EPE  Vol.5 No.4 B , July 2013
Research on the Reason for Transformer Differential Protection Mal-operation Caused by Sympathetic Inrush
Abstract: The paper is concerned with whether CT transient saturation, which caused by sympathetic inrush, is the direct reason for mal-operation of transformer differential relays. In order to analyze transforming characteristics of saturated CT, the gain of each harmonic current transforming from primary winding to secondary winding of transient saturation CT is calculated. Based on the fact that series sympathetic inrush is easier to lead differential relay mal-operation than parallel sympathetic inrush, the effect of CT saturation on differential relay in the case of both parallel sympathetic inrush and series sympathetic inrush are investigated respectively. Theory analysis and simulation show that higher harmonic will be transferred by saturated CT more easily than lower harmonic, and then the second harmonic proportion of CT secondary side is higher than that of CT primary side. Thus CT transient saturation itself is not essential reason for differential relay mal-operation. Parallel sympathetic inrush and series sympathetic inrush will lead to different location CT saturated. Parallel sympathetic inrush will lead to CT located system side saturated; second harmonic ratio of differential current increase and dead angle is large. Series sympathetic inrush will lead to CT located load side saturated; second harmonic ratio of differential current decrease and dead angle is small.
Cite this paper: X. Sun, H. Shu and J. Zhou, "Research on the Reason for Transformer Differential Protection Mal-operation Caused by Sympathetic Inrush," Energy and Power Engineering, Vol. 5 No. 4, 2013, pp. 1077-1082. doi: 10.4236/epe.2013.54B205.

[1]   G. B. Kumbhar and S. V. Kulkarni, “Analysis of Sympathetic Inrush Phenomena in Transformers Using Coupled Field-circuit Approach,” Proceedings 2007 IEEE Power Engineering Society General Meeting, PES, Tampa,24-28 June 2007, pp. 427-432.

[2]   J. Pontt, J. Rodriguez, J. S. Martin, and R. Aguilera, “Mitigation of Sympathetic Interaction between Power Transformers Fed by Long over Head Lines Caused by Inrush Transient Currents,” Industry Applications Conference,2007, 42nd IAS Annual Meeting, Conference Record of the 2007 IEEE, New Orleans, 23-27 September 2007, pp. 1360-1363, 2007.

[3]   A. MohdZin, Hana AbdullHalimand, S. P. Abdul Karim. “Sympathetic Inrush Current Phenomenon Analysis and Solution for a Power Transformer,”International Review on Modelling and Simulations (IREMOS), April 2011, pp. 601-607.

[4]   H. S. Bronzeado, P. B. Brogan and R. Yacamini, “Harmonic Analysis of Transient Currents during Sympathetic Interaction,” IEEE Transactions on Power Systems, Vol. 11, No. 4, 1996, pp. 2051- 2056. doi:10.1109/59.544684

[5]   Y. B. Zhou and L. Cao, “Inspection and Analysis of a Maloperation of Transformer Differential Protection and Its Preventive Measures,” Power Systems Technology, Vol.25, No. 20, 2001, pp. 71-74.

[6]   G. W. Yu, D. Q. Bi, Z. G. Wang and etc, “Phenomenon of Sympathetic Inrush and Analysis of an Example,” Automation of Electric Power Systems, Vol. 29, No. 6, 2005, pp.20-23.

[7]   D. J. Li, W. J. Wang and D. Q. Bi, “Analysis of Transient Saturation and Sympathetic Inrush of Transformers,” High Voltage Apparatus, Vol. 41, No.1, 2005, pp.12-15.

[8]   L. Wei, T. Zheng, G. G. Wang and etc, “Synthetic Analysis on the Causes of Mal-operation and Preventive Measures of Transformer Differential Protection,” Power System Protection and Control, Vol. 36, No. 19, 2008, pp.40-43.

[9]   J. H. Wang and J. Q. Li, “The Analysis of a Misoperation of Differential Protection of Transformer,” Hydropower and New Energy, Vol. 6, 2011, pp.32-34.

[10]   S. F. Huang, J. Gu, T. Zheng and etc, “Mal-operation of Transformer Differential Protection with Inner Bridge Connection and Counter measure,” High Voltage Engineering, Vol.37, No.12, 2011, pp.3099-3106.

[11]   D. Q. Bi, X. H. Wang, D. J. Li and etc, “Theory Analysis of the Sympathetic Inrush in Operating Transformers,” Automation of Electric Power System, Vol. 29, No.6, 2005, pp.1-8.

[12]   Y. B. Yuan, D. J. Li and Y. P. Lu, “Physical Mechanism of Sympathetic Inrush of Transformer and Its Influence on Differential Protection,” Automation of Electric Power Systems, Vol.29, No.6, 2005, pp.9-14.

[13]   T. Zheng and P. Zhao, “Analysis of Influence Factors of Sympathetic Inrush on Differential Protection and Its Solution,” Automation of Electric Power Systems, Vol.33, No. 3, 2009, pp.74-78.

[14]   X. S. Zhang and B. T. He, “Influence of Sympathetic Interaction between Transformers on Relay Protection,” Proceedings of the CSEE, Vol.26, No.14, 2006, pp. 12-17.

[15]   X. F. Sun, H. C. Shu and J. L. Yu, “Comparison of Sympathetic Inrush Influence on Differential Protection between Parallel and Series Transformers,” Electric Power Automation Equipment, Vol. 29, No.3, 2009, pp.36-41.

[16]   M. L. Jin, X. G. Yin and D. H. You, “Reason of Differential Protection Mal-operation Caused by Complex Sympathetic Inrush and Its Counter measure,” Proceedings of the CSEE, Vol. 31, No.1, 2011, pp. 86-72.