Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158689
T. Hejtmánek, P. Drexler, M. Judd, B. Stewart
This paper reports on an investigation into the application of denoising techniques to improve the arrival time detection of UHF partial discharge (PD) signals, with the aim of refining the spatial localization of PD in power transformers, gas insulated switchgear, and other systems where partial discharges can occur. Noise reduction methods can be applied to signals from various measurement systems including UHF methods or acoustic emission detection. Most existing measurement systems do not normally apply any sophisticated signal processing to suppress noise in the spatial localization of discharges. This can potentially cause inaccuracies in the location of insulation defects position and may inadvertently misdirect modification or repairs of equipment, maintenance inspection of exposed parts or subsequent servicing operation.
{"title":"Comparison of Two Denoising Techniques to Improve UHF Partial Discharge Localization","authors":"T. Hejtmánek, P. Drexler, M. Judd, B. Stewart","doi":"10.1109/eic47619.2020.9158689","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158689","url":null,"abstract":"This paper reports on an investigation into the application of denoising techniques to improve the arrival time detection of UHF partial discharge (PD) signals, with the aim of refining the spatial localization of PD in power transformers, gas insulated switchgear, and other systems where partial discharges can occur. Noise reduction methods can be applied to signals from various measurement systems including UHF methods or acoustic emission detection. Most existing measurement systems do not normally apply any sophisticated signal processing to suppress noise in the spatial localization of discharges. This can potentially cause inaccuracies in the location of insulation defects position and may inadvertently misdirect modification or repairs of equipment, maintenance inspection of exposed parts or subsequent servicing operation.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132829108","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158757
Masamichi Kato, S. Matsumoto
The thermal decomposition mechanism of ester insulating oil was investigated using quantum chemistry computing. The bond dissociation energy of each ester's molecular bond was calculated, activate energy for generation radicals estimated. Gibbs free energy difference before and after bond dissociation was calculated at 300, 400, 500, 600, and 700°C. The reaction rate at each temperature was evaluated, and the ratio of each radical was estimated. Furthermore, the reaction pathway in which radicals generate gases (H2, CH4, C2H6, C2H4, C2H2) used in DGA was searched by transition state (TS) search and intrinsic reaction coordinate (IRC) analyzing. Finally, the Gibbs free energy for these reaction pathways was calculated and the gas generation rate at each temperature was estimated. Calculated gas generation characteristic trends are consistent with the data of local heating experiments previously reported.
{"title":"Quantum Chemistry Computing to analyze the Gas Generation Mechanism in Ester Insulating Oils","authors":"Masamichi Kato, S. Matsumoto","doi":"10.1109/eic47619.2020.9158757","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158757","url":null,"abstract":"The thermal decomposition mechanism of ester insulating oil was investigated using quantum chemistry computing. The bond dissociation energy of each ester's molecular bond was calculated, activate energy for generation radicals estimated. Gibbs free energy difference before and after bond dissociation was calculated at 300, 400, 500, 600, and 700°C. The reaction rate at each temperature was evaluated, and the ratio of each radical was estimated. Furthermore, the reaction pathway in which radicals generate gases (H2, CH4, C2H6, C2H4, C2H2) used in DGA was searched by transition state (TS) search and intrinsic reaction coordinate (IRC) analyzing. Finally, the Gibbs free energy for these reaction pathways was calculated and the gas generation rate at each temperature was estimated. Calculated gas generation characteristic trends are consistent with the data of local heating experiments previously reported.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129405993","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158574
I. Hosier, A. Vaughan, O. Cwikowski
In view of its widespread use in cable terminations, new results pertaining to electrical aging (i.e. exposure to repeated electrical discharge events) of silicone oil are reported. A new piece of equipment allowed the discharge characteristics to be controlled and the resulting blackening was correlated to the change in dielectric properties. End of life conditions were determined and the feasibility of a simple optical probe was explored. This could give the operator warning of when the oil is excessively aged, allowing remedial action to be taken.
{"title":"Electrical aging of silicone oil","authors":"I. Hosier, A. Vaughan, O. Cwikowski","doi":"10.1109/eic47619.2020.9158574","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158574","url":null,"abstract":"In view of its widespread use in cable terminations, new results pertaining to electrical aging (i.e. exposure to repeated electrical discharge events) of silicone oil are reported. A new piece of equipment allowed the discharge characteristics to be controlled and the resulting blackening was correlated to the change in dielectric properties. End of life conditions were determined and the feasibility of a simple optical probe was explored. This could give the operator warning of when the oil is excessively aged, allowing remedial action to be taken.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"19 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133424937","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 : 2020-06-01DOI: 10.1109/EIC47619.2020.9158726
H. Naderiallaf, A. Cavallini, Florian Esterl, R. Plath, P. Seri, G. Montanari
Starting from measurements performed on insulation models, estimation of partial discharge inception voltage, PDIV, and inference of the different behavior of PD for a MV cable models are presented and discussed. The estimations are validated through laboratory testing on a cable with an artificial defect. It is shown that PDIV under DC can become considerably higher or lower than that under AC, depending on temperature and material properties, which affect PD repetition rate as well. However, resorting to the model presented in this paper, measuring PD under AC will help to identify and validate the results of the PD DC measurements.
{"title":"Measuring partial discharges in MV cables under DC voltage: procedures and results in steady state conditions","authors":"H. Naderiallaf, A. Cavallini, Florian Esterl, R. Plath, P. Seri, G. Montanari","doi":"10.1109/EIC47619.2020.9158726","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158726","url":null,"abstract":"Starting from measurements performed on insulation models, estimation of partial discharge inception voltage, PDIV, and inference of the different behavior of PD for a MV cable models are presented and discussed. The estimations are validated through laboratory testing on a cable with an artificial defect. It is shown that PDIV under DC can become considerably higher or lower than that under AC, depending on temperature and material properties, which affect PD repetition rate as well. However, resorting to the model presented in this paper, measuring PD under AC will help to identify and validate the results of the PD DC measurements.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116163175","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158713
Luciano Enciso, R. Álvarez, José L. Martínez, P. Arce, M. Galliani, Pablo Rodriguez, Emilo Calo
High voltage bushing failures are one of the main causes that affect reliability and availability of high voltage transformers and reactors. Not only reliability and availability are affected, but also failures in these components could produce fires, damages in nearby equipment and injuries to people working in the proximity. It was shown that performing periodic diagnosis or implementing continuous monitoring help to avoid terminal failures. In order to expand knowledge regarding how high voltage bushings age and how the signs of ageing could be detected, the results of the analysis of six high voltage bushings removed preventively from service are presented in this work. These bushings had been operating for between twenty and thirty-three years before being removed. Three of them were pulled out preventively because diagnoses performed over them showed risk of failure. The analysis includes test of dissipation factor (tan δ) and capacitance, tip-up, frequency domain spectroscopy performed during their life in service and lab tests conducted when they were out of services: dissipation factor and capacitance, frequency domain spectroscopy, tip-up, dissipation factor at nominal voltage, partial discharges, DGA and oil analysis performed in laboratory. At the end of the lab test each bushing was disassembled, and a detailed visual inspection was carried out. Oil samples were taken to carry out physical and chemical analysis. Tests results, both field historical and in laboratory, life time in service, visual inspection and oil sample analysis results are presented correlated with the aim of evaluating failure mechanisms that were present, and analyzing which diagnosis tests have shown to be the most suitable to detect their condition.
{"title":"Incipient failures analysis of high voltage bushings","authors":"Luciano Enciso, R. Álvarez, José L. Martínez, P. Arce, M. Galliani, Pablo Rodriguez, Emilo Calo","doi":"10.1109/eic47619.2020.9158713","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158713","url":null,"abstract":"High voltage bushing failures are one of the main causes that affect reliability and availability of high voltage transformers and reactors. Not only reliability and availability are affected, but also failures in these components could produce fires, damages in nearby equipment and injuries to people working in the proximity. It was shown that performing periodic diagnosis or implementing continuous monitoring help to avoid terminal failures. In order to expand knowledge regarding how high voltage bushings age and how the signs of ageing could be detected, the results of the analysis of six high voltage bushings removed preventively from service are presented in this work. These bushings had been operating for between twenty and thirty-three years before being removed. Three of them were pulled out preventively because diagnoses performed over them showed risk of failure. The analysis includes test of dissipation factor (tan δ) and capacitance, tip-up, frequency domain spectroscopy performed during their life in service and lab tests conducted when they were out of services: dissipation factor and capacitance, frequency domain spectroscopy, tip-up, dissipation factor at nominal voltage, partial discharges, DGA and oil analysis performed in laboratory. At the end of the lab test each bushing was disassembled, and a detailed visual inspection was carried out. Oil samples were taken to carry out physical and chemical analysis. Tests results, both field historical and in laboratory, life time in service, visual inspection and oil sample analysis results are presented correlated with the aim of evaluating failure mechanisms that were present, and analyzing which diagnosis tests have shown to be the most suitable to detect their condition.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121855820","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158769
Chen Yingyu, Zhang Yubo, Wang Youyuan, Fang Jian
In the fault diagnosis of distribution transformer, in order to fully consider the influence of environmental factors and operation data on distribution transformer, a method of fault diagnosis model of distribution transformer considering environmental factors and operation data is established. First of all, according to the fault data of distribution transformer provided by Guangzhou Power Supply Bureau in recent five years, the environmental factors causing the fault of distribution transformer are calculated. The association rule mining algorithm is used to mine the external environmental factors of distribution transformer fault, and find out the external environmental factors that have a high impact on distribution transformer; secondly, according to the operation data of distribution transformer fault, select the important operation data of distribution transformer fault, and calculate the deviation between the data and the standard value, and take the final result as one of the evaluation indicators; then, in the use of Based on the evaluation of internal test data, the external factors and operation data are fully integrated into the model to establish a complete evaluation model. Finally, the health level of a 10kV distribution transformer in Guangzhou is evaluated in real time in one day. The research of this paper can provide reference for the fault diagnosis and operation maintenance of 10kV distribution transformer
{"title":"State evaluation model of distribution transformer considering environmental factors and operation data","authors":"Chen Yingyu, Zhang Yubo, Wang Youyuan, Fang Jian","doi":"10.1109/eic47619.2020.9158769","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158769","url":null,"abstract":"In the fault diagnosis of distribution transformer, in order to fully consider the influence of environmental factors and operation data on distribution transformer, a method of fault diagnosis model of distribution transformer considering environmental factors and operation data is established. First of all, according to the fault data of distribution transformer provided by Guangzhou Power Supply Bureau in recent five years, the environmental factors causing the fault of distribution transformer are calculated. The association rule mining algorithm is used to mine the external environmental factors of distribution transformer fault, and find out the external environmental factors that have a high impact on distribution transformer; secondly, according to the operation data of distribution transformer fault, select the important operation data of distribution transformer fault, and calculate the deviation between the data and the standard value, and take the final result as one of the evaluation indicators; then, in the use of Based on the evaluation of internal test data, the external factors and operation data are fully integrated into the model to establish a complete evaluation model. Finally, the health level of a 10kV distribution transformer in Guangzhou is evaluated in real time in one day. The research of this paper can provide reference for the fault diagnosis and operation maintenance of 10kV distribution transformer","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122013229","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158654
C. Van de Steen, C. Abadie, G. Bélijar
The present paper reports a comparison between experimental and simulated partial discharge detection. The transition toward greener transportation solution, such as hybrid or all electric aircraft, imply the use of higher voltage to mitigate the mass. Experimental measurement of partial discharge is possible but does not always provide results on the location of the discharge or on the different possibilities to avoid them. The aim of this paper is to examine results provided by a software (AIRLIFT), using as input electrostatic simulation, to a) predict the Partial Discharge Ignition Voltage (PDIV), b) localize the Partial Discharge (PD), c) be able to directly modify the design in order to increase the PDIV and d) compare the simulated results to experimental ones. To do so, twisted pairs samples were studied experimentally and numerically, under different environmental constraints to simulate aeronautical environment, in order to obtain and compare the PDIV. This paper will briefly present the theory and the equipment used, the different results obtained and a comparison between them. Current limitations of the simulations will also be discussed.
{"title":"Partial discharge detection, Experimental-Simulation Comparison and actual limits","authors":"C. Van de Steen, C. Abadie, G. Bélijar","doi":"10.1109/eic47619.2020.9158654","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158654","url":null,"abstract":"The present paper reports a comparison between experimental and simulated partial discharge detection. The transition toward greener transportation solution, such as hybrid or all electric aircraft, imply the use of higher voltage to mitigate the mass. Experimental measurement of partial discharge is possible but does not always provide results on the location of the discharge or on the different possibilities to avoid them. The aim of this paper is to examine results provided by a software (AIRLIFT), using as input electrostatic simulation, to a) predict the Partial Discharge Ignition Voltage (PDIV), b) localize the Partial Discharge (PD), c) be able to directly modify the design in order to increase the PDIV and d) compare the simulated results to experimental ones. To do so, twisted pairs samples were studied experimentally and numerically, under different environmental constraints to simulate aeronautical environment, in order to obtain and compare the PDIV. This paper will briefly present the theory and the equipment used, the different results obtained and a comparison between them. Current limitations of the simulations will also be discussed.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129132599","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 : 2020-06-01DOI: 10.1109/EIC47619.2020.9158765
Xing Fan, Qiaogen Zhang, Yi Zhao, Zhehao Pei, Weijiang Chen, Tao Wen, Yu Zhang, Jiahui Yang
The isolation switch is one of the most commonly used high-voltage electrical equipment in the power grid, and its stability and service life directly affect the operation of the power grid. The fast calculation method of the hot spot temperature for isolation switch is an important contents of online monitoring. However, the numerical calculation method of the thermal field distribution commonly used currently has a slow calculation speed, complicated modeling and change calculation conditions, and is difficult to apply. Therefore, this paper proposes an improved method for calculating the hot spot temperature of an isolating switch based on a thermal circuit model, which can better balance the accuracy and calculation speed. This article analyzes the GW16-550 outdoor high-voltage AC isolating switch. The calculation results show that the hot spot is located at the contact point of the contact. Under the rated conditions, the hot spot temperature is about 20 K higher than the ambient temperature. The hot spot temperature decreases with the increase of wind speed, and changes significantly at low wind speeds. Hot spot temperature is directly proportional to ambient temperature and service life. This research provides support for the research of hotspot temperature for isolation switch, and has certain practical value.
{"title":"Calculation method of hot spot temperature of isolation switch based on improved heat path model","authors":"Xing Fan, Qiaogen Zhang, Yi Zhao, Zhehao Pei, Weijiang Chen, Tao Wen, Yu Zhang, Jiahui Yang","doi":"10.1109/EIC47619.2020.9158765","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158765","url":null,"abstract":"The isolation switch is one of the most commonly used high-voltage electrical equipment in the power grid, and its stability and service life directly affect the operation of the power grid. The fast calculation method of the hot spot temperature for isolation switch is an important contents of online monitoring. However, the numerical calculation method of the thermal field distribution commonly used currently has a slow calculation speed, complicated modeling and change calculation conditions, and is difficult to apply. Therefore, this paper proposes an improved method for calculating the hot spot temperature of an isolating switch based on a thermal circuit model, which can better balance the accuracy and calculation speed. This article analyzes the GW16-550 outdoor high-voltage AC isolating switch. The calculation results show that the hot spot is located at the contact point of the contact. Under the rated conditions, the hot spot temperature is about 20 K higher than the ambient temperature. The hot spot temperature decreases with the increase of wind speed, and changes significantly at low wind speeds. Hot spot temperature is directly proportional to ambient temperature and service life. This research provides support for the research of hotspot temperature for isolation switch, and has certain practical value.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127803194","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158766
Kaige Yang, M. Dong, Yizhuo Hu, Jiacheng Xie, M. Ren
Frequency Domain Spectrum analysis method (FDS), for its lots of advantages, has been widely concerned and applied in state characterization of insulating materials and insulation diagnosis of power equipment. However, in the current research, the characteristic parameters of FDS are not reliable and accurate enough in the field of bushing insulation damp diagnosis. This paper aims to introduce the new concept of dielectric modulus, the inverse of complex permittivity, to the oil-impregnated paper. The dielectric modulus shows great characters in low frequency region, meanwhile the peak of the imaginary part moves to the higher frequency when the water content increases.
{"title":"The Application of Dielectric Modulus in the Oil-impregnated Paper Insulation","authors":"Kaige Yang, M. Dong, Yizhuo Hu, Jiacheng Xie, M. Ren","doi":"10.1109/eic47619.2020.9158766","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158766","url":null,"abstract":"Frequency Domain Spectrum analysis method (FDS), for its lots of advantages, has been widely concerned and applied in state characterization of insulating materials and insulation diagnosis of power equipment. However, in the current research, the characteristic parameters of FDS are not reliable and accurate enough in the field of bushing insulation damp diagnosis. This paper aims to introduce the new concept of dielectric modulus, the inverse of complex permittivity, to the oil-impregnated paper. The dielectric modulus shows great characters in low frequency region, meanwhile the peak of the imaginary part moves to the higher frequency when the water content increases.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"189 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121431827","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158741
F. Haque, Mojtaba Rostaghi-Chalaki, K. Yousefpour, Charlotte Park
The common practice of assuming constant pressure in the dielectric strength estimation of hot gases is compared with that assuming constant number density. The dielectric strengths of dissociated gaseous He- H2-N2 mixture and $mathbf{SF}_{mathbf{6}}$ are estimated at various temperatures. The compositions of the dissociated gas species at temperatures as high as 5,000 K are obtained by minimizing the Gibbs free energy assuming local chemical equilibrium. The calculated mole fractions of the dissociated gas species and electron-scattering cross section data are used for calculating the density-reduced critical electric field that represents the dielectric strength of the gas mixtures. Through this study, it is shown that the dielectric strength of hot gases depends significantly on the two assumptions, and the assumption of constant pressure results in the underestimation of dielectric strength at high temperatures compared to the assumption of constant number density.
{"title":"Distinct Representations of Hot Gas Dielectric Strength and Their Impact","authors":"F. Haque, Mojtaba Rostaghi-Chalaki, K. Yousefpour, Charlotte Park","doi":"10.1109/eic47619.2020.9158741","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158741","url":null,"abstract":"The common practice of assuming constant pressure in the dielectric strength estimation of hot gases is compared with that assuming constant number density. The dielectric strengths of dissociated gaseous He- H2-N2 mixture and $mathbf{SF}_{mathbf{6}}$ are estimated at various temperatures. The compositions of the dissociated gas species at temperatures as high as 5,000 K are obtained by minimizing the Gibbs free energy assuming local chemical equilibrium. The calculated mole fractions of the dissociated gas species and electron-scattering cross section data are used for calculating the density-reduced critical electric field that represents the dielectric strength of the gas mixtures. Through this study, it is shown that the dielectric strength of hot gases depends significantly on the two assumptions, and the assumption of constant pressure results in the underestimation of dielectric strength at high temperatures compared to the assumption of constant number density.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"593 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123143606","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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