Application of Synthetic Ester for Drying Distribution Transformer Insulation—The Influence of Cellulose Thickness on Drying Efficiency

Przybyłek, Piotr; Morańda, H.; Mościcka-Grzesiak, H.; Szczęśniak, Dominika

doi:10.3390/en12203874

Cited by 13 publications

(9 citation statements)

References 37 publications

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“…In the earlier research, described in publication [11], the effect of cellulose sample thickness on the efficiency and dynamics of their drying with the use of synthetic ester was investigated. During the experiment 0.05, 0.5, 3.0, and 5.0 mm thickness samples were tested.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Model Studies on the Drying Efficiency of Transformer Cellulose Insulation Using Synthetic Ester

et al. 2020

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This paper presents the results of laboratory tests of cellulose insulation drying with the use of synthetic ester. The effectiveness of the drying process was investigated depending on the initial moisture of cellulose samples (2%, 3%, and 4%), ester temperature (55, 70, and 85 °C), initial moisture of the ester (70, 140, and 220 ppm), drying time (48, 96, and 168 h), and the weight ratio of cellulosic materials to ester (0.067 and 0.033). A large influence of temperature and time of drying on the efficiency of the drying process was found. This is important information due to the application of the results in the transformers drying procedure. The heating and drying ester unit should provide the highest possible temperature. For the assumed experiment conditions the initial moisture of the ester had little effect on the drying efficiency. An ester with a moisture content below 140 ppm can still be considered as meeting the requirements for drying cellulose with significant moisture. The weight ratio of cellulose products to ester has no major effect on drying efficiency during cellulose drying by circulating dry ester.

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Section: Introductionmentioning

confidence: 99%

Laboratory Model Studies on the Drying Efficiency of Transformer Cellulose Insulation Using Synthetic Ester

et al. 2020

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“…The results of the research presented in [56] show that the amount of water removed from the solid insulation decreases significantly as the thickness of the cellulose material grows. This In accordance with the information from [53], the application of synthetic ester Midel 7131 for retro-filling a transformer depends on the voltage and power rating of the unit.…”

Section: Dryingmentioning

confidence: 98%

“…The results of the research presented in [56] show that the amount of water removed from the solid insulation decreases significantly as the thickness of the cellulose material grows. This dependence was observed for cellulose materials up to about 3 mm thick.…”

Section: Dryingmentioning

confidence: 98%

“…It involves the replacement of mineral oil in a transformer on ester liquid and thus reducing the potential environmental impact [49][50][51][52][53]. There are also some studies where the benefits of synthetic esters connected with its water solubility are used in the process of drying transformers [54][55][56][57][58]. The chemical structure of synthetic esters was found to be a reason for some disadvantages in the field of their behavior under lightning impulses (LIs): the dielectric performances of synthetic esters under these stresses are the worse ones [26,[59][60][61][62][63].…”

Section: Chemical Properties Of Synthetic Estersmentioning

confidence: 99%

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A Review on Synthetic Ester Liquids for Transformer Applications

et al. 2020

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Synthetic esters have become more and more popular in last few decades, explaining the increasing number of units filled with this liquid year by year. They have been investigated under different aspects, both from the fundamental point of view and breakdown mechanisms, well as from the application point of view. However, their use in high voltage equipment is always a challenge and deeper knowledge of the various aspects that can be encountered in their exploitation is needed. The intent of this review paper is to present the recent research progress on synthetic ester liquid in relation to the selected issues, most important for ester development in the authors’ opinion. The described issues are the breakdown performance of synthetic esters, lightning impulse strength and pre-breakdown phenomena of synthetic esters, synthetic esters-based nanofluids, combined paper-synthetic ester based insulating systems, application of synthetic ester for retro-filling and drying of mineral oil-immersed transformers, DGA(dissolved gas analysis)-based diagnosis of synthetic esters filled transformers as well as static electrification of synthetic esters. The different sections are based both on the data available in the literature, but above all on the authors’ own experience from their research work on synthetic ester liquids for electrical application purposes.

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“…The above aspects have been the subject of research for those interested in alternative liquid dielectrics. Several researchers reported the potential of ester dielectric fluids as a possible alternative to mineral oil [2][3][4]. However, there is still a great scope for research on understanding the compatibility of these new insulating fluids with transformer operating conditions.…”

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confidence: 99%

Influence of Aging on Oil Degradation and Gassing Tendency for Mineral oil and Synthetic Ester under Low Energy Discharge Electrical Faults

2020

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The intent of this work is to understand the influence of low energy discharge electric faults in mineral oil and synthetic esters on liquid degradation and gassing tendency at different aging conditions (based on acidity values). A low energy discharge electric fault has been created by continuous discharge of 9 kV for five hours on the liquid surface using a suitable laboratory setup. Liquid degradation is reported by adopting UV spectroscopy, turbidity, and particle counter measurements. The gassing tendency is understood by dissolved gas analysis using Duval’s triangle and Duval’s pentagon methods for mineral oil and non-mineral oils accordingly. It is observed that the influence of low energy discharges on liquid degradation is higher in mineral oils than synthetic esters. The fault gasses in mineral oil are involved with electrical and thermal faults accompanied by stray gassing whereas only partial discharge activity is noticed for synthetic esters. Importantly, the existence of low energy discharge faults like corona discharges will involve a generation of excess high molecular weight products as compared to low molecular weight products that are soluble in liquid volume.

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Application of Synthetic Ester for Drying Distribution Transformer Insulation—The Influence of Cellulose Thickness on Drying Efficiency

Cited by 13 publications

References 37 publications

Laboratory Model Studies on the Drying Efficiency of Transformer Cellulose Insulation Using Synthetic Ester

Laboratory Model Studies on the Drying Efficiency of Transformer Cellulose Insulation Using Synthetic Ester

A Review on Synthetic Ester Liquids for Transformer Applications

Influence of Aging on Oil Degradation and Gassing Tendency for Mineral oil and Synthetic Ester under Low Energy Discharge Electrical Faults

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