Analysis of Air-Tight High-Voltage Bushing Insulation Parameter Dynamics under Various Conditions during Long-term Operation

Shutenko, Оleg; Zagaynova, Alexandra; Serdyukova, Galina

doi:10.1109/ukrcon.2019.8879896

Cited by 7 publications

(2 citation statements)

References 8 publications

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“…Тобто фактично перевірити значущість впливу відмінностей в умовах експлуатації на значення показників масла. Як показано в [55][56][57] для перевірки впливу двох чинників доволі ефективно може бути використана модель двофакторного перехресного дисперсійного аналізу.…”

Section: аналіз публікаційunclassified

Analysis of the influence of service life on the value of oil indicators in 330 kV autotransformers

Ponomarenko

2023

EREE

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The results of two-factor crossed dispersion analysis of the influence of duration and operating conditions on the values of transformer oils in the tanks of 330 kV autotransformers are presented. On the basis of analysis of known mathematical models of oxidation processes of transformer oils on the basis of oxygen absorption, it was concluded that there is a significant influence of oxidation duration on the amount of absorbed oxygen, and, consequently, on the values of indicators of oils. To verify the conclusions made, the results of periodic tests of transformer oils condition for 49 autotransformers of 330 kV voltage were used. The total volume of the analysed sample amounted to 3654 values for 6 indicators of oils. Before the direct performance of the analysis, the initial data array was subjected to two-stage statistical processing, the purpose of which was to remove stationary and distorted by the sign of the angular coefficient of the regression model time series of oil indicators, with the subsequent formation of data arrays with a close rate of drift of indicators in time. The solution of the problem of the first stage was carried out on the basis of testing the statistical hypothesis of equality to zero of the angular coefficient of the linear regression of the oil indicator on the duration of operation. To solve the problem of the second stage, the criterion of maximum correlation ratio was used, which allowed to form data arrays with a close rate of drift of indicators in time, in conditions of either complete or partial absence of a priori information about the modes of operation of equipment of electric networks. Since for many indicators the presence of areas of intersection between the values of different data sets was revealed, along with testing the hypothesis about the influence of the duration of operation on the values of oil indicators, the hypothesis about the significance of differences between the values of indicators from different data sets was tested. For this purpose the model of two-factor crossed variance analysis was used. According to the results of the analysis it was found that there was a significant influence of the duration of operation on the values of oil indicators. In addition, significant differences between the values of indicators from different data sets, as well as non-additivity of the effects of changing the levels of factors, that is the effect of changing the level of exposure to one factor leads to a change in the effect of the level of exposure to another factor. The obtained results allow us to develop models for early diagnosis of transformer oil condition using variation boundaries of indicators, as well as to predict and manage the residual life of transformer oil.

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Section: аналіз публікаційunclassified

Analysis of the influence of service life on the value of oil indicators in 330 kV autotransformers

Ponomarenko

2023

EREE

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“…Слід зазначити, що використання лінійних моделей для аналізу залежностей показників масла від тривалості експлуатації є допущенням, оскільки результати досліджень, наведені в роботах [1,32,33], свідчать про наявність нелінійних ділянок в залежностях показників. Однак, результати, наведені в роботах [34,35] свідчать про те, що наявність нелінійностей в залежностях показників ізоляції різного обладнання, не робить істотного впливу на висновки про наявність або відсутність відмінностей в інтенсивності процесів старіння ізоляції.…”

Section: постановкаunclassified

Comparative analysis of oil ageing intensity in 110 kV transformers and 330 kV autotransformers

Ponomarenko

2021

Bull. Nat. Tech. Univ. "KhPI". Ser.: Energy: Reliab. Energy Eff

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The results of transformer oil ageing intensity analysis in 110 kV transformers and 330 kV autotransformers are presented. Using a mathematical model of variance linear regression analysis (covariance analysis model), applied to the results of periodic tests on 231 transformers of 110 kV and 49 autotransformers of 330 kV, several statistical hypotheses have been tested to estimate the intensity of drift of oil indicators during long-term operation of transformers. The following hypotheses were tested as statistical hypotheses: the hypothesis of a significant systematic drift in the values of oils during long-term operation, which allows assessing the presence of transformer oil ageing processes. The hypothesis of equality of partial angular coefficients for regression models based on test results for each of the oil in individual transformers (regression lines are parallel), which allows estimating the differences in the ageing intensity of oils in individual transformers. The hypothesis that the group averages lie on a straight line, that is, the drift of the oil in the different transformers occurs at the same rate. The hypothesis of equality of partial free terms for regression models based on test results for each of the oil indicators in individual transformers, which allows assessing the presence of differences in the values of oil indicators at the time of commissioning of transformers, that is, the actual presence of differences in the quality of the poured oil. The results of the analysis for both 110 kV transformers and 330 kV autotransformers showed not only an additive and multiplicative bias between individual series of oil parameters, but also a significant systematic component, indicating the aging of transformer oils in the analysed transformers. It was found that the intensity of drift of oil indicators in 110 kV transformers and in 330 kV autotransformers significantly differs, which should be taken into account when building models for the early recognition of the condition of transformer oils by the results of periodic tests.

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Informational and Analytical System for Diagnostics of the Electric Power Equipment Condition

Shutenko

Kulyk

Ponomarenko

2020

2020 IEEE 7th International Conference on Energy Smart Systems (ESS)

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Analysis of Air-Tight High-Voltage Bushing Insulation Parameter Dynamics under Various Conditions during Long-term Operation

Cited by 7 publications

References 8 publications

Analysis of the influence of service life on the value of oil indicators in 330 kV autotransformers

Analysis of the influence of service life on the value of oil indicators in 330 kV autotransformers

Comparative analysis of oil ageing intensity in 110 kV transformers and 330 kV autotransformers

Informational and Analytical System for Diagnostics of the Electric Power Equipment Condition

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