Moisture determination and degradation of solid insulation system of power transformers

Sumereder, Christof; Muhr, M.

doi:10.1109/elinsl.2010.5549775

Cited by 12 publications

(10 citation statements)

References 3 publications

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“…Variant factors such as high temperature, dissolved gases, humidity and frequent electrical discharge may accelerate the aging process [19,20], leading to uncertainty in comprehending the system, which is why statistical analyses have been extensively utilised to quantitatively describe the BD failure [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Enhanced breakdown performance of Anatase and Rutile titania based nano-oils

Katiyar

Dhar

Nandi

et al. 2016

IEEE Trans. Dielect. Electr. Insul.

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Nano-oils synthesized by dispersing dielectric nanostructures counter common intuition as such nano-oils possess substantially higher positive dielectric breakdown voltage with reduced streamer velocities than the base oils. Nano-oils comprising stable and dilute homogeneous dispersions of two forms of titanium (IV) oxide (TiO 2 ) nanoparticles (Anatase and Rutile) have been experimentally examined and observed to exhibit highly enhanced dielectric breakdown strength compared to conventional transformer oils. In-depth survey of literature yields that research on enhancing insulation properties of mineral oils by utilizing anatase and rutile titania nanoparticles is nought. The present study involves titania dispersed in two different grades of transformer oils, both with varied levels of thermal treatment, to obtain consistent and high degrees of enhancement in the breakdown strength, as well as high degrees of increment in the survival of the oils at elevated electrical stressing compared to the base oils, as obtained via detailed twin parameter Weibull distribution analysis of the experimental observations. The experimental results demonstrate augmentation in the breakdown strength ~79 % enhancement for Anatase and ~51% Rutile at relatively low concentrations of 0.1 wt. %. It is also observed that heat treatment of the nano-oils further enhances the dielectric breakdown performance. Additionally, further enhancements are observed at elevated operational temperatures. Detailed studies on the performance of the nano-oils in presence of variant quantities of moisture have also been put forward. Thegrossly different charging dynamics of dielectric nanoparticles localized within the oil has been proposed to be responsible for efficient electron trapping, leading to decrease in the positive streamer velocity and resulting in high dielectric breakdown voltage. The differences in the performance of anatase and rutile has been explained based on the electronic structure of the two and the affinity towards electron scavenging and the theory has been found to validate the experimental observations. The present study can find prime implications and promise in the field of dielectrics and liquid insulation of power electronics and electrical devices.

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Section: Introductionmentioning

confidence: 99%

Enhanced breakdown performance of Anatase and Rutile titania based nano-oils

Katiyar

Dhar

Nandi

et al. 2016

IEEE Trans. Dielect. Electr. Insul.

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“…The deterioration of cellulose material is powered by oxygen and water in LI with higher temperature. When the cellulose material migrates water content, water content level in the LI system gets increased, acid contents are formed and aging rate of cellulose insulation is accelerated [38]. In this work, Kraft paper is used as a SI for aging analysis and it's carried out in MO, RSO and SFO oil samples under selective conditions.…”

Section: Tensile Strengthmentioning

confidence: 99%

Failure analysis of transformer liquid — solid insulation system under selective environmental conditions using Weibull statistics method

Madavan¹,

Balaraman²

2016

Engineering Failure Analysis

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“…In Table 3, we present a color scale representing the association between the concentration rate of each gas and each type of failure occurring in the transformer. The table presented was constructed based on information collected from references [51][52][53]. The colors symbolize the different quantities of gases produced, with green being associated with small quantities (trace), yellow with medium quantities, and red with large quantities.…”

Section: Dissolved Gas-in-oil Analysismentioning

confidence: 99%

“…The average water content in it is almost constant under normal conditions over time, the opposite being true for oil. An example of the water content distribution in a 25 MVA transformer [53] is presented in Table 12, in which the above is illustrated. Water appears in the transformer through three distinct sources [54]:…”

Section: Model For Estimating Water Content In Insulation (Paper and ...mentioning

confidence: 99%

Large-Power Transformers: Time Now for Addressing Their Monitoring and Failure Investigation Techniques

2022

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Several review studies exist in the literature about monitoring, fault detection, and diagnosis of power transformers. However, they are general approaches in terms of power transformers. Some only focus on applying a specific class of techniques, but again, for general power transformers. Other reviews focus on applying different technologies such as fiber optics, thermal cameras, and vibration sensors, but all within the perspective of general power transformers. A significant question remains: among all types of power transformers, which specific techniques should be used, and why are they more adequate? What are the uncertainties that can decrease their precision? What about the balance, in terms of costs, associated with applying a certain technique and the return needed for a particular type of transformer? In this context, this paper is not only a literature review of well-known problems related to power transformers. Here, we do not just center on large power transformers (100 MVA or higher). Still, we describe a case study of a phase-shifting 1400 MVA-400 kV three-phase transformer that currently connects two European countries that began to show signs of abnormal operating conditions in 2012. In this way, the need to detect and identify anomalies in their initial stage of development for a possible preventive maintenance action is more than justified, which is essentially achieved with continuous monitoring models of the transformer, as concluded in this paper.

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Moisture determination and degradation of solid insulation system of power transformers

Cited by 12 publications

References 3 publications

Enhanced breakdown performance of Anatase and Rutile titania based nano-oils

Enhanced breakdown performance of Anatase and Rutile titania based nano-oils

Failure analysis of transformer liquid — solid insulation system under selective environmental conditions using Weibull statistics method

Large-Power Transformers: Time Now for Addressing Their Monitoring and Failure Investigation Techniques

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