2020 | vol. 68 | nr. 1 | art. 7

Measurement of Transformer Core Loss based on Low-Frequency Triangular Wave

Xuejun Chen, Ning Yang, Yongming Yang
For the no-load test of transformer with large capacity and voltage level, it is difficult to manufacture large-capacity variable-frequency sine wave power supply. In order to reduce the capacity and manufacturing difficulty of test power supply, a separation measurement and equivalent method of transformer core loss based on low-frequency triangular wave is proposed. This method is based on Bertotti's core loss separation model, constructs a matrix equation, uses the principle of least squares method to solve the hysteresis loss coefficient, eddy current loss coefficient and excess loss coefficient, and then converts core loss to that under power frequency (50 Hz) sine wave excitation. In addition, in the case of whether excess loss is considered, the analysis and comparison after conversion are carried out respectively. The experimental results show that the core loss based on the proposed method has a good agreement with that under the same frequency actual sine wave excitation. When the voltage amplitude is below 115V, the relative errors of the core losses without considering excess loss are smaller than those converted with excess loss. While the voltage amplitude is greater than 115V, the relative errors of the former are greater than the latter. And in both cases, except for the start of the test, the relative errors between the calculated core losses of triangular wave and the measured sine wave are less than 2.8%. This method has high conversion accuracy and engineering application value.
Keywords: Triangular wave, Transformer, Core loss, Low-frequency method, Least square method
To cite this article: Xuejun Chen, Ning Yang, Yongming Yang, “Measurement of Transformer Core Loss based on Low-Frequency Triangular Wave”, in Electrotehnica, Electronica, Automatica (EEA), 2020, vol. 68, no. 1, pp. 59-67, ISSN 1582-5175.