Transitory Regimes and Their Effects on the Insulation of High Power Transformers

Marian Duta; Maria Cristina Nitu; Marcel Nicola

doi:doi:10.11648/j.ajece.20200402.16

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Transitory Regimes and Their Effects on the Insulation of High Power Transformers

Marian Duta, Maria Cristina Nitu, Marcel Nicola

Published in American Journal of Electrical and Computer Engineering (Volume 4, Issue 2)

Received: 6 November 2020 Accepted: 18 November 2020 Published: 4 December 2020

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Abstract

Transformers are the most important pieces of equipment in the electricity transmission and distribution system. Their importance derives both from their high cost and from the fact that they ensure a proper operation of the national power system. The transitory regimes generated during the operation of transformers, such as the overvoltage caused by the lightning impulse and the transient currents when wiring the transformers result in mechanical stress, thermal stress and electrical stress in transformers. These stresses lead to the aging of the insulation system, to avoid possible damage or even the decommissioning of transformers, this paper presents analytical methods for determining the overvoltage transmitted between the windings of transformers due to the lightning impulse and the transient currents that occur when connecting the transformers. The studies were performed on two high power transformers: TTOS-OFAF of 40 MVA, 123 6.3 kV was used to determine the overvoltages that propagate at the windings of the transformer subjected to lightning impulse, and on TTOS-OFAF of 15 MVA, 10.5 / 6.3 kV was performed the study on the effects of the appearance of the connection current on the transformer insulation. The studied phenomena can have a negative impact on the transformer operation.. The results obtained have been validated by laboratory tests, and they can be used to determine the measures to be taken in order to avoid possible damages as of the time of the transformer implementation in the system.

Published in	American Journal of Electrical and Computer Engineering (Volume 4, Issue 2)
DOI	10.11648/j.ajece.20200402.16
Page(s)	72-80
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2020. Published by Science Publishing Group

Keywords

Overvoltage, Lightning Impulse, Inrush Current, Power Transformer, Insulation

References

[1]	Condition assessment of power transformers, in Cigré brochure 761, pp. 1–163, March 2019.
[2]	S. Jazebi, F. de León and N. Wu, "Enhanced Analytical Method for the Calculation of the Maximum Inrush Currents of Single-Phase Power Transformers," in IEEE Transactions on Power Delivery, vol. 30, no. 6, pp. 2590-2599, Dec. 2015.
[3]	Q. Guo, J. Wang, F. Zheng, G. Du, L. Zhu and J. Guo, "An Application of Inrush Current Suppression Technology Based on CNN in Switching Operation of High-voltage Built-in High-impedance Transformer," 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia), Singapore, 2018, pp. 511-516.
[4]	P. C. Y. Ling and A. Basak, "Investigation of magnetizing inrush current in a single-phase transformer," in IEEE Transactions on Magnetics, vol. 24, no. 6, pp. 3217-3222, Nov. 1988.
[5]	S. De and A. De, "Low cost surge voltage linearization methods for small rating power transformers," 2017 IEEE Calcutta Conference (CALCON), Kolkata, 2017, pp. 69-73.
[6]	Y. Zhou et al., "A Model Considering Deep Saturation of the Iron Core for 10 kV Potential Transformers," 2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE), ATHENS, Greece, 2018, pp. 1-4,
[7]	Zhong Yuan Zhang, Xin Ge, Zeng Chao Wang, "Research on Nonlinear Modeling for Power Transformer over Wide Frequency Range", Applied Mechanics and Materials, vol. 446-447, pp. 832, 2013.
[8]	S. V. Kulkarni, S. A. Khaparde, "Transformer Engineering: Design and Practice", Marcel Dekker, 2004.
[9]	I. Gheorghiu, A. Fransua, "Maşini electrice", vol. II. Editura Academiei Republicii Socialiste Romania, 1970.
[10]	Maria Cristina Niţu, Marian Duţă, "Calculation of Surges Transmitted Between Transformer Windings Using the Coupled Circuit Model", Proceedings of the International Conference on Applied and Theoretical Electricity (ICATE), Craiova, Romania, 4-6 October, 2018, pp. 1-6.
[11]	C. M. Arturi, “Transient Simulation and Analysis of a Five-Limb Step-Up Transformer Following and Out-of-Phase Synchronization”, IEEE Transactions on Power Delivery, Vol. 6, No. 1, January 1991, pp. 196-207.
[12]	P. I. Fegerstad, T. Henriksen, "Inductance for the Calculation of Transient Oscillation in Transformers", In: IEEE Transactions on Power Apparatus and Systems, vol. PAS-93, pp. 510-517, March/April 1974.
[13]	***IEC 60076-1: 2011-Power Transformer. Part. 1-General.
[14]	***IEC 60076-3: 2013-Power Transformer. Part. 3-Insulation levels, dielectric tests and external clearances in air.
[15]	Maria-Cristina Niţu, Claudiu-Ionel Nicola, Marcel Nicola, Marian Duţă, "Determination of Inrush Current to High Power Transformers using the LabVIEW Environment", Journal of Mechanical Engineering and Automation, Vol. 7, No. 2, 2017, pp. 46-52, USA.
[16]	Maria Cristina NIŢU, Marian DUŢĂ, Claudiu-Ionel NICOLA, "Predetermining the size of inrush current in power transformers coupling using LabVIEW", Proceedings of International Conference on Hydraulics and Pneumatics HERVEX – 22nd edition, Băile Govora, 9-11 November 2016, pp. 271-279.
[17]	Michael Streuer, Klaus Fröhlich, "The Impact off Inrush Currents on the Mechanical Stress of High Voltage Power Transformer Coils", In: IEEE Transactions on Power Delivery, vol. 17, No. 1, pp. 155-160, Ianuary 2002.
[18]	Yu Cui, Sami G. Abdulsalam, Shiuming Chen, Wilsun Xu, “A sequential phase energization technique for transformer inrush current reduction- Part I: Simulation and experimental results”, IEEE Trans. on Power Delivery, vol. 20, no. 2, pp. 943-949, April 2005.
[19]	Wilsun Xu, Sami G. Abdulsalam, Yu Cui, Xian Liu, “A sequential phase energization technique for transformer inrush current reduction- Part II- Theoretical analysis and design guide”, IEEE Trans. on Power Delivery, vol. 20, no. 2, pp. 950-957, April 2005.
[20]	Wilsun Xu, Sami G. Abdulsalam, “A sequential phase energization method for transformer inrush current reduction- transient performance and practical considerations”, IEEE Trans. on Power Delivery, vol. 22, no. 1, pp. 208-216, January 2007.
[21]	M. G. Vanti, S. L. Bertoli, S. H. Cabral, A. G. Gerent, P. Kuo-Peng, “Semianalytic solution for a simple model of inrush currents in transformers”, IEEE Trans. on Magnetics, vol. 44, no. 6, pp. 1270-1273, June 2008.
[22]	Maria Cristina NIŢU, V. Voicu, M. Duţă, P.-M. Nicolae, "Ensuring the Security of the Energy System by Predetermining the Size of Inrush Current at Power Transformers Coupling ", In Proc. of 16th - International Conference on Computer as a Tool- EUROCON, Salamanca, Spania, pp. 1-4, September 2015.
[23]	Hong, L. Haifeng, L. Hua, Z. Jiran, T. Haiguo and Z. Zhidan, "Waveform Complexity Analysis of Differential Current Signal to Detect Magnetizing Inrush in Power Transformer," 2017 9th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA), Changsha, 2017, pp. 120-123.
[24]	A. YAHIOU, A. BAYADI and B. BABES, "Point on Voltage Wave Switching for Sympathetic Inrush Current Reduction.," 2018 International Conference on Applied Smart Systems (ICASS), Medea, Algeria, 2018, pp. 1-4.
[25]	S. S. H. Bukhari, M. Gul and F. A. Chachar, "A Series Voltage Sag Compensator with Reduced Magnitude of Transformer Inrush Current," 2018 IEEE 4th Southern Power Electronics Conference (SPEC), Singapore, Singapore, 2018, pp. 1-4.

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APA Style

Marian Duta, Maria Cristina Nitu, Marcel Nicola. (2020). Transitory Regimes and Their Effects on the Insulation of High Power Transformers. American Journal of Electrical and Computer Engineering, 4(2), 72-80. https://doi.org/10.11648/j.ajece.20200402.16

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ACS Style

Marian Duta; Maria Cristina Nitu; Marcel Nicola. Transitory Regimes and Their Effects on the Insulation of High Power Transformers. Am. J. Electr. Comput. Eng. 2020, 4(2), 72-80. doi: 10.11648/j.ajece.20200402.16

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AMA Style

Marian Duta, Maria Cristina Nitu, Marcel Nicola. Transitory Regimes and Their Effects on the Insulation of High Power Transformers. Am J Electr Comput Eng. 2020;4(2):72-80. doi: 10.11648/j.ajece.20200402.16

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@article{10.11648/j.ajece.20200402.16,
  author = {Marian Duta and Maria Cristina Nitu and Marcel Nicola},
  title = {Transitory Regimes and Their Effects on the Insulation of High Power Transformers},
  journal = {American Journal of Electrical and Computer Engineering},
  volume = {4},
  number = {2},
  pages = {72-80},
  doi = {10.11648/j.ajece.20200402.16},
  url = {https://doi.org/10.11648/j.ajece.20200402.16},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajece.20200402.16},
  abstract = {Transformers are the most important pieces of equipment in the electricity transmission and distribution system. Their importance derives both from their high cost and from the fact that they ensure a proper operation of the national power system. The transitory regimes generated during the operation of transformers, such as the overvoltage caused by the lightning impulse and the transient currents when wiring the transformers result in mechanical stress, thermal stress and electrical stress in transformers. These stresses lead to the aging of the insulation system, to avoid possible damage or even the decommissioning of transformers, this paper presents analytical methods for determining the overvoltage transmitted between the windings of transformers due to the lightning impulse and the transient currents that occur when connecting the transformers. The studies were performed on two high power transformers: TTOS-OFAF of 40 MVA, 123 6.3 kV was used to determine the overvoltages that propagate at the windings of the transformer subjected to lightning impulse, and on TTOS-OFAF of 15 MVA, 10.5 / 6.3 kV was performed the study on the effects of the appearance of the connection current on the transformer insulation. The studied phenomena can have a negative impact on the transformer operation.. The results obtained have been validated by laboratory tests, and they can be used to determine the measures to be taken in order to avoid possible damages as of the time of the transformer implementation in the system.},
 year = {2020}
}

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TY  - JOUR
T1  - Transitory Regimes and Their Effects on the Insulation of High Power Transformers
AU  - Marian Duta
AU  - Maria Cristina Nitu
AU  - Marcel Nicola
Y1  - 2020/12/04
PY  - 2020
N1  - https://doi.org/10.11648/j.ajece.20200402.16
DO  - 10.11648/j.ajece.20200402.16
T2  - American Journal of Electrical and Computer Engineering
JF  - American Journal of Electrical and Computer Engineering
JO  - American Journal of Electrical and Computer Engineering
SP  - 72
EP  - 80
PB  - Science Publishing Group
SN  - 2640-0502
UR  - https://doi.org/10.11648/j.ajece.20200402.16
AB  - Transformers are the most important pieces of equipment in the electricity transmission and distribution system. Their importance derives both from their high cost and from the fact that they ensure a proper operation of the national power system. The transitory regimes generated during the operation of transformers, such as the overvoltage caused by the lightning impulse and the transient currents when wiring the transformers result in mechanical stress, thermal stress and electrical stress in transformers. These stresses lead to the aging of the insulation system, to avoid possible damage or even the decommissioning of transformers, this paper presents analytical methods for determining the overvoltage transmitted between the windings of transformers due to the lightning impulse and the transient currents that occur when connecting the transformers. The studies were performed on two high power transformers: TTOS-OFAF of 40 MVA, 123 6.3 kV was used to determine the overvoltages that propagate at the windings of the transformer subjected to lightning impulse, and on TTOS-OFAF of 15 MVA, 10.5 / 6.3 kV was performed the study on the effects of the appearance of the connection current on the transformer insulation. The studied phenomena can have a negative impact on the transformer operation.. The results obtained have been validated by laboratory tests, and they can be used to determine the measures to be taken in order to avoid possible damages as of the time of the transformer implementation in the system.
VL  - 4
IS  - 2
ER  -

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Author Information

Marian Duta

Research and Development Division/National Institute for Research Development and Testing in Electrical Engineering – ICMET, Craiova, Romania
Maria Cristina Nitu

Research and Development Division/National Institute for Research Development and Testing in Electrical Engineering – ICMET, Craiova, Romania
Marcel Nicola

Research and Development Division/National Institute for Research Development and Testing in Electrical Engineering – ICMET, Craiova, Romania

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APA Style

Marian Duta, Maria Cristina Nitu, Marcel Nicola. (2020). Transitory Regimes and Their Effects on the Insulation of High Power Transformers. American Journal of Electrical and Computer Engineering, 4(2), 72-80. https://doi.org/10.11648/j.ajece.20200402.16

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ACS Style

Marian Duta; Maria Cristina Nitu; Marcel Nicola. Transitory Regimes and Their Effects on the Insulation of High Power Transformers. Am. J. Electr. Comput. Eng. 2020, 4(2), 72-80. doi: 10.11648/j.ajece.20200402.16

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AMA Style

Marian Duta, Maria Cristina Nitu, Marcel Nicola. Transitory Regimes and Their Effects on the Insulation of High Power Transformers. Am J Electr Comput Eng. 2020;4(2):72-80. doi: 10.11648/j.ajece.20200402.16

Copy | Download

@article{10.11648/j.ajece.20200402.16,
  author = {Marian Duta and Maria Cristina Nitu and Marcel Nicola},
  title = {Transitory Regimes and Their Effects on the Insulation of High Power Transformers},
  journal = {American Journal of Electrical and Computer Engineering},
  volume = {4},
  number = {2},
  pages = {72-80},
  doi = {10.11648/j.ajece.20200402.16},
  url = {https://doi.org/10.11648/j.ajece.20200402.16},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajece.20200402.16},
  abstract = {Transformers are the most important pieces of equipment in the electricity transmission and distribution system. Their importance derives both from their high cost and from the fact that they ensure a proper operation of the national power system. The transitory regimes generated during the operation of transformers, such as the overvoltage caused by the lightning impulse and the transient currents when wiring the transformers result in mechanical stress, thermal stress and electrical stress in transformers. These stresses lead to the aging of the insulation system, to avoid possible damage or even the decommissioning of transformers, this paper presents analytical methods for determining the overvoltage transmitted between the windings of transformers due to the lightning impulse and the transient currents that occur when connecting the transformers. The studies were performed on two high power transformers: TTOS-OFAF of 40 MVA, 123 6.3 kV was used to determine the overvoltages that propagate at the windings of the transformer subjected to lightning impulse, and on TTOS-OFAF of 15 MVA, 10.5 / 6.3 kV was performed the study on the effects of the appearance of the connection current on the transformer insulation. The studied phenomena can have a negative impact on the transformer operation.. The results obtained have been validated by laboratory tests, and they can be used to determine the measures to be taken in order to avoid possible damages as of the time of the transformer implementation in the system.},
 year = {2020}
}

Copy | Download

TY  - JOUR
T1  - Transitory Regimes and Their Effects on the Insulation of High Power Transformers
AU  - Marian Duta
AU  - Maria Cristina Nitu
AU  - Marcel Nicola
Y1  - 2020/12/04
PY  - 2020
N1  - https://doi.org/10.11648/j.ajece.20200402.16
DO  - 10.11648/j.ajece.20200402.16
T2  - American Journal of Electrical and Computer Engineering
JF  - American Journal of Electrical and Computer Engineering
JO  - American Journal of Electrical and Computer Engineering
SP  - 72
EP  - 80
PB  - Science Publishing Group
SN  - 2640-0502
UR  - https://doi.org/10.11648/j.ajece.20200402.16
AB  - Transformers are the most important pieces of equipment in the electricity transmission and distribution system. Their importance derives both from their high cost and from the fact that they ensure a proper operation of the national power system. The transitory regimes generated during the operation of transformers, such as the overvoltage caused by the lightning impulse and the transient currents when wiring the transformers result in mechanical stress, thermal stress and electrical stress in transformers. These stresses lead to the aging of the insulation system, to avoid possible damage or even the decommissioning of transformers, this paper presents analytical methods for determining the overvoltage transmitted between the windings of transformers due to the lightning impulse and the transient currents that occur when connecting the transformers. The studies were performed on two high power transformers: TTOS-OFAF of 40 MVA, 123 6.3 kV was used to determine the overvoltages that propagate at the windings of the transformer subjected to lightning impulse, and on TTOS-OFAF of 15 MVA, 10.5 / 6.3 kV was performed the study on the effects of the appearance of the connection current on the transformer insulation. The studied phenomena can have a negative impact on the transformer operation.. The results obtained have been validated by laboratory tests, and they can be used to determine the measures to be taken in order to avoid possible damages as of the time of the transformer implementation in the system.
VL  - 4
IS  - 2
ER  -

Copy | Download