Pub Date : 2022-10-23DOI: 10.23919/ARWtr54586.2022.9959917
A. Al-Abadi, A. Gamil, Markus Franke, Tobias Lehrer, Marcus Wagner
During the factory acceptance test, the sound levels are measured. If the measured sound levels exceed pre-specified values, modifications must be made to the transformer’s active part or tank. Tank resonance at twice the main power frequency and its higher harmonics, if it occurs, is one of the main reasons of the amplification of the generated sound levels. Therefore, it is preferable to know in the early design stage about the occurrence of tank resonance and propose reliable solutions. The current study presents a newly developed model for calculating the mode shapes and the corresponding eigenfrequencies of the tank. Finite element simulations and an impact hammer test are conducted on a case study transformer to validate the model results.
{"title":"A Tank Resonance Model for Power Transformers","authors":"A. Al-Abadi, A. Gamil, Markus Franke, Tobias Lehrer, Marcus Wagner","doi":"10.23919/ARWtr54586.2022.9959917","DOIUrl":"https://doi.org/10.23919/ARWtr54586.2022.9959917","url":null,"abstract":"During the factory acceptance test, the sound levels are measured. If the measured sound levels exceed pre-specified values, modifications must be made to the transformer’s active part or tank. Tank resonance at twice the main power frequency and its higher harmonics, if it occurs, is one of the main reasons of the amplification of the generated sound levels. Therefore, it is preferable to know in the early design stage about the occurrence of tank resonance and propose reliable solutions. The current study presents a newly developed model for calculating the mode shapes and the corresponding eigenfrequencies of the tank. Finite element simulations and an impact hammer test are conducted on a case study transformer to validate the model results.","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115821527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/arwtr54586.2022.9959956
{"title":"ARWtr 2022 Back Cover Page","authors":"","doi":"10.23919/arwtr54586.2022.9959956","DOIUrl":"https://doi.org/10.23919/arwtr54586.2022.9959956","url":null,"abstract":"","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115566036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/ARWtr54586.2022.9959895
Z. Jurković, B. Jurišić, Mladen Markovic, T. Zupan
Calculation of turn-to-turn capacitance in power transformer winding is considered in the paper. Simple analytical expressions for the capacitance of plate and cylindrical capacitors are used. These analytical expressions are improved by adding numerically obtained correction factors. These factors are obtained by analyzing the results of electrostatic 2D FEM calculations of partial winding geometry. The power transformer winding capacitance matrix is calculated using the proposed approach. The results are compared to the 2D FEM.
{"title":"Improved Analytical Calculation of Winding Capacitance Using Correction Factors","authors":"Z. Jurković, B. Jurišić, Mladen Markovic, T. Zupan","doi":"10.23919/ARWtr54586.2022.9959895","DOIUrl":"https://doi.org/10.23919/ARWtr54586.2022.9959895","url":null,"abstract":"Calculation of turn-to-turn capacitance in power transformer winding is considered in the paper. Simple analytical expressions for the capacitance of plate and cylindrical capacitors are used. These analytical expressions are improved by adding numerically obtained correction factors. These factors are obtained by analyzing the results of electrostatic 2D FEM calculations of partial winding geometry. The power transformer winding capacitance matrix is calculated using the proposed approach. The results are compared to the 2D FEM.","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124275345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/ARWtr54586.2022.9959902
S. Müller, D. Braisch, M. Luther, A. Gamil, F. Schatzl, M. Milone
This article presents the methods and results of an experimental study performed to investigate the partial discharge behavior of synthetic ester and gas-to-liquid insulation liquids using a transformer design-based creepage discharge test setup similar to a two-layer winding with barrier insulation. The test setup consisted of a paper-insulated U-shaped copper rod, a circular pressboard disk and a grounding electrode which were submerged in the respective liquid. The study was focused on positive lightning impulse voltages. Partial discharges were detected optically using a photomultiplier tube. The study revealed that the existing design curves for creepage paths cannot be applied to the insulation arrangement. Furthermore, the synthetic ester liquid exhibited partial discharges at 30 % higher electric stress than the gas-to-liquid insulation liquid.
{"title":"Comparing Synthetic Ester and Gas-to-Liquid Insulation Liquids Under Lightning Impulse Voltage Using a Creepage Discharge Test Setup","authors":"S. Müller, D. Braisch, M. Luther, A. Gamil, F. Schatzl, M. Milone","doi":"10.23919/ARWtr54586.2022.9959902","DOIUrl":"https://doi.org/10.23919/ARWtr54586.2022.9959902","url":null,"abstract":"This article presents the methods and results of an experimental study performed to investigate the partial discharge behavior of synthetic ester and gas-to-liquid insulation liquids using a transformer design-based creepage discharge test setup similar to a two-layer winding with barrier insulation. The test setup consisted of a paper-insulated U-shaped copper rod, a circular pressboard disk and a grounding electrode which were submerged in the respective liquid. The study was focused on positive lightning impulse voltages. Partial discharges were detected optically using a photomultiplier tube. The study revealed that the existing design curves for creepage paths cannot be applied to the insulation arrangement. Furthermore, the synthetic ester liquid exhibited partial discharges at 30 % higher electric stress than the gas-to-liquid insulation liquid.","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116801940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/arwtr54586.2022.9959894
{"title":"ARWtr 2022 Committees","authors":"","doi":"10.23919/arwtr54586.2022.9959894","DOIUrl":"https://doi.org/10.23919/arwtr54586.2022.9959894","url":null,"abstract":"","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125559034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/ARWtr54586.2022.9959938
A. Al-Abadi, Stefan Buchner, M. Wagner
The laminated steel core of transformers is one of the main sources of the generated sound, as it is excited by different electromagnetic effects during its normal operation. If the core is excited in its eigenfrequencies, the sound generated by a transformer will increase significantly. Therefore, knowledge of the core’s eigenmodes and -frequencies in an early design stage can decrease expenses by avoiding costly modifications that might be required to avoid the sound levels exceeding the specified values after the final factory acceptance test. The current study focuses on developing a core resonance model to determine the eigenmodes and -frequencies of a transformer core. The core’s geometry was simplified to a connected-beam structure and a numerical-based approach was applied. The accuracy of the developed model was validated against finite element method (FEM), using ANSYS on a reference three-leg core model.
{"title":"A Numerical-Based Model to Determine the Resonance of the Steel Cores of Transformers","authors":"A. Al-Abadi, Stefan Buchner, M. Wagner","doi":"10.23919/ARWtr54586.2022.9959938","DOIUrl":"https://doi.org/10.23919/ARWtr54586.2022.9959938","url":null,"abstract":"The laminated steel core of transformers is one of the main sources of the generated sound, as it is excited by different electromagnetic effects during its normal operation. If the core is excited in its eigenfrequencies, the sound generated by a transformer will increase significantly. Therefore, knowledge of the core’s eigenmodes and -frequencies in an early design stage can decrease expenses by avoiding costly modifications that might be required to avoid the sound levels exceeding the specified values after the final factory acceptance test. The current study focuses on developing a core resonance model to determine the eigenmodes and -frequencies of a transformer core. The core’s geometry was simplified to a connected-beam structure and a numerical-based approach was applied. The accuracy of the developed model was validated against finite element method (FEM), using ANSYS on a reference three-leg core model.","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114271898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/arwtr54586.2022.9959897
{"title":"ARWtr 2022 TOC","authors":"","doi":"10.23919/arwtr54586.2022.9959897","DOIUrl":"https://doi.org/10.23919/arwtr54586.2022.9959897","url":null,"abstract":"","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132936171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/arwtr54586.2022.9959930
{"title":"ARWtr 2022 Preface","authors":"","doi":"10.23919/arwtr54586.2022.9959930","DOIUrl":"https://doi.org/10.23919/arwtr54586.2022.9959930","url":null,"abstract":"","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115073366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/ARWtr54586.2022.9959948
D. J. de la Plata, M. Perez, M. de Haro, A. de Pablo
This paper goes on to describe gas generation in windfarm transformers. (WTTs – Wind Turbine Transformers). Local transformers, those directly linked to the turbine of a wind farm, generate abnormally high amounts of dissolved gases. This is virtually independent of the type of transformer (pad mount or distribution) and the type of fluid (mineral oil or synthetic ester) contained in the transformer.The causes of this anomalous gas formation are not fully understood yet, although some possibilities have been proposed, such as a breakage or delamination of the core, harmonics, low voltage fault ride through, over voltage size limitation, variable loading cycle or switching surges and transient overvoltages.Nor can it be ruled out that the cause of these gases could be the interaction of the transformer with the electrical system: windfarm design.These causes are discussed in the paper.
{"title":"Gassing in Windfarm Transformers","authors":"D. J. de la Plata, M. Perez, M. de Haro, A. de Pablo","doi":"10.23919/ARWtr54586.2022.9959948","DOIUrl":"https://doi.org/10.23919/ARWtr54586.2022.9959948","url":null,"abstract":"This paper goes on to describe gas generation in windfarm transformers. (WTTs – Wind Turbine Transformers). Local transformers, those directly linked to the turbine of a wind farm, generate abnormally high amounts of dissolved gases. This is virtually independent of the type of transformer (pad mount or distribution) and the type of fluid (mineral oil or synthetic ester) contained in the transformer.The causes of this anomalous gas formation are not fully understood yet, although some possibilities have been proposed, such as a breakage or delamination of the core, harmonics, low voltage fault ride through, over voltage size limitation, variable loading cycle or switching surges and transient overvoltages.Nor can it be ruled out that the cause of these gases could be the interaction of the transformer with the electrical system: windfarm design.These causes are discussed in the paper.","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134062882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-23DOI: 10.23919/ARWtr54586.2022.9959909
I. Madshaven, L. Lundgaard, H. Enoksen, S. Jaufer, C. Krause, Borut Prašnikar, A. Mjelve
This paper presents a novel system for measuring the clamping pressure of transformer windings. The clamping pressure is essential for the integrity of a transformer during short circuit events. The introduction of new loading patterns, increased dynamic loading, may accelerate cellulose degradation and reduced clamping pressure. Direct measured clamping pressure and temperatures together with physical models will facilitate condition-based maintenance and digital twins. The paper explains how the sensors work and presents data from a heat run test as well as in-service conditions. It is demonstrated how the clamping pressure changes with the transformer loading and temperature.
{"title":"On-line Direct Clamping Pressure Monitoring of Power Transformer Windings","authors":"I. Madshaven, L. Lundgaard, H. Enoksen, S. Jaufer, C. Krause, Borut Prašnikar, A. Mjelve","doi":"10.23919/ARWtr54586.2022.9959909","DOIUrl":"https://doi.org/10.23919/ARWtr54586.2022.9959909","url":null,"abstract":"This paper presents a novel system for measuring the clamping pressure of transformer windings. The clamping pressure is essential for the integrity of a transformer during short circuit events. The introduction of new loading patterns, increased dynamic loading, may accelerate cellulose degradation and reduced clamping pressure. Direct measured clamping pressure and temperatures together with physical models will facilitate condition-based maintenance and digital twins. The paper explains how the sensors work and presents data from a heat run test as well as in-service conditions. It is demonstrated how the clamping pressure changes with the transformer loading and temperature.","PeriodicalId":261952,"journal":{"name":"2022 7th International Advanced Research Workshop on Transformers (ARWtr)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132040198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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