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Device for measuring voltage transformers protection from ferroresonance processes in network with isolated neutral point

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Category: Electrical engineering

Last Updated on Thursday, 13 November 2014 10:53

Published on Thursday, 13 November 2014 10:53

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Authors:

Yu.L. Sayenko, Dr. Sci. (Tech.), Professor, State Higher Educational Institution “Pryazovskyi State Technical University”, Professor of the Department of Electrification of Industrial Enterprises, Mariupol, Ukraine.

V.V. Nesterovych, Cand. Sci.(Tech.), Associate Professor, State Higher Educational Institution “Pryazovskyi State Technical University”, Senior Lecturer of the Department of Electrification of Industrial Enterprises, Mariupol, Ukraine

A.S. Popov, Cand. Sci.(Tech.), State Higher Educational Institution “Pryazovskyi State Technical University”, Assistant Lecturer of the Department of Electrification of Industrial Enterprises, Mariupol, Ukraine

Abstract:

Purpose. Analysis of the operating principles of known protection devices for ferroresonance phenomena in networks with isolated neutral point. Identifying the features of the transient ferroresonance processes. Development of the algorithm and protective device for voltage transformers against ferroresonance processes, validation and testing performance of the proposed solutions.

Methodology. Mathematical model of electrical networks with isolated neutral was developed. The processes of ferroresonance phenomena and single-phase earth arc fault were simulated. Physical modeling techniques were used in evaluating the efficiency of protection devices against ferroresonance phenomena. Experimental methods were used in determining the parameters of voltage transformers necessary for mathematical modeling.

Findings. The analysis of the operating principle of widely known protection devices against ferroresonance phenomena was performed. It was found that in the single-phase arc ground fault mode false functioning of protection devices against ferroresonance is possible. Due to the mathematical modeling of transients frequency range of the ferroresonance oscillations was received. A method of identification the ferroresonance mode based on the spectral analysis of voltage 3u₀ and method of identification single-phase arc ground fault mode based on calculating the derivative voltage 3u₀ were proposed. The correctness and functionality of the proposed algorithms were verified by means of the test signals to input of protection devices.

Originality. Scientifically proved The method of the ferroresonance mode identification in network with isolated neutral point was scientifically proved, it is different from the known one by filtering of 3u₀voltage (Fourier analysis is used instead of the band-stop filter) that allows more accurately detect the type of the transient. The method of identification of single-phase arc ground fault mode was improved. This method is based on computing the derivative of the 3u₀ voltage and cooperation with set point that allows to prevent false function of protection devices at the single-phase arc ground fault mode.

Practical value. Protection algorithm of measuring voltage transformers against ferroresonance processeswas created. The protection device based on this algorithm was developed. The proposed methods of identification of transients may be used for protection against single-phase ground fault in networks with isolated neutral.

References:

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Zhyrakhivskyi, A.V., Yatseiko, A.Ya. and Masliak, R.Ya. (2009), “Operation modes of voltage transformer in electrical network with isolated neutral point”, Electroinform, no. 1, pp. 8–11.

2. Tsao, T. and Ning, C. (2006), “Analysis of ferroresonant overvoltages at Maanshan Nuclear Power Station in Taiwan”, IEEE Transactions on Power Delivery,Vol. 21, no. 3, pp. 1006–1012.

3. KMB systems, “Smart load to reduce ferroresonance”, available at: http://www.kmb.cz/in dex.php/en/other/afr-transf-protection (accessed November 2, 2013).

4. Wojciech, P., Florkowski, M., Fulczyk, M., and Mahonen, P. (2007), “Mitigating ferroresonance in voltage transformers in ungrounded MV networks”, IEEE Transactions on Power Delivery,Vol. 22, no. 4, pp. 2362–2369.

5. Повышение надежности в работе измерительных трансформаторов напряжения в сетях с изолированной нейтралью [Електронний ресурс]: официальный сайт запорожского завода высоковольтной аппаратуры – Режим доступа: http://www.zva.zp.ua /doc/ archivedoc/common/Reliability.pdf.

The official site of Zaporozhye Plant of High Voltage Equipment, “Increasing the reliability in the measuring voltage transformers in networks with isolated neutral point” available at: http://www.zva.zp.ua/doc/archivedoc/ common/Reliability.pdf (accessed November 2, 2013).

6. Aghazadeh, R., Sanaye-Pasand, M. (2004), “Damping of capacitive voltage substations ferroresonance using a suitable RLC filter”, IEE Proceeding Generation, Transmission & Distribution, Vol. 151, no. 6, pp. 721–727.

7. Braun, D., Delfanti, M., Palazzo, M. and Zich, K. (2012), “Harmonic distortion in power stations due to ferroresonance”, Proceedings of Asia-Pacific International Symposium on Electromagnetic Compatibility, May 21-24, 2012, Singapore, pp. 101–104.

8. Serhat, S., Tahir, C., and Sezai, T. (2012), “Spectral and statistical analysis for ferroresonance phenomenon in electric power systems”, Electrical Engineering, Vol. 94, issue 2, pp. 117–124.

9. Kizilkay, M., La Seta, P. (2005), “Digital simulation of fault arcs in medium-voltage distribution networks”, Proceedings from 15th Power Systems Computation Conference, August 22-26, 2005 Liège, Belgium, Session 36, Paper 3, рр. 1–7.

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