Influence of temperature, moisture content and ageing on oil impregnated paper bushings insulation

Mikulecky, Antun; Štih, Željko

doi:10.1109/tdei.2013.6571464

Cited by 46 publications

(19 citation statements)

References 4 publications

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“…Dissipation factor is a method to identify the moisture content inside the dielectric insulation [2,16]. The complex permittivity * oil ε of transformer oil at a given frequency w (rad/s) and temperature T can be calculated as [9]:…”

Section: Detection Of Power Transformer Bushing Faults and Oilmentioning

confidence: 99%

“…Therefore, it is essential to adopt reliable diagnostic tools to precisely identify the health condition and to provide a proper maintenance action for in-service power transformers. The majority of worldwide transformers currently in service were installed prior to 1980 and as a result the bulk of the population is approaching or has already exceeded its design life [2][3][4][5][6][7][8]. This poses a significant risk for utilities and other power network stakeholders.…”

Section: Introductionmentioning

confidence: 99%

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Detection of power transformer bushing faults and oil degradation using frequency response analysis

Hashemnia

Abu-Siada

Islam

2016

IEEE Trans. Dielect. Electr. Insul.

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Section: Detection Of Power Transformer Bushing Faults and Oilmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection of power transformer bushing faults and oil degradation using frequency response analysis

Hashemnia

Abu-Siada

Islam

2016

IEEE Trans. Dielect. Electr. Insul.

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“…Step (1) to Step (4), and then +1 ( ) is obtained. (6) The sample entropy of this row data in the timefrequency matrix is obtained:…”

Section: Multidimensional Sample Entropy Parametersmentioning

confidence: 99%

“…A CIGRE international survey indicates that most of power transformers life is 30 years or so [4]. However, the majority of currently in-service power transformers were installed prior to 1980 and as a result the bulk of the population is approaching or has already exceeded its design life [5,6], which leads to a significant risk for power system stakeholders. Consequently, monitoring and diagnostic techniques are of important significance for improving operational reliability of the in-service power transformers.…”

Section: Introductionmentioning

confidence: 99%

Power Transformer Partial Discharge Fault Diagnosis Based on Multidimensional Feature Region

Jia

Xie

Wang

et al. 2016

Mathematical Problems in Engineering

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Effectively extracting power transformer partial discharge (PD) signals feature is of great significance for monitoring power transformer insulation condition. However, there has been lack of practical and effective extraction methods. For this reason, this paper suggests a novel method for the PD signal feature extraction based on multidimensional feature region. Firstly, in order to better describe differences in each frequency band of fault signals, empirical mode decomposition (EMD) and Hilbert-Huang transform (HHT) band-pass filter wave for raw signal is carried out. And the component of raw signals on each frequency band can be obtained. Secondly, the sample entropy value and the energy value of each frequency band component are calculated. Using the difference of each frequency band energy and complexity, signals feature region is established by the multidimensional energy parameters and the multidimensional sample entropy parameters to describe PD signals multidimensional feature information. Finally, partial discharge faults are classified by sphere-structured support vector machines algorithm. The result indicates that this method is able to identify and classify different partial discharge faults.

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“…[1][2][3][4][5][6][7][8][9][10] In addition, there are few more attempts made to expand the potential of FRA method to assess the condition of bushings and power cables. [10][11][12][13][14][15][16][17][18] This approach is reasonable as the presence of moisture and material degradation in the insulation geometry of transformers and bushings can be identified at very low frequencies (μHz till Hz) and at very high frequencies (few kHz till MHz, in some cases GHz). 3,4,[19][20][21][22][23][24] So, a simple comparison of the measured spectra (magnitude/phase response) with the respective "signature" data would reveal the insulation status of high voltage apparatus appropriately.…”

Section: Introductionmentioning

confidence: 99%

Nonconventional measurements on insulation materials high voltage bushings and power cables using frequency response analysis method

Arumugam

2020

Engineering Reports

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Power utilities desire an alternate noninvasive test method for assessing the diagnostic status of power apparatus. The primary reason is to minimize the economic constraints and ensure lifetime and reliability of power apparatus within shorter duration. In this context, frequency response analysis (FRA) method is increasingly recommended. The underlying principle of fault diagnosis using FRA method focuses on correlating the insulation condition to the changes in the magnitude and phase frequency response function. Existing practices validates the usage of FRA method in ascertaining the insulation integrity of transformers. Further attempts to expand the potential of FRA in method in determining the insulation status of power apparatus other than transformers, lack scientific and experimental evidence. To fill this gap, a research on using FRA method in assessing the insulation condition of high voltage bushings and power cables is initiated. Initially, test samples of insulation materials that are commonly used in bushings and cables are selected. The chosen samples are prepared in such a way that they represent common defect conditions that inflict premature material degradation and failures. These samples are grouped accordingly, placed on test cells, subjected to nonconventional FRA tests and their diagnostic status are respectively ascertained through comparative analysis. Following this, the pertinent findings are validated on actual bushings and power cables installed on a power transformer. In summary, the findings of this studies not only validate the usage of FRA method but provides the missing scientific and technical evidences and indices that could be used for diagnosing power apparatus. K E Y W O R D S bushings, cables, frequency response analysis, nonconventional, transformersThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Influence of temperature, moisture content and ageing on oil impregnated paper bushings insulation

Cited by 46 publications

References 4 publications

Detection of power transformer bushing faults and oil degradation using frequency response analysis

Detection of power transformer bushing faults and oil degradation using frequency response analysis

Power Transformer Partial Discharge Fault Diagnosis Based on Multidimensional Feature Region

Nonconventional measurements on insulation materials high voltage bushings and power cables using frequency response analysis method

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