Best practices for Dielectric Frequency Response measurements and analysis in real-world substation environment

Ohlen, M.; Werelius, P.; Cheng, Jialu; Sköldin, Joacim

doi:10.1109/cmd.2012.6416421

Cited by 8 publications

(6 citation statements)

References 3 publications

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“…For this purpose, analytical methods [4]- [7] or the numerical method proposed by U. Schmidt [3] can be used. WhereasĆ le 0+− is constant over the frequency range of our investigations,Ǵ le 0+− can change over the frequency [8]- [9]. But due to the fact thatǴ le 0+− is very much less than ωĆ le 0+− , G le 0+− as well as its frequency dependence can be neglected in cable models for harmonic calculations.…”

Section: E Frequency Dependence Of Cable Parametersmentioning

confidence: 74%

“…Afterwards, a numerical model with more details, especially for considering sheaths with wire screen, has been proposed by U. Schmidt [3]. The frequency dependence of the shunt admittance has been investigated in a variety of publications [8]- [9].…”

Section: Superscripts and Subscriptsmentioning

confidence: 99%

“…As already mentioned,Ý le 0+− is equal toÝ le . Therefore according to (9),Ý le 0+− is a diagonal matrix with the same diagonal entries. Neglecting the conductance of the inner insulation, the diagonal entries ofÝ le 0+− can be definded as jωĆ cs , whereĆ cs is the capacitance between the conductor and its own sheath.Ć cs has been calculated for the investigated cable system as 355.6 nF/km.…”

Section: Investigation Of Cable Behavior Over Frequency Dependinmentioning

confidence: 99%

See 2 more Smart Citations

Frequency dependent model of underground cables for harmonic calculations in frequency domain

Malekian

Schmidt

Hoshmeh

et al. 2014

2014 6th International Conference on Information Technology and Electrical Engineering (ICITEE)

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Modeling underground cables for application in harmonic calculations in frequency domain is discussed thoroughly in this paper. At first, equations and frequency-dependent parameters to describe the zero-, negative-, and positive-sequence cable impedances as well as the coupling between them are presented. Afterwards, the influence of cable arrangement on the zero-, negative-, and positive-sequence cable impedances is investigated over the frequency. In this regard, some representative cable systems with different arrangements are simulated. Physical interpretation of the simulation results for the different cable arrangements contributes to comprehend the behavior of underground cables over the frequency in zero, negative, and positive sequences. Subsequently, based on the findings, modeling underground cables for harmonic calculations in the frequency domain is discussed. Finally, the validity of the proposed model is proved by comparing the simulation results with measurements on a medium voltage cable.

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Section: E Frequency Dependence Of Cable Parametersmentioning

confidence: 74%

Section: Superscripts and Subscriptsmentioning

confidence: 99%

Section: Investigation Of Cable Behavior Over Frequency Dependinmentioning

confidence: 99%

See 1 more Smart Citation

Frequency dependent model of underground cables for harmonic calculations in frequency domain

Malekian

Schmidt

Hoshmeh

et al. 2014

2014 6th International Conference on Information Technology and Electrical Engineering (ICITEE)

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“…The XY model realizes the connection between laboratory data and field measurement data, and considers the influence of ambient temperature and winding geometry structure. It greatly simplifies the analyze of the dielectric response properties of oil-paper insulation, and has been widely used in transformer insulation diagnosis research [7][8][9]. Based on XY model, Refs [10,11] obtains the frequency spectrum of oil-immersed paper by the measured frequency dielectric spectrum of oil and oilpaper insulation, and applies it to the assessment of transformer insulation state.…”

Section: Introductionmentioning

confidence: 99%

Study on XY Model and Its Equivalent Circuit of Oil‐Paper Insulation

Tu¹,

Wang

et al. 2022

IEEJ Transactions Elec Engng

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The XY model of oil‐paper insulation connects the dielectric properties of oil, paper and oil‐paper system. Its equivalent circuit is the basis of the application of dielectric response technology in the state diagnosis of transformer oil‐paper insulation. To better apply the XY model to the study of the dielectric properties of oil‐paper insulation, the dielectric properties of the coaxial oil‐paper insulation system built in the laboratory, XY model and its equivalent circuits are compared. Then an improved circuit of XY model which can reflect the properties of the oil‐paper insulation more truly is proposed. The results show that there is no difference between the XY model and the coaxial model, and both can well characterize the oil‐paper insulation system. The two equivalent circuits of XY model, “Series to Parallel” circuit and “Parallel to Series” circuit, ignore the current tangential component and the electric field distortion in oil‐paper insulation, respectively, resulting in deviations from the XY model. By introducing a new branch C*XY, the improved circuit can reflect the tangential current and electric field distortion in oil‐paper insulation, which can be completely equivalent to XY model. In addition, there is a characteristic frequency point in the oil‐paper insulation system, where the dielectric loss factor tan δ of oil, paper and oil‐paper system are the same. There is no difference between the XY model and its two equivalent circuits at this point. The characteristic frequency is determined by the dielectric properties of oil and paper, and not affected by the insulation structure. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

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“…If the temperature of measured master curve is not equal to temperature of the tested transformer, the results of master curve must be transferred to temperature of the transformer under test. If the dielectric response is plotted on a logarithmic scale, temperature changes does not modify the overall shape of the curve, but the curve is displaced in the direction of the frequency axis [18]. The amount of frequency shift can be obtained from equation (9) [19]: (9) where: e is activation energy in electron-volt, k is the Boltzmann constant and T is the temperature in Kelvin.…”

Section: Determining the Master (Reference) Curvementioning

confidence: 99%

Condition assessment of transformer insulation using dielectric frequency response analysis by artificial bee colony algorithm

Bigdeli

Aghajanloo

2016

Archives of Electrical Engineering

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Transformers are one of the most important components of the power system. It is important to maintain and assess the condition. Transformer lifetime depends on the life of its insulation and insulation life is also strongly influenced by moisture in the insulation. Due to importance of this issue, in this paper a new method is introduced for determining the moisture content of the transformer insulation system using dielectric response analysis in the frequency domain based on artificial bee colony algorithm. First, the master curve of dielectric response is modeled. Then, using proposed method the master curve and the measured dielectric response curves are compared. By analyzing the results of the comparison, the moisture content of paper insulation, electrical conductivity of the insulating oil and dielectric model dimensions are determined. Finally, the proposed method is applied to several practical samples to demonstrate its capabilities compared with the well-known conventional method.

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Best practices for Dielectric Frequency Response measurements and analysis in real-world substation environment

Cited by 8 publications

References 3 publications

Frequency dependent model of underground cables for harmonic calculations in frequency domain

Frequency dependent model of underground cables for harmonic calculations in frequency domain

Study on XY Model and Its Equivalent Circuit of Oil‐Paper Insulation

Condition assessment of transformer insulation using dielectric frequency response analysis by artificial bee colony algorithm

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