Parameterization of Debye Model for Dielectrics Using Voltage Response Measurements and a Benchmark Problem

Mustafa, Ehtasham; Németh, Regina Mária; Afia, Ramy S. A.; Tamus, Zoltán Ádám

doi:10.3311/ppee.16399

Cited by 4 publications

(4 citation statements)

References 32 publications

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“…Hence in the present work, CDM is used to predict moisture and tanδ. Various performance parameters like %tanδ, %pm, Polarization index (PI), Dielectric adsorption ratio (DAR) have also been estimated from the CDM model [7]. These parameters indicate the insulation condition.…”

Section: Introductionmentioning

confidence: 99%

“…This situation cannot be avoided due to involvement of human factor. It is reported in [7] and [10] that when the polarization current measured just after rectifying the loose connection, the effect of residual dipole energy also affects the measured data. These residual dipoles energy in the system appears during the improper phase measurement under the application of charging voltage.…”

Section: Introductionmentioning

confidence: 99%

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Importance of Depolarization Current in the Diagnosis of Oil-Paper Insulation of Power Transformer

2023

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Recently, Polarization Depolarization current (PDC) measurement is widely accepted time domain spectroscopy-based method for assessing the insulation condition. Various performance parameters like Dissipation factor (%tanδ), Paper Moisture (%pm), Dielectric Adsorption Ratio (DAR), Polarization index (PI) etc. can be estimated by analyzing the PDC data. During field measurement various factors influences the recorded PDC data. As per existing literature, presence of low frequency noise, effect of temperature variation and influence of residual charge are common during field measurement. These factors significantly affect recorded polarization current and hence estimated performance parameters. Hence, analysis using recorded polarization current data may provide misleading information regarding insulation condition. Under such practical situation where polarization current is affected by above mentioned factors that generally observed during field measurement, depolarization current should be used for analysis of insulation condition. The depolarization current does not influence by such external factors. The present work shows the importance of depolarization current where polarization current is influenced by external low frequency noise and residual charge. The analysis firstly applied on sample prepared in the laboratory and then on data collected from real life in-situ transformers. The results obtained from the analysis shows that the data obtained from depolarization current is more reliable.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Importance of Depolarization Current in the Diagnosis of Oil-Paper Insulation of Power Transformer

2023

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“…Several non-destructive diagnostic testing methods have been used previously for High-Voltage (HV) insulation testing in power system equipment such as cables. The Return Voltage Measurement (RVM) and Voltage Response (VR) methods used for insulation diagnosis are some of the commonly used non-destructive testing methods [17,18]. In [11], Ghoneim stressed the role of furfurals along with other parameters in the classification of DP of the cellulose paper.…”

Section: Introductionmentioning

confidence: 99%

Classification of Cellulosic Insulation State Based on Smart Life Prediction Approach (SLPA)

et al. 2021

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The state of cellulosic solid kraft paper (CSKP) insulation, to a large extent, is an indication of a transformer’s health. It not only reflects the condition of transformer but also diagnose its residual life. The quantity of 2-furfuraldehyde (2-FAL), carbon dioxide (CO2), and carbon monoxide (CO) dissolved in the transformer oil are useful diagnostic indicators to predict the state of the CSKP insulation. In this work, the current physical state of the CSKP is determined with the help of easily measurable parameters, like temperature, moisture, and the aging time. Here, the degree of deterioration of CSKP insulation has been determined using an integrated insulation health assessment system. This technique integrates a two-stage system comprising of a neural network (NN) model followed by a Smart Life Prediction Approach (SLPA). A thermo-moisture-aging multi-layer feed-forward NN model has been developed to predict the concentrations of 2-FAL, CO2, and CO, which are further correlated to estimate the Degree of Polymerization (DP) values adopting an SLPA. The advantage of the proposed integrated system is that it provides an alternative means of paper health assessment based on Dissolved Gas Analysis (DGA) without estimating dissolved gas concentrations in oil, thereby avoiding the use of sophisticated measuring instruments. The optimal configuration of the NN model has been achieved at minimum iterations with an average cross-validation mean square error of 3.78 × 10−7. The proposed system thereby avoids destructive and offline measurement of DP and facilitates real-time condition monitoring of oil-immersed transformers. The test results of the developed system show considerable reliability in determining insulation health using easily measurable parameters. Furthermore, the system’s performance is compared with reported work and has been found to provide encouraging outcomes.

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“…Further improvements of absorption methods based on restored voltage are actively considered in the literature for the purpose of more adequate technical diagnostics of electrical insulation [11][12][13]. When using the method of restored voltage, as diagnostic parameters of insulation it is proposed to use the ratio of the maximum value of the restored voltage to the charging one, the initial rate of increase of the restored voltage, the time of reaching the maximum value of the restored voltage, the maximum value of the restored voltage, the coefficients of nonlinearity of the restored voltage, the time constant of the self-discharge, but in this article the method of recharged voltage will not be considered.…”

Section: Introductionmentioning

confidence: 99%

Reasoning of additional diagnostic parameters for electric insulation diagnostics by absorption methods

Kyrylenko¹,

Kyrylenko²,

Budko³

et al. 2021

Electrical Engineering & Electromechanics

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The aim of this work is to analyze the inadequacies of the diagnostic parameters, in particular the absorption and polarization coefficients, which are manifested in their integral character and dependence on the ratio of values of several elements of the equivalent scheme of insulation replacement. This article contains the results of theoretical investigation of the extremе nature of the absorption diagnostic parameters, which leads to unambiguity of the diagnostics procedure. The ways of partial adjustment of this unambiguity have been proposed. Methodology. To determine the extremality of the absorption coefficients depending on the absorption time, absorption capacity and resistance, as well as the leakage resistance, the usual method of investigating the functions was used, detailed calculations have been obtained by using MATLAB software. Results. Has been shown that the ambiguity of diagnostic results is caused by the contradiction of the integral character of the diagnostic parameters and the local character of the isolation failures, in particular breakdown, by ambiguous dependence of the diagnostic parameters on the values of the elements of the insulation replacement scheme and the extremal nature of the diagnostic parameters. Based on the general expression describing all currently used absorption coefficients, it is shown that they all have an extremum, the value of which depends on the parameters of the insulation substitution scheme and the time interval between the measurements of the absorption current. The dependence of the extreme value of the absorption and polarization coefficients on the parameters of the insulation substitution scheme has been established. Has been shown that to eliminate the ambiguity caused by the extremity of the absorption coefficients, it is necessary to introduce additional diagnostic parameters, such as the ratio of leakage resistance to absorption resistance, as well as the critical value of the absorption time constant. Originality. The detailed analysis of the reasons of ambiguity of electric insulation technical diagnostics by absorption methods has been carried out. A method for eliminating the ambiguity caused by the extremity of the absorption coefficients has been proposed. Practical significance. To eliminate the ambiguity caused by the extremity of the absorption coefficients, additional diagnostic parameters are proposed – the ratio of leakage resistance to the absorption resistance and critical values of the absorption time constant. The applying of these parameters with the absorption coefficients will more adequately assess the technical condition of insulation.

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Parameterization of Debye Model for Dielectrics Using Voltage Response Measurements and a Benchmark Problem

Cited by 4 publications

References 32 publications

Importance of Depolarization Current in the Diagnosis of Oil-Paper Insulation of Power Transformer

Importance of Depolarization Current in the Diagnosis of Oil-Paper Insulation of Power Transformer

Classification of Cellulosic Insulation State Based on Smart Life Prediction Approach (SLPA)

Reasoning of additional diagnostic parameters for electric insulation diagnostics by absorption methods

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