Analysis of dielectric response measurements for condition assessment of oil-paper transformer insulation

Koch, M.; Prevost, Thomas

doi:10.1109/tdei.2012.6396947

Cited by 116 publications

(73 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Transformers, widely in the electric power transmission and transformation area, are regarded as one of the most important pieces of equipment [1,2]. Unfortunately, during their long operation period, the ageing of transformer insulation inevitably occurs due to the complicated operating conditions [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Study on Quantitative Correlations between the Ageing Condition of Transformer Cellulose Insulation and the Large Time Constant Obtained from the Extended Debye Model

et al. 2017

View full text Add to dashboard Cite

Polarization-depolarization current (PDC) measurements are now being used as a diagnosis tool to predict the ageing condition of transformer oil-paper insulation. Unfortunately, it is somewhat difficult to obtain the ageing condition of transformer cellulose insulation using the PDC technique due to the variation in transformer insulation geometry. In this literature, to quantify the ageing condition of transformer cellulose insulation using the PDC technique, we firstly designed a series of experiments under controlled laboratory conditions, and then obtained the branch parameters of an extended Debye model using the technique of curve fitting the PDC data. Finally, the ageing effect and water effect on the parameters of large time constant branches were systematically investigated. In the present paper, it is observed that there is a good exponential correlation between large time constants and degree of polymerization (DP). Therefore, the authors believe that the large time constants may be regard as a sensitive ageing indicator and the nice correlations might be utilized for the quantitative assessment of ageing condition in transformer cellulose insulation in the future due to the geometry independence of large time constants. In addition, it is found that the water in cellulose pressboards has a predominant effect on large time constants.

show abstract

Section: Introductionmentioning

confidence: 99%

“…It is believed that a suddenly occurring insulation failure in a transformer can be traced back to its insulation degradation/ageing. It is believed that insulation [2,12,13]. Moreover, the furan measurement technique is a practical method for quantitatively assessing transformer cellulose insulation ageing [11].…”

Section: Introductionmentioning

confidence: 99%

Study on Quantitative Correlations between the Ageing Condition of Transformer Cellulose Insulation and the Large Time Constant Obtained from the Extended Debye Model

et al. 2017

View full text Add to dashboard Cite

show abstract

“…With a reduction in the applied frequency, interfacial polarization is fully developed, leading to increasing polarization loss and an increment of ε". At the same time, ε 1 is increasing with the increase of the polarization intensity [28]. The complex correlations between polarization intensity and the speed of polarization result in the "deceleration zone" in a certain frequency band, which is determined by the measuring temperature, oil paper constituents, aging time, and moisture content [24,29].…”

Section: How Aging and Moisture Content Affect Tan δmentioning

confidence: 99%

“…The results of k Bi are shown in Figure 10, the fitting curve accords with a cubic polynomial, and the goodness of fit is one. The life loss of insulation aging caused by damp conditions is calculated by imitating Arrhenius law, which is used to evaluate accelerated aging caused by temperature [28]. First, according to the integral value of the tan δ in the characteristic interval, the equivalent aging stage of the insulation can be calculated by Equation (5) (moisture is not considered for accelerated aging).…”

Section: Aging and Moisture Characteristics Based On Tan δmentioning

confidence: 99%

Study of the Impact of Initial Moisture Content in Oil Impregnated Insulation Paper on Thermal Aging Rate of Condenser Bushing

et al. 2015

View full text Add to dashboard Cite

This paper studied the impact of moisture on the correlated characteristics of the condenser bushings oil-paper insulation system. The oil-impregnated paper samples underwent accelerated thermal aging at 130˝C after preparation at different initial moisture contents (1%, 3%, 5% and 7%). All the samples were extracted periodically for the measurement of the moisture content, the degree of polymerization (DP) and frequency domain dielectric spectroscopy (FDS). Next, the measurement results of samples were compared to the related research results of transformer oil-paper insulation, offering a theoretical basis of the parameter analysis. The obtained results show that the moisture fluctuation amplitude can reflect the different initial moisture contents of insulating paper and the mass ratio of oil and paper has little impact on the moisture content fluctuation pattern in oil-paper but has a great impact on moisture fluctuation amplitude; reduction of DP presents an accelerating trend with the increase of initial moisture content, and the aging rate of test samples is higher under low moisture content but lower under high moisture content compared to the insulation paper in transformers. Two obvious "deceleration zones" appeared in the dielectric spectrum with the decrease of frequency, and not only does the integral value of dielectric dissipation factor (tan δ) reflect the aging degree, but it reflects the moisture content in solid insulation. These types of research in this paper can be applied to evaluate the condition of humidified insulation and the aging state of solid insulation for condenser bushings.

show abstract

“…Moisture is a hazard to an insulation system in several ways: a) acceleration of the ageing of paper insulation, b) lowering the admissible hot spot temperature, c) PD inception becomes significant when the moisture in solid insulation is above 3%, d) reducing the dielectric strength of the insulation system [26,27]. Therefore, in order to maximise the lifetime and safety of transformers in operation through corrective maintenance actions, it is important to accurately estimate the Chapter 1 Introduction 5 | P a g e moisture content in a transformer insulation system using a reliable technique.…”

Section: Overviewmentioning

confidence: 99%

Condition monitoring of biodegradable oil filled transformer

Mudiyanselage¹,

Bandara²

View full text Add to dashboard Cite

Natural and synthetic ester insulating oils have higher fire points and excellent biodegradable characteristics. Therefore, in order to reduce the adverse environmental impact and to improve the fire safety of transformers, there is an increasing demand for natural and synthetic ester insulating liquids as a transformer insulating oil. However, present understanding on ageing behaviour of ester oil-paper composite insulation system and knowledge on application of existing condition monitoring tools for ester based insulation systems are inadequate. This impedes the cost effective and reliable field applications of ester insulating oils, particularly application of natural esters. To reduce this knowledge gap, series of controlled ageing experiments are performed in this research project to provide a better and comprehensive understanding on ageing behaviour of ester oil-paper insulation systems. Furthermore, applicability of existing chemical and electrical based condition monitoring techniques for ester oil-paper insulation systems is systematically investigated in this research project.In this thesis, ageing behaviour of dry pressboard insulation in mineral and three different ester insulating oils under simulated transformer operating environment is investigated. Moreover, the ageing behaviour of natural ester-pressboard composite insulation in moisture rich environment is also compared with that of mineral oil-pressboard system. Degree of polymerisation of pressboard samples measured at different ageing interval is used in this research to determine the ageing condition of pressboard. Moreover, applicability of oil related diagnostic parameters such as concentration of dissolved furanic compounds, acidity value, Dielectric Dissipation Factor (DDF), viscosity and colour to assess the degree of degradation of both ester and mineral insulating oils is thoroughly investigated in this research project. The potential of FTIR (Fourier Transform Infrared spectroscopy) techniques for characterising the degree of degradation of paper insulation is also discussed in this thesis. In addition, this thesis concentrates on characterisation of the charge dynamic in insulating oil through modelling of their dielectric responses.The comparison of gassing behaviour of ester and mineral insulating oils under two different low temperature faults and low energy electric discharge condition is also presented in this thesis.Dissolved Gas Analysis (DGA) results presented in this thesis depicts that faults gases detected in ester and mineral oil samples subjected to a similar fault are akin in type but quantitatively different. The quantity of fault gases produced in two different natural ester oils is also dissimilar.For example, soy-based natural ester produces a large quantity of ethane (C2H6) under low temperature overheating condition than sunflower oil based natural ester. Therefore, this research project investigates the applicability of well-established DGA interpretation schemes namely Duval II | P a g e triangle, IE...

show abstract

Analysis of dielectric response measurements for condition assessment of oil-paper transformer insulation

Cited by 116 publications

References 3 publications

Study on Quantitative Correlations between the Ageing Condition of Transformer Cellulose Insulation and the Large Time Constant Obtained from the Extended Debye Model

Study on Quantitative Correlations between the Ageing Condition of Transformer Cellulose Insulation and the Large Time Constant Obtained from the Extended Debye Model

Study of the Impact of Initial Moisture Content in Oil Impregnated Insulation Paper on Thermal Aging Rate of Condenser Bushing

Condition monitoring of biodegradable oil filled transformer

Contact Info

Product

Resources

About