Zero-Sequence Differential Current Protection Scheme for Converter Transformer Based on Waveform Correlation Analysis
| Autor: | Zheng Tao, Chengqi Zhang, Guo Xingchao, Xingguo Wang, Yang Xinhui |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Control and Optimization
Correlation coefficient Converter transformer Computer science zero-sequence differential current protection correlation analysis CT saturation 020209 energy Energy Engineering and Power Technology 02 engineering and technology lcsh:Technology law.invention Control theory law 0202 electrical engineering electronic engineering information engineering Waveform Electrical and Electronic Engineering Transformer Engineering (miscellaneous) Neutral current Renewable Energy Sustainability and the Environment lcsh:T Waveform correlation 020208 electrical & electronic engineering Inrush current Correlation analysis Energy (miscellaneous) |
| Zdroj: | Energies, Vol 13, Iss 1814, p 1814 (2020) Energies; Volume 13; Issue 7; Pages: 1814 |
| ISSN: | 1996-1073 |
| Popis: | Through the analysis of the recovery inrush current generated by the external fault removal of the converter transformer, it is pointed out that the zero-sequence current caused by the recovery inrush may result in the saturation of the neutral current transformer (CT), whose measurement distortion contributes to the mis-operation of zero-sequence differential current protection. In this paper, a new scheme of zero-sequence differential current protection based on waveform correlation is proposed. By analyzing the characteristics of zero-sequence current under internal fault, external fault and external fault removal, the waveform correlation of the zero-sequence current measured at the terminal of the transformer and the zero-sequence current measured at the neutral point of the transformer is used for identification. The polarity of the CT is selected to guarantee the zero-sequence currents at the terminal and neutral point of the transformer exhibit a "ride through" characteristic under external fault, then the waveform similarity is high, and the correlation coefficient is positive. On the other hand, when internal fault occurs, zero-sequence current waveforms on both sides differ from each other largely, and the correlation coefficient is negative. Through a large number of simulations verified by PSCAD/EMTDC, this criterion can accurately identify internal and external faults, exempt from effects of the recovery inrush. Moreover, it presents certain ability for CT anti-saturation. |
| Databáze: | OpenAIRE |
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