Influence of Phase Compensation Method on Magnetizing Inrush Identification
- 1 Department of Electrical Power Engineering, Kunming University of Science and Technology, Kunming, China
- 2 Department of Electrical Power Engineering, Kunming University of Science and Technology, Kunming, China
Abstract
The effect of different phase compensation methods on second harmonic ratio of magnetizing inrush is investigated. The flux linkage expression of switching on an unload transformer is deduced and influence factors of inrush current are analyzed firstly. Then the difference of two kinds of phase compensation methods, from star to delta and from delta to star connection, is compared. The second harmonic ratio of symmetric inrush is analyzed specially. Using inrush waveform of a real transformer, second harmonic ratio of phase inrush and that of differential current under two kinds of phase compensation methods are calculated respectively. Furthermore, based on the calculation results, the effect of two kinds of phase compensation methods on the inrush current identification is proved. The analysis and calculation results show that the second harmonic ratio of symmetric inrush caused by phase compensation method, from star to delta, is not low. Moreover, the split-phase blocking scheme should not be adopted for differential protection of from delta to star compensation. Using the phase current without compensation to calculate the ratio of second harmonic is inadvisable too.
- J. D. Hang and W. Q. Luo, “New Algorithm to Identify Inrush Current Based on Improved Mathematical Morphology,” Proceedings of the CSEE, Vol. 29, No. 7, 2009, pp. 98-105.
- M. M. Eissa, “A Novel Digital Directional Transformer Protection Technique Based on Wavelet Packet Transform,” IEEE Transactions on Power Delivery, Vol. 20, No. 3, 2005, pp. 1830-1836. doi:10.1109/TPWRD.2005.848646
- D. Z. Chen, J. D. Huang and L. Zhang, “Identification of Transformer Excitation inrush Based on Correlation Analysis between Two Fourier Algorithms,” Electric Power Automation Equipment, Vol. 30, No. 10, 2010, pp. 71-74.
- E. Vazquez, I. I. Mijares, O. L. Chacon, etc, “Transformer Differential Protection Using Principal Component Analysis,” IEEE Transactions on Power Delivery, Vol. 23, No.1, 2005, pp. 67-72. doi:10.1109/TPWRD.2007.911149
- Z. P. Wang and X. Wang, “Inrush Current Recognition in Power Transformer Based on Modified Principal Component Analysis,” Power System Protection and Control, Vol. 39, No. 22, 2011, pp. 1-4.
- L. D. Wang and Z. C. Duan, “Mal-operation Analysis on Magnetic Inrush Current of Power Transformer,” Power System Protection and Control, Vol. 38, No. 10, 2010, pp. 138-140.
- H. C. Shu and X. F. Sun, “Wye-delta Current Transform Effect on Sympathetic Inrush Transfer,” Journal of Electric Power Science and Technology, Vol. 23, No. 4, 2008, pp. 33-37.
- X. F. Sun and H. C. Shu, “Effect of CT Transient Saturation on Transfer of Sympathetic Inrush,” Electric Power Automation Equipment, Vol. 29, No. 1, 2009, pp. 83-88.
- W. J. Wang, “The Applications of Generator and Transformer Relay Protection,” China Electric Power Press, Beijing, 1998.
- X. J. Ge, “Comparison and Calibration of Two Kinds of Transformer Differential Protection,” Huadian Technology, Vol. 33, No. 10, 2011, pp. 51-53.
- S. L. Chen, H. Y. Li, Y. Qiao, ect, “RCS-978 Digital Transformer Protection Set,” Automation of Electric Power Systems, Vol. 24, No. 22, 2000, pp. 752-55.
- X. L. Deng and S. M. Liu, “Comparison of Two Current Compensation Methods in Transformer Protection,” Relay, Vol. 32, No. 13, 2004, pp. 20-24.
- Z. C. Liu, “Analysis of Magnetizing Inrush Current of Three-Phase Transformer and the Differential Protection Scheme,” Automation of Electric Power Systems, Vol. 30, No. 10, 2006, pp. 58-60.