspondence to: Department of Instrument Transformers and Electromag- signal does not allow a proper assessment of accuracy of harmonics transformation.…”