Visible to the public Analysis of zero-mode inrush current characteristics of converter transformers

TitleAnalysis of zero-mode inrush current characteristics of converter transformers
Publication TypeConference Paper
Year of Publication2021
AuthorsLiu, Zhichang, Yin, Xin, Pan, Yuanlin, Xi, Wei, Yin, Xianggen, Liu, Binyan
Conference Name2021 56th International Universities Power Engineering Conference (UPEC)
KeywordsAnalytical models, Attenuation, compositionality, converter transformer, cyber physical systems, inrush current, Internet of Things, pubcrawl, remanence, Resiliency, Resistance, Surge protection, Surges, sympathetic interaction, Transformers, Windings, zero-mode inrush current
AbstractIn recent years, there have been situations in which the zero-sequence protection of the transformer has been incorrectly operated due to the converter transformer energizing or fault recovery. For converter transformers, maloperation may also occur. However, there is almost no theoretical research on the zero-mode inrush currents of converter transformers. This paper studies the characteristics of the zero-mode inrush currents of the converter transformers, including the relationship between the amplitude and attenuation characteristics of the zero-mode inrush currents of converter transformers, and their relationship with the system resistance, remanence, and closing angle. First, based on the T-type equivalent circuit of the transformer, the equivalent circuit of the zero-mode inrush current of each transformer is obtained. On this basis, the amplitude relationship of the zero-mode inrush currents of different converter transformers is obtained: the zero-mode inrush current of the energizing pole YY transformer becomes larger than the YD transformer, the energized pole YD becomes greater than the YY transformer, and the YY transformer zero-mode inrush current rises from 0. It is also analyzed that the sympathetic interaction will make the attenuation of the converter transformer zero-mode inrush current slower. The system resistance mainly affects the initial attenuation speed, and the later attenuation speed is mainly determined by the converter transformer leakage reactance. Finally, PSCAD modeling and simulation are carried out to verify the accuracy of the theoretical analysis.
DOI10.1109/UPEC50034.2021.9548277
Citation Keyliu_analysis_2021