On-line detection of transformer excitation parameters based on fundamental wave extraction

The safe and stable operation of transformer is very important to the operation of power system. The excitation parameters can reflect the health and operation state of transformer winding, and the real-time monitoring of transformer excitation parameters is of great significance for the elimination of potential faults. At present, the identification of transformer excitation parameters is based on the excitation current containing harmonic components, which is difficult to calculate and requires a lot of calculation. In this paper, a fundamental wave extraction method based on the Second-Order Generalized-Integrator Frequency-Locked-Loop (SOGI-FLL) is introduced. The SOGI-FLL is used to extract the fundamental wave of the primary and secondary side voltage and current, and the transformer circuit equation is used for calculation, and then the excitation impedance parameters of the transformer are obtained. Finally, the effectiveness of the identification method for transformer condition monitoring is verified by experiments.