A Novel Wavelet Based Method for Improvement of Power Transformer Differential Relay against Magnetizing Inrush Current and CT Saturation
Subject Areas : electrical and computer engineering
A.
Rahmati
1
(University of Tehran)
M.
Sanaye-Pasand
2
(University of Tehran)
Keywords: CT saturationwavelet transformpower transformerinrush currentdifferential relay,
Abstract :
Differential protective relay serves as the main protection of transformers against faults in the windings for many years. Unremitting tries for more smart of this protection relay have been done by different creative manufactures and up to now different methods and inventions have been proposed for better operational of the differential relay. However, a differential protection for differential currents would be handicapped by difficulties due to several natural phenomena which are the cause of false differential currents and misoperate of the relay. Some of these phenomena, such as the inrush current and saturation of instrument current transformers, are the main concern in designing an efficient differential protection algorithm. This paper at first, proposes a new algorithm based on the Wavelet Transform (WT) to identify internal fault from magnetizing inrush in three phase power transformers. The internal faults can be accurately discriminated from inrush current less than a quarter a cycle after the disturbance. At following with definition of an index which it is extracted from the high frequencies by WT, the restrain current in bias-current characteristic of differential relay has been improved. Obtained results demonstrate that the proposed algorithm can provide the desired response and can be used as a very fast and accurate method.
[1] م. خدرزاده، ا. صفرنورالله، م. مرتجایي و م. ا. همداني گلشن، حفاظت سیستمهاي قدرت، چاپ اول، دانشگاه صنعت آب و برق، .١٣٨٢
[2] T. S. Sidhu, M. S. Sachdev, H. C. Wood, and M. Nagpal, "Design, implementation, and testing of a micro-processor- based high-speed relay for detecting transformer winding faults," IEEE Trans. Power Del., vol. 7, no. 1, pp. 108-117, Jan. 1992.
[3] P. Liu, O. P. Malik, C. Chen, G. S. Hope, and Y. Guo, "Improved operation of differential protection of power transformers for internal faults," IEEE Trans. Power Del., vol. 7, no. 4, pp. 1912-1919, Oct. 1992.
[4] K. Yabe, "Power differential method for discrimination between fault and magnetizing inrush current in transformers," IEEE Trans. Power Delivery, vol. 12, no. 3, pp. 1109-1117, Jul. 1997.
[5] T. S. Sidhu and M. S. Sachdev, "Online identification of magnetizing inrush and internal faults in three phase transformers," IEEE Trans. Power Delivery, vol. 7, no. 4, pp. 1885-1890, Oct. 1992.
[6] G. D. Rockefeller, "Fault protection with a digital computer," IEEE Trans. on Power Apparatus and Systems, vol. 88, no. 4, pp. 438-464, Apr. 1969.
[7] A. Giuliante and G. Clough, "Advances in the design of differential protection for power transformers," in Proc. Georgia Technical Protective Relaying Conf., pp. 1-12, Atlanta, Georgia, May 1991.
[8] P. Bastard, M. Meunier, and H. Regal, "Neural network based algorithm for power transformer differential relays," IEEE Processings Generation, Transmission, and Distribution, vol. 142, no. 4, pp. 386-392, Jul. 1995.
[9] M. V. Ribeiro, J. M. T. Romano, and C. A. Duqe, "An improved method for signal processing and compression in power quality evalution," IEEE Trans. on Power Delivery, vol. 19, no. 2, pp. 464-471, Apr. 2004.
[10] T. M. Lai, L. A. Snider, E. Lo, and D. Sutanto, "High - impedance fault detection using discrete wavelet transform and frequency range and RMS conversion," IEEE Trans. on. Power Delivery, vol. 20, no. 1, pp. 397-407, Jan. 2005.
[11] H. Mortazavi and H. Khorashadi-Zadeh, "A new inrush restraint algorithm for transformer differential relay using wavelet transform," in Int. Conf. on Power System Technology, Powercon’04, vol. 2, pp. 1705-1709, Singapore, Nov. 2004.
[12] S. A. Saleh and M. A. Rahman, "Modeling and protection of a three - phase power transformer using wavelet packet transform," IEEE Trans. on Power Delivery, vol. 20, no. 2, pp. 1273-1282, Apr. 2005.
[13] O. A. S. Youssef, "A wavelet - based technique for discrimination between faults and magnetizing inrush currents in transformers," IEEE Trans. Power Del., vol. 18, no. 1, pp. 170-176, Jan. 2003.
[14] A. Guzman, S. Zocholl, G. Benmouyal, and H. J. Altuve, "A current based solution for transformer differential protection - part I: problem statement," IEEE Trans. on Power Del., vol. 16, no. 4, pp. 485-491, Oct. 2001.
[15] G. Ziegler, Numerical Differential Protection: Principles, and Applications, Publicis Corporate Publishing, Erlangen, 2005.
[16] Application Manual of RET 521*2.3, Transf-ormer Protection Relay, ABB Company, 1MRK 504 021-UEN.
[17] S. D. Cho, Parameter Estimation for Transformer Modeling, Ph.D. Dissertation, Michigan Technological University, Dec. 2002.