Wide band modeling of large power transformer windings for very fast transient overvoltage (VFTO) analysis

Yang, Yu; Zanji, Wang

doi:10.1007/s11431-009-0240-z

Cited by 14 publications

(5 citation statements)

References 9 publications

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“…Substitute it into (16), and then elimination , we can obtain (17) It is shown that the attenuation factor is determined by , representing the dielectric loss and representing the resistance loss. Then, we can define the specific form of and as follows.…”

Section: B Fitting Formula Of Attenuation Factorsmentioning

confidence: 99%

“…Power transformers and other large electrical devices are vulnerable to the very fast transient overvoltage (VFTO) generated by the switching operations of vacuum circuit breakers in adjacent gas-insulated substations (GIS). Extremely nonuniform transient voltage distribution which could cause great harm to the insulation system might appear Many achievements have been published about the related modeling and computational methods [5]- [17]. However, there is still no effective method taking the transformer loss into consideration and only a few publications about determining the impact of frequency-dependent loss on the voltage distribution calculation in fast transient frequency range (within tens of megahertz).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Determining the Broadband Loss Characteristics of Power Transformer Based on Measured Transformer Network Functions and Vector Fitting Method

Zheng

Zanji

2013

IEEE Trans. Power Delivery

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A method is proposed in this paper to determine the frequency-dependent loss of power transformer for very fast transient simulation. The attenuation factors and the corresponding natural frequencies of the transformer at measurable range were extracted using measured power transformer network functions and the vector-fitting method (VFM). The approximate frequencydependent formula of attenuation factors was established by analyzing the theoretical transformer model. Then, the parameters in the formula were optimized by fitting the real part (attenuation factors) and imagine part (natural angular frequencies) of poles obtained by VFM. The time-domain simulation process can be divided into two steps. First, the lossless transformer transient response, which could be expressed as the sum of the natural frequency components, is obtained by solving the network differential equations. Second, the attenuation factors calculated by the approximate formula are added directly on the corresponding frequency components. By comparing with the measured results, it is shown that the proposed fitting formula for calculating the attenuation factors could improve the simulation accuracy in comparison with the existing methods.

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Section: B Fitting Formula Of Attenuation Factorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determining the Broadband Loss Characteristics of Power Transformer Based on Measured Transformer Network Functions and Vector Fitting Method

Zheng

Zanji

2013

IEEE Trans. Power Delivery

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“…Transformers are the most important equipment in the power station, whose damage could lead to serious consequences [1][2][3][4]. At present, there are many accidents occurred in the substation equipment, which contains a large number of unidentified insulation accident.…”

Section: Introductionmentioning

confidence: 99%

Research on Evaluation Method of Transient Overvoltage Hazard Based on S-Transform

Tian¹,

Wu²,

Li³

et al. 2017

Proceedings of the 2017 2nd International Symposium on Advances in Electrical, Electronics and Computer Engineering (ISAEECE 20

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In field operation, the transformer with good insulation design and insulation condition may failure caused by transient over-voltage. The accumulation of transient overvoltage reduces the reliability of transformer internal insulation without signs. Therefore, it is necessary to assess the over-voltage hazards on the transformer. In order to evaluate the transient damage of transformers in operation, the transient overvoltage evaluation method based on S transform is proposed in this paper. Firstly, a method based on traditional Fourier transform is introduced. Secondly, the defects of traditional Fourier transform are analyzed. Finally, a transient overvoltage evaluation based on S transform is proposed to overcome the shortcomings of traditional Fourier transform method.

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“…By means of the computer simulation tools to predict distribution of transient voltage in transformer winding is a major method to guide the insulation structure design with lots of papers [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] published. However, there are only scarce publications about the loss characteristics of the power transformers at the fast transient frequency range (about a few megahertz to tens of megahertz).…”

Section: Introductionmentioning

confidence: 99%

Study on broadband loss characteristics of oil-immersed papers for fast transient modeling of power transformer

Zheng

Zanji

2013

IEEE Trans. Dielect. Electr. Insul.

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In order to complete the broadband simulation model of power transformer, and establish a systematic and complete model for studying fast transient interaction between transformer and power system, the frequency dependent characteristics of dielectric losses in power transformer were investigated. Several typical insulation structures in power transformers were considered and measuring techniques determined to study the dielectric losses. Frequency dependent dielectric losses in the range of 10-10 7 Hz were measured by a dielectric spectroscopy analyzer produced by Novocontrol. The characteristics of insulating papers and pressboard measured in the air and after immersing in the mineral oil were compared. Based on the dielectric relaxation theory, the number of dielectric relaxation was determined according to the measured data, and four typical model functions were adopted to fit the data and the consistency of fitting by these functions were compared and physical explanations of fitting parameters were described. Finally, a quantitative description of frequency dependent characteristics of insulation losses was proposed for improving the transformer simulation model. . His research interests focuses on circuits and systems, dielectric response of transformer insulation, frequency dependent loss of power transformer and electromagnetic transient modeling and simulations.Zan-ji Wang (SM'01) received the B.S., M.S., and Ph.D. degrees in electrical engineering

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Wide band modeling of large power transformer windings for very fast transient overvoltage (VFTO) analysis

Cited by 14 publications

References 9 publications

Determining the Broadband Loss Characteristics of Power Transformer Based on Measured Transformer Network Functions and Vector Fitting Method

Determining the Broadband Loss Characteristics of Power Transformer Based on Measured Transformer Network Functions and Vector Fitting Method

Research on Evaluation Method of Transient Overvoltage Hazard Based on S-Transform

Study on broadband loss characteristics of oil-immersed papers for fast transient modeling of power transformer

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