Study on models of the HVDC converter transformer for calculation of high-frequency interference

Two models of converter transformers for calculation of high-frequency (HF) interference in the converter station are proposed. Based on the analysis of the traditional simple model, a modified model is brought out to simulate the high-frequency and relative low-frequency performances of converter transformer at the band 1-500 kHz, considering the capacitance between windings and the earth capacitance of low- voltage winding, and above 20 kHz a simplified pure capacitance model can be used to replace the modified model regardless of the leakage inductance. Besides, a method to determine the parameters of the two models is presented. Then the models of converter transformers are applied to GUI-GUANG project, and the result shows that the modified model and its simplified pure capacitance one can meet the requirement of calculation of high- frequency interference.