Pub Date : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437444
S. Masuda, K. Tohyama, T. Iizuka, K. Tatsumi, S. Yoshida, T. Umemoto, T. Mabuchi, H. Muto
This paper investigates the electroluminescence (EL) and the dissipation current properties of the Epoxy/Ti02 nanocomposites under AC ramp electric field application. The volume fractions of the samples are 1, 5, 10 and 20 vol%. As a result, the inception and the extinction electric field of the EL, 2nd and 3rd harmonics of the dissipation current increased with decreasing the volume fractions. Furthermore, the nanocomposite sample with the volume fraction of 1 vol% showed the superior results compared to the neat epoxy sample. It is considered that the small amount of the nanofiller additives and the resulting homogeneous nanofiller dispersion within the epoxy is important to improve the performances.
{"title":"Electroluminescence of Epoxy Resin Nanocomposite under AC High Field II","authors":"S. Masuda, K. Tohyama, T. Iizuka, K. Tatsumi, S. Yoshida, T. Umemoto, T. Mabuchi, H. Muto","doi":"10.1109/CEIDP49254.2020.9437444","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437444","url":null,"abstract":"This paper investigates the electroluminescence (EL) and the dissipation current properties of the Epoxy/Ti02 nanocomposites under AC ramp electric field application. The volume fractions of the samples are 1, 5, 10 and 20 vol%. As a result, the inception and the extinction electric field of the EL, 2nd and 3rd harmonics of the dissipation current increased with decreasing the volume fractions. Furthermore, the nanocomposite sample with the volume fraction of 1 vol% showed the superior results compared to the neat epoxy sample. It is considered that the small amount of the nanofiller additives and the resulting homogeneous nanofiller dispersion within the epoxy is important to improve the performances.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115152775","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437539
Jiale Wu, Xupeng Song, Yan-Yan Gong, X. Bian
Prefabricated rubber stress cone is the key part of the high-voltage cable terminal. Material with nonlinear conductivity can smartly smooth the non-uniform electrical field of the stress cone. Reasonable selection of the nonlinear coefficient is critical for determining the applicability of the nonlinear materials. The effects of nonlinear composite with different nonlinear coefficient on field grading effect, power loss and temperature distribution are simulated by establishing finite element numerical model of the 110kV AC cable terminal. The results indicate that with the increase of nonlinear coefficient, the electric field strength of the stress cone surface gradually decreases while that of the three-phase junction gradually increases. Although the power loss of the stress cone insulation increases, the resulting temperature rise is minimal. Considering field grading effect, the power loss and temperature rise, for 110kV AC cable terminal, nonlinear material with threshold electric field of 0.8MV/m and nonlinear coefficient of 7.5-11.5 is more suitable for operation environment.
{"title":"Simulation Research on the Application of Nonlinear Conductivity Material in 110kV Cable Terminal with Electro-thermal Coupling Model","authors":"Jiale Wu, Xupeng Song, Yan-Yan Gong, X. Bian","doi":"10.1109/CEIDP49254.2020.9437539","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437539","url":null,"abstract":"Prefabricated rubber stress cone is the key part of the high-voltage cable terminal. Material with nonlinear conductivity can smartly smooth the non-uniform electrical field of the stress cone. Reasonable selection of the nonlinear coefficient is critical for determining the applicability of the nonlinear materials. The effects of nonlinear composite with different nonlinear coefficient on field grading effect, power loss and temperature distribution are simulated by establishing finite element numerical model of the 110kV AC cable terminal. The results indicate that with the increase of nonlinear coefficient, the electric field strength of the stress cone surface gradually decreases while that of the three-phase junction gradually increases. Although the power loss of the stress cone insulation increases, the resulting temperature rise is minimal. Considering field grading effect, the power loss and temperature rise, for 110kV AC cable terminal, nonlinear material with threshold electric field of 0.8MV/m and nonlinear coefficient of 7.5-11.5 is more suitable for operation environment.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121239704","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437476
G. Behrmann, D. Gross, S. Neuhold
There is an obvious desire to assign units of charge (pC) to on-site/on-line partial discharge (PD) measurements made using radio-frequency (RF) techniques by employing some means of calibration in a way similar to that defined in IEC 60270. While moving just a few MHz past the IEC 60270 mandated maximum cut-off frequency (1 MHz) may still allow the principle of quasi-integration to hold, and thus allow a valid charge-based calibration, this is strongly dependent on the test object and test circuit. However, at higher (RF/VHF/UHF) frequency regions in which PD diagnostics are often being made today on GIS and HV transformers, physical effects profoundly affect the RF signal generated at the PD source and its path to the receiving sensor, thus directly impacting the received RF signal strength. We explain the problems inherent in attempting charge calibration at these higher frequencies by looking at the fundamental difference in how the measurement methods acquire the PD signal, and we point out the relative unimportance of charge level for certain critical defects.
{"title":"Limitations of Attempting Calibration of Partial Discharge Measurements in VHF and UHF Ranges","authors":"G. Behrmann, D. Gross, S. Neuhold","doi":"10.1109/CEIDP49254.2020.9437476","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437476","url":null,"abstract":"There is an obvious desire to assign units of charge (pC) to on-site/on-line partial discharge (PD) measurements made using radio-frequency (RF) techniques by employing some means of calibration in a way similar to that defined in IEC 60270. While moving just a few MHz past the IEC 60270 mandated maximum cut-off frequency (1 MHz) may still allow the principle of quasi-integration to hold, and thus allow a valid charge-based calibration, this is strongly dependent on the test object and test circuit. However, at higher (RF/VHF/UHF) frequency regions in which PD diagnostics are often being made today on GIS and HV transformers, physical effects profoundly affect the RF signal generated at the PD source and its path to the receiving sensor, thus directly impacting the received RF signal strength. We explain the problems inherent in attempting charge calibration at these higher frequencies by looking at the fundamental difference in how the measurement methods acquire the PD signal, and we point out the relative unimportance of charge level for certain critical defects.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127481891","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437383
He Li, Ding Ai, Yao Zhou, Lulu Ren, Qing Wang
Dielectric polymer film capacitor with high energy density and efficiency is one of the enabling technologies for the development of flexible electronics and power systems. Herein, we introduce wide-bandgap inorganic fillers into the polymer matrices to yield polymer nanocomposites. It is found that the leakage current is largely decreased, and the charge-discharge efficiency is significantly improved of the nanocomposites, especially at high fields and elevated temperatures, compared to polymer matrices. The increase in activation energy indicates that the presence of wide-bandgap nanofillers in the polymer matrix gives rise to a higher barrier to be overcome for occurring conduction processes. In addition, a strong dependence of high-field conduction behavior on the filler morphology is revealed. Compared to zero- and one-dimensional fillers, two-dimensional nanoplate enables the shortest hopping distance, and is the most efficient in inhibiting conduction loss of the polymer composites.
{"title":"Polymer Nanocomposite Capacitors with Largely Reduced Conduction Loss Utilizing Wide-Bandgap Inorganic Nanofillers","authors":"He Li, Ding Ai, Yao Zhou, Lulu Ren, Qing Wang","doi":"10.1109/CEIDP49254.2020.9437383","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437383","url":null,"abstract":"Dielectric polymer film capacitor with high energy density and efficiency is one of the enabling technologies for the development of flexible electronics and power systems. Herein, we introduce wide-bandgap inorganic fillers into the polymer matrices to yield polymer nanocomposites. It is found that the leakage current is largely decreased, and the charge-discharge efficiency is significantly improved of the nanocomposites, especially at high fields and elevated temperatures, compared to polymer matrices. The increase in activation energy indicates that the presence of wide-bandgap nanofillers in the polymer matrix gives rise to a higher barrier to be overcome for occurring conduction processes. In addition, a strong dependence of high-field conduction behavior on the filler morphology is revealed. Compared to zero- and one-dimensional fillers, two-dimensional nanoplate enables the shortest hopping distance, and is the most efficient in inhibiting conduction loss of the polymer composites.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123325982","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437502
Mychal P. Spencer, Andy Zwoster, Tucker T. Bisel, M. Murphy, L. Fifield
Electrical cables are integral to power, control, and instrumentation systems within nuclear power plants (NPPs). Exposure of cable systems within nuclear containment to elevated temperatures and gamma radiation during decades-long operation of NPPs can lead to degradation of the cables' polymeric insulation. Prediction of nuclear cable insulation degradation is complicated because thermal and radiation stress are not additive. In this work, we explore the relative effects of simultaneous and sequential thermal and gamma irradiation on the aging of ethylene-propylene-diene (EPDM) elastomer insulation to better understand realistic scenarios of cable insulation degradation. Cable insulation samples of EPDM were subjected to up to 320 kGy of gamma radiation at a dose rate of 300 Gy/hr in two heating scenarios: (1) simultaneously aged samples were heated at 150°C during irradiation and (2) sequentially aged samples were heated at 150°C for designated durations followed by corresponding periods of irradiation at ambient temperature. The mass, tensile elongation at break, and the carbonyl index were assessed to quantify the aging of the polymers. The simultaneous aging scenario was found to be the more severe of the two for EPDM insulation degradation.
{"title":"Sequential versus Simultaneous Aging of EPDM Nuclear Cable Insulation Subjected to Elevated Temperature and Gamma Radiation","authors":"Mychal P. Spencer, Andy Zwoster, Tucker T. Bisel, M. Murphy, L. Fifield","doi":"10.1109/CEIDP49254.2020.9437502","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437502","url":null,"abstract":"Electrical cables are integral to power, control, and instrumentation systems within nuclear power plants (NPPs). Exposure of cable systems within nuclear containment to elevated temperatures and gamma radiation during decades-long operation of NPPs can lead to degradation of the cables' polymeric insulation. Prediction of nuclear cable insulation degradation is complicated because thermal and radiation stress are not additive. In this work, we explore the relative effects of simultaneous and sequential thermal and gamma irradiation on the aging of ethylene-propylene-diene (EPDM) elastomer insulation to better understand realistic scenarios of cable insulation degradation. Cable insulation samples of EPDM were subjected to up to 320 kGy of gamma radiation at a dose rate of 300 Gy/hr in two heating scenarios: (1) simultaneously aged samples were heated at 150°C during irradiation and (2) sequentially aged samples were heated at 150°C for designated durations followed by corresponding periods of irradiation at ambient temperature. The mass, tensile elongation at break, and the carbonyl index were assessed to quantify the aging of the polymers. The simultaneous aging scenario was found to be the more severe of the two for EPDM insulation degradation.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122560307","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437455
Jindong Huo, Yang Cao
Plasma-solid interaction represents one of the major concerns in many industrial applications, such as power-interruption and plasma-metal processing. Characterized by high-current density and voltage drop, the arc roots dissipate intensive heat that vaporizes the solid counterparts. The generated vapor participates in the ionization and thereby alters the plasma properties, like the electrical conductivity and radiation absorption coefficient. Currently, most of research use the NEC method to estimate the radiative heat transfer. In this study, we consider a banded radiative heat transfer via the Discrete Ordinate method to accurately compute the plasma temperature. It is found that the radiation has great influence on the thermal state of plasma. Apart from the absorption coefficient, the metal vapor also increase the permeability of plasma bulk that will enhance the local magnetic field. For a systematic study, we integrate metal vaporization, species transport and radiative heat transfer into the plasma modelling based on a magnetohydrodynamics method. The simulation results reveal that metal vapor not only helps to alleviate the overall temperature field but also expedite the arc interruption. An accurate computation of metal vapor enhanced radiative heat transfer will enhance the understanding of arc behaviors and improves the design of practically oriented low-voltage circuit breakers.
{"title":"Computational Study of the Arc Splitting in Power Interruption: The Effect of the Metallic Vapor on Arc Dynamics","authors":"Jindong Huo, Yang Cao","doi":"10.1109/CEIDP49254.2020.9437455","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437455","url":null,"abstract":"Plasma-solid interaction represents one of the major concerns in many industrial applications, such as power-interruption and plasma-metal processing. Characterized by high-current density and voltage drop, the arc roots dissipate intensive heat that vaporizes the solid counterparts. The generated vapor participates in the ionization and thereby alters the plasma properties, like the electrical conductivity and radiation absorption coefficient. Currently, most of research use the NEC method to estimate the radiative heat transfer. In this study, we consider a banded radiative heat transfer via the Discrete Ordinate method to accurately compute the plasma temperature. It is found that the radiation has great influence on the thermal state of plasma. Apart from the absorption coefficient, the metal vapor also increase the permeability of plasma bulk that will enhance the local magnetic field. For a systematic study, we integrate metal vaporization, species transport and radiative heat transfer into the plasma modelling based on a magnetohydrodynamics method. The simulation results reveal that metal vapor not only helps to alleviate the overall temperature field but also expedite the arc interruption. An accurate computation of metal vapor enhanced radiative heat transfer will enhance the understanding of arc behaviors and improves the design of practically oriented low-voltage circuit breakers.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123024012","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437506
Mohamadreza Arab Baferani, Chuanyang Li, Tohid Shahsavarian, Ivan Jovanović, Yang Cao
In HVDC cable system, DC connectors e.g. joints and terminations are critical and vulnerable components. This is because of the non-uniform electric field distribution in DC connectors which can enhance the electric field at triple points and lead to degradation and failure in the long time. As a result, for a reliable HVDC cable system, accurate design of the DC connectors plays a vital role. To improve the uniformity of field distribution under all operating conditions especially at the interface of connector and cable insulation, nonlinear field grading material (NLFGM) stems as a viable solution. This study focuses on the development and test of SiR/SiC as NFLGM material for electric field grading in DC cable connectors. To investigate the performance of developed material, an electro-thermal model for 80kV DC cable joint under different thermal gradient conditions was used. The electric field distribution in the joint and across the interface of cable insulation and SiR as the joint insulation with and without NLFGM were simulated. The results show significant change in distribution of electric potential and decrease in amplitude of electric field in presence of NLFGM.
{"title":"Development of Nonlinear Field Grading Material for Controlling Electric Field in DC Connectors","authors":"Mohamadreza Arab Baferani, Chuanyang Li, Tohid Shahsavarian, Ivan Jovanović, Yang Cao","doi":"10.1109/CEIDP49254.2020.9437506","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437506","url":null,"abstract":"In HVDC cable system, DC connectors e.g. joints and terminations are critical and vulnerable components. This is because of the non-uniform electric field distribution in DC connectors which can enhance the electric field at triple points and lead to degradation and failure in the long time. As a result, for a reliable HVDC cable system, accurate design of the DC connectors plays a vital role. To improve the uniformity of field distribution under all operating conditions especially at the interface of connector and cable insulation, nonlinear field grading material (NLFGM) stems as a viable solution. This study focuses on the development and test of SiR/SiC as NFLGM material for electric field grading in DC cable connectors. To investigate the performance of developed material, an electro-thermal model for 80kV DC cable joint under different thermal gradient conditions was used. The electric field distribution in the joint and across the interface of cable insulation and SiR as the joint insulation with and without NLFGM were simulated. The results show significant change in distribution of electric potential and decrease in amplitude of electric field in presence of NLFGM.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114265590","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437482
H. Hamedi, R. Walker, J. Long, R. Rajagopalan, E. Furman, M. Lanagan, W. Woodward
In this study, the byproduct-driven conduction current in LDPE was investigated. We built an experimental fixture to measure bulk conductivity in LDPE soaked with byproducts. Ohmic conduction was observed below 10 kV/mm. At above 10 kV/mm, space charge limited current (SCLC) predicts observed conduction in LDPE soaked with byproducts. It is found that the addition of byproducts introduces charge traps with discrete energy levels which dominate conduction. Degassed samples, on the other hand, show slopes of greater than 2.5 in a current-voltage log-log plot which was attributed to the charge traps with continuous energy levels. By analyzing the thickness dependence of the current, we observed a transition from electrode- to bulk-limited current at above 20 kV/mm for acetophenone- and α-cumyl alcohol-soaked samples. The α-methylstyrene-soaked samples only show electrode-limited current.
{"title":"Impact of the Impurities on the Conductivity of Low-Density Polyethylene","authors":"H. Hamedi, R. Walker, J. Long, R. Rajagopalan, E. Furman, M. Lanagan, W. Woodward","doi":"10.1109/CEIDP49254.2020.9437482","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437482","url":null,"abstract":"In this study, the byproduct-driven conduction current in LDPE was investigated. We built an experimental fixture to measure bulk conductivity in LDPE soaked with byproducts. Ohmic conduction was observed below 10 kV/mm. At above 10 kV/mm, space charge limited current (SCLC) predicts observed conduction in LDPE soaked with byproducts. It is found that the addition of byproducts introduces charge traps with discrete energy levels which dominate conduction. Degassed samples, on the other hand, show slopes of greater than 2.5 in a current-voltage log-log plot which was attributed to the charge traps with continuous energy levels. By analyzing the thickness dependence of the current, we observed a transition from electrode- to bulk-limited current at above 20 kV/mm for acetophenone- and α-cumyl alcohol-soaked samples. The α-methylstyrene-soaked samples only show electrode-limited current.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121924742","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437520
Chen Wang, Yaoyu Xu, Chao Zhu, Yuan Li, Lei Zhang, Date Li, Guanjun Zhang
Power transformers are key components in the power grid, so it is of great importance to protect them from an unplanned outage. With the increase of social electricity consumption, the overload accidents of transformer have become increasingly frequent. In order to avoid the overload accidents, we investigate the loading capacity of transformer based on temperature rise characteristics. Firstly, considering the influence of sunshine radiation, we establish the improved thermal model. Because the DC resistance of winding and oil viscosity change with oil temperature, the algorithms of load loss and thermal resistance are modified to improve the calculation accuracy of hot-spot temperature (HST). Compared with conventional IEC standard method, the relative error of the improved model of hotspot temperature is reduced by about 2.5%. Further, the constraints of loading capacity for transformer are studied. Taken temperature rise characteristics with load current and the loading constraint factors of transformer into account, the evaluation model for loading capacity of transformer is proposed. The results show that the main constraint factor is the relative life loss of transformer under the normal periodic load; the main constraint factor is the capacity of auxiliary equipment of transformer under the long-term emergency load. The capacity of short-term emergency load is not only limited by the top-oil temperature and hot-spot temperature, but also affected by the initial load rate of transformer and the ambient temperature.
{"title":"Load Capacity Evaluation of Power Transformer via Temperature Rise Characteristics","authors":"Chen Wang, Yaoyu Xu, Chao Zhu, Yuan Li, Lei Zhang, Date Li, Guanjun Zhang","doi":"10.1109/CEIDP49254.2020.9437520","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437520","url":null,"abstract":"Power transformers are key components in the power grid, so it is of great importance to protect them from an unplanned outage. With the increase of social electricity consumption, the overload accidents of transformer have become increasingly frequent. In order to avoid the overload accidents, we investigate the loading capacity of transformer based on temperature rise characteristics. Firstly, considering the influence of sunshine radiation, we establish the improved thermal model. Because the DC resistance of winding and oil viscosity change with oil temperature, the algorithms of load loss and thermal resistance are modified to improve the calculation accuracy of hot-spot temperature (HST). Compared with conventional IEC standard method, the relative error of the improved model of hotspot temperature is reduced by about 2.5%. Further, the constraints of loading capacity for transformer are studied. Taken temperature rise characteristics with load current and the loading constraint factors of transformer into account, the evaluation model for loading capacity of transformer is proposed. The results show that the main constraint factor is the relative life loss of transformer under the normal periodic load; the main constraint factor is the capacity of auxiliary equipment of transformer under the long-term emergency load. The capacity of short-term emergency load is not only limited by the top-oil temperature and hot-spot temperature, but also affected by the initial load rate of transformer and the ambient temperature.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128212134","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 : 2020-10-18DOI: 10.1109/CEIDP49254.2020.9437483
Diana El Khoury, F. Gentils, O. Lesaint, N. Bonifaci
Partial discharges (PDs) are believed to be one of the key factors accelerating high voltage (HV) equipment ageing. The chemical by-products of PDs actively contribute to the modification of insulations surface quality, especially in air medium due to the diversity of its constituents. Although nonthermal plasmas in air have been widely studied, their adaptation to HV systems is still highly complex and prone to controversies. In this work, a typical simulation of a fault leading to PD in air, through a Dielectric Barrier Discharge (DBD) point-to-plane configuration, is performed in order to measure ozone (O3), nitrogen oxide (NO) and dioxide (NO2) by-products gases. The evolution of these species regarding PD duration, PD power and humidity is analyzed. Ozone production rate and dynamics are found to predominate over NO2 and NO ones. The effect of humidity on gases evolution is found to be indirect, as it mainly affects PD power.
{"title":"Analysis of Chemical By-products from Partial Discharges in Air","authors":"Diana El Khoury, F. Gentils, O. Lesaint, N. Bonifaci","doi":"10.1109/CEIDP49254.2020.9437483","DOIUrl":"https://doi.org/10.1109/CEIDP49254.2020.9437483","url":null,"abstract":"Partial discharges (PDs) are believed to be one of the key factors accelerating high voltage (HV) equipment ageing. The chemical by-products of PDs actively contribute to the modification of insulations surface quality, especially in air medium due to the diversity of its constituents. Although nonthermal plasmas in air have been widely studied, their adaptation to HV systems is still highly complex and prone to controversies. In this work, a typical simulation of a fault leading to PD in air, through a Dielectric Barrier Discharge (DBD) point-to-plane configuration, is performed in order to measure ozone (O3), nitrogen oxide (NO) and dioxide (NO2) by-products gases. The evolution of these species regarding PD duration, PD power and humidity is analyzed. Ozone production rate and dynamics are found to predominate over NO2 and NO ones. The effect of humidity on gases evolution is found to be indirect, as it mainly affects PD power.","PeriodicalId":170813,"journal":{"name":"2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128660236","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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