Pub Date : 2019-06-01DOI: 10.1109/EIC43217.2019.9046573
Xu Zhang, Chengxing Lian, C. Emersic, I. Cotton
Overhead lines can generate significant levels of audible noise containing low frequency hum and/or high frequency crackling. The frequency of hum is twice the supply frequency while the crackling noise is in the frequency range of 1 kHz to 20 kHz. While conductor choice and the use of bundles can reduce electric fields and minimize noise, some surface defects including damage, insects, raindrops and pollution will always enhance electric fields and lead to noise generation. This results in the need to use specific conductor types/geometries to avoid the creation of a significant nuisance. This paper presents work that has examined whether the noise level generated by an overhead line can be reduced by coating overhead line conductors with superhydrophobic coating. To test audible noise, an enclosed chamber with a low noise level is utilized. The conductor is either bare or coated with a superhydrophobic coating of which contact angle is 168°. With water manually placed on the conductor, the noise levels at 100 Hz are higher than background noise at different voltages, showing that the noise at 100 Hz is generated by water droplets on the conductor. Furthermore, compared with a bare conductor, testing of the conductor with a superhydrophobic coating shows lower noise levels at 100 Hz under different voltages. The superhydrophobic coating can be used to reduce noise levels at low frequency because water droplets, the reason for the hum, cannot stay on the conductor.
{"title":"Acoustic noise emitted from overhead line conductors with superhydrophobic coating","authors":"Xu Zhang, Chengxing Lian, C. Emersic, I. Cotton","doi":"10.1109/EIC43217.2019.9046573","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046573","url":null,"abstract":"Overhead lines can generate significant levels of audible noise containing low frequency hum and/or high frequency crackling. The frequency of hum is twice the supply frequency while the crackling noise is in the frequency range of 1 kHz to 20 kHz. While conductor choice and the use of bundles can reduce electric fields and minimize noise, some surface defects including damage, insects, raindrops and pollution will always enhance electric fields and lead to noise generation. This results in the need to use specific conductor types/geometries to avoid the creation of a significant nuisance. This paper presents work that has examined whether the noise level generated by an overhead line can be reduced by coating overhead line conductors with superhydrophobic coating. To test audible noise, an enclosed chamber with a low noise level is utilized. The conductor is either bare or coated with a superhydrophobic coating of which contact angle is 168°. With water manually placed on the conductor, the noise levels at 100 Hz are higher than background noise at different voltages, showing that the noise at 100 Hz is generated by water droplets on the conductor. Furthermore, compared with a bare conductor, testing of the conductor with a superhydrophobic coating shows lower noise levels at 100 Hz under different voltages. The superhydrophobic coating can be used to reduce noise levels at low frequency because water droplets, the reason for the hum, cannot stay on the conductor.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124513539","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046576
Ja-Moon Yoon, Jinghun Kwon, J. Ryu, Cheayoon Bae, Jongung Choi, Younggeun Kim
In electric power equipment, the insulator is an important item. Long-term operation of the facility reduces the electrical and mechanical strength of the insulator. This aging of insulator causes fatal defects in the stable operation of the facility. That is, the lifetime of the electric power equipment and the degradation progress of the insulator are closely related. Therefore, the life of an insulator determines the life of equipment. In this paper, a long-term stress experiment was carried out on epoxy resin. Epoxy is mainly used as a spacer material for GIS. The aging stress was tested up to 3000 hours by applying voltage and thermal stress. In order to predict the lifetime of the epoxy resin, V-t characteristics were obtained by using the Weibull distribution. The life parameter $n$ and $A$ was calculated from the V-t characteristics. Also $tandelta$ by the aging progress was measured and plotted on the graph. As a result of the experiment, a life prediction equation of the material by electric stress was presented. Finally, through the relationship between the V-t characteristic and the $tan delta$ characteristic did estimate the aging progress of the insulator.
{"title":"A Study of Relationship Between V-t and $mathrm{Tan}delta$ Characteristic on Epoxy Resin","authors":"Ja-Moon Yoon, Jinghun Kwon, J. Ryu, Cheayoon Bae, Jongung Choi, Younggeun Kim","doi":"10.1109/EIC43217.2019.9046576","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046576","url":null,"abstract":"In electric power equipment, the insulator is an important item. Long-term operation of the facility reduces the electrical and mechanical strength of the insulator. This aging of insulator causes fatal defects in the stable operation of the facility. That is, the lifetime of the electric power equipment and the degradation progress of the insulator are closely related. Therefore, the life of an insulator determines the life of equipment. In this paper, a long-term stress experiment was carried out on epoxy resin. Epoxy is mainly used as a spacer material for GIS. The aging stress was tested up to 3000 hours by applying voltage and thermal stress. In order to predict the lifetime of the epoxy resin, V-t characteristics were obtained by using the Weibull distribution. The life parameter $n$ and $A$ was calculated from the V-t characteristics. Also $tandelta$ by the aging progress was measured and plotted on the graph. As a result of the experiment, a life prediction equation of the material by electric stress was presented. Finally, through the relationship between the V-t characteristic and the $tan delta$ characteristic did estimate the aging progress of the insulator.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122681621","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046631
Jae-Hong Koo, Ho-young Lee, Ryul Hwang, Jong-Min Joo, Jae-Won Park, Bang-wook Lee
The polymer insulator between HVDC converter valve modules is one of the key elements of ultra-high voltage dc transmission. In prior to designing dimension of shed, end fitting, and sealant of polymer insulator, the dc electric field analysis should be conducted. Therefore, the electrical conductivity of the polymer specimens was measured for various temperature since the electrical conductivity depends on the temperature. Based on measured electrical conductivity of specimens, the dc electric field analysis for 4 types of polymer insulators were carried out. From the simulation results, the specimen with the lowest dc electric field was selected. Besides, the dielectric strength of polymer should also be determined in designing the polymer insulator. Therefore, the experiment on determining the dielectric strength of the polymer was conducted. The test jig for breakdown tests was fabricated corresponding to the IEC 60243–1 standard. The dc breakdown tests were corresponded to the IEC 60243–2. In addition to breakdown test, the surface flashover test was also conducted. The test jig was designed using the uniformity of electric field based on the dc electric field analysis and the surface flashover test on the polymer specimens was performed.
{"title":"Design of the Polymer Insulator between HVDC Converter Valve Modules","authors":"Jae-Hong Koo, Ho-young Lee, Ryul Hwang, Jong-Min Joo, Jae-Won Park, Bang-wook Lee","doi":"10.1109/EIC43217.2019.9046631","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046631","url":null,"abstract":"The polymer insulator between HVDC converter valve modules is one of the key elements of ultra-high voltage dc transmission. In prior to designing dimension of shed, end fitting, and sealant of polymer insulator, the dc electric field analysis should be conducted. Therefore, the electrical conductivity of the polymer specimens was measured for various temperature since the electrical conductivity depends on the temperature. Based on measured electrical conductivity of specimens, the dc electric field analysis for 4 types of polymer insulators were carried out. From the simulation results, the specimen with the lowest dc electric field was selected. Besides, the dielectric strength of polymer should also be determined in designing the polymer insulator. Therefore, the experiment on determining the dielectric strength of the polymer was conducted. The test jig for breakdown tests was fabricated corresponding to the IEC 60243–1 standard. The dc breakdown tests were corresponded to the IEC 60243–2. In addition to breakdown test, the surface flashover test was also conducted. The test jig was designed using the uniformity of electric field based on the dc electric field analysis and the surface flashover test on the polymer specimens was performed.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130778078","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046528
Pengfei Yuan, Xuezhong Liu, Tianlong Zhang, Ping Liu
In this paper, the characteristics of a novel type of non-contact electromagnetic induction sensor suitable for inter-turn partial discharge (PD) detection under an induced impulse voltage were studied. Taking the flexible advantage of ferrum-based nanocrystalline alloy thin strip applied in the open magnetic core, the sensor was desigined to be sensitive for the detection of high frequency but low amplitude PD current signal, and had a flexible and thin framework based on consideration of the convenient arrangement at the limted air gapness between the adjacent end-windings of motor. Through the sensor equivalent circuit model established, the curve patterns of the sensor's amplitude gain in the frequency domain were obtained. The transfer characteristics of the sensor were studied by means of theoretical and simulated analysis. The sensor's amplitude performes a bell-shaped characteristic, and its maximum gain can reach 10kV/A at a frequency of about 55 MHz. The finally experimental results, obtained from a typical case of the inverter-fed traction motor windings with the inter-turn void defects, have indicated that the this sensor has a excellent performance in detecting response signal of possible inter-turn PD of motor.
{"title":"Characteristic Research on the Sensor for Inter-turn Partial Discharge Measurement of Inverter-fed Motor Winding","authors":"Pengfei Yuan, Xuezhong Liu, Tianlong Zhang, Ping Liu","doi":"10.1109/EIC43217.2019.9046528","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046528","url":null,"abstract":"In this paper, the characteristics of a novel type of non-contact electromagnetic induction sensor suitable for inter-turn partial discharge (PD) detection under an induced impulse voltage were studied. Taking the flexible advantage of ferrum-based nanocrystalline alloy thin strip applied in the open magnetic core, the sensor was desigined to be sensitive for the detection of high frequency but low amplitude PD current signal, and had a flexible and thin framework based on consideration of the convenient arrangement at the limted air gapness between the adjacent end-windings of motor. Through the sensor equivalent circuit model established, the curve patterns of the sensor's amplitude gain in the frequency domain were obtained. The transfer characteristics of the sensor were studied by means of theoretical and simulated analysis. The sensor's amplitude performes a bell-shaped characteristic, and its maximum gain can reach 10kV/A at a frequency of about 55 MHz. The finally experimental results, obtained from a typical case of the inverter-fed traction motor windings with the inter-turn void defects, have indicated that the this sensor has a excellent performance in detecting response signal of possible inter-turn PD of motor.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128754300","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046601
M. Tousi, M. Ghassemi
We are witnessing an excitement in the research community to develop next-generation wide bandgap (WBG) power electronics. The superior characteristics of WBG materials regarding their operational capability at higher voltages, temperatures (200°C) and switching frequencies in comparison with commercial Silicon devices, has made them auspicious materials for the future power electronics. Increased voltage blocking capability and at the same time, an interest in high-power density designs can enhance the local electric field, in particular, at the edges of the metalized substrate. The increased electric field can become large enough to lead to severe partial discharges (PDs) within the module and thus the failure and reduction of the reliability of the insulation system. This paper shows that applying nonlinear field dependent conductivity (FDC) materials as a coating applied to highly stressed regions combined with a protruding substrate design can well address high field issue within high-voltage high-power-density modules.
{"title":"Nonlinear Field Dependent Conductivity Materials for Electric Field Control within Next-Generation Wide Bandgap Power Electronics Modules","authors":"M. Tousi, M. Ghassemi","doi":"10.1109/EIC43217.2019.9046601","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046601","url":null,"abstract":"We are witnessing an excitement in the research community to develop next-generation wide bandgap (WBG) power electronics. The superior characteristics of WBG materials regarding their operational capability at higher voltages, temperatures (200°C) and switching frequencies in comparison with commercial Silicon devices, has made them auspicious materials for the future power electronics. Increased voltage blocking capability and at the same time, an interest in high-power density designs can enhance the local electric field, in particular, at the edges of the metalized substrate. The increased electric field can become large enough to lead to severe partial discharges (PDs) within the module and thus the failure and reduction of the reliability of the insulation system. This paper shows that applying nonlinear field dependent conductivity (FDC) materials as a coating applied to highly stressed regions combined with a protruding substrate design can well address high field issue within high-voltage high-power-density modules.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127490513","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046561
É. Cloutier-Rioux, H. Provencher, A. Turgeon, C. Hudon
Quality control tests, including partial discharge (PD) measurements and dissections, were performed on a new production lot of epoxy-mica stator bars for a 13.8-kV hydroelectric generator. The location and the characteristic patterns of PD were identified by scanning the straight portion of the bar with an electromagnetic antenna. A sample from those locations was selected for dissection and another sample without PD was selected as a reference. Microscopic analysis of specimens from the sample with localized PD activity showed cavities in the groundwall insulation close to adjacent copper strands. Numerical simulations of the electric field inside different cavities were conducted to determine if PD activity can be initiated in cavities of different shapes. Results of the average and maximum field were compared with the Paschen curve for air. The analysis showed that with the maximum calculated field, all simulated cavities would result in PD activity regardless of the inner temperature.
{"title":"Calculation of the Electric Field Inside Cavities Found Through Stator Bar Dissection","authors":"É. Cloutier-Rioux, H. Provencher, A. Turgeon, C. Hudon","doi":"10.1109/EIC43217.2019.9046561","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046561","url":null,"abstract":"Quality control tests, including partial discharge (PD) measurements and dissections, were performed on a new production lot of epoxy-mica stator bars for a 13.8-kV hydroelectric generator. The location and the characteristic patterns of PD were identified by scanning the straight portion of the bar with an electromagnetic antenna. A sample from those locations was selected for dissection and another sample without PD was selected as a reference. Microscopic analysis of specimens from the sample with localized PD activity showed cavities in the groundwall insulation close to adjacent copper strands. Numerical simulations of the electric field inside different cavities were conducted to determine if PD activity can be initiated in cavities of different shapes. Results of the average and maximum field were compared with the Paschen curve for air. The analysis showed that with the maximum calculated field, all simulated cavities would result in PD activity regardless of the inner temperature.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126693701","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046569
Gao Xu-ze, Z. Tianxin, R. Ming, Song Bo, Huang Wenguang, Dong Ming
Partial discharge monitoring of power cables is an important technical means to ensure the safe operation of cables. However, the traditional cable monitoring method is difficult to apply to the distribution network system with complex feeder structure, wide distribution area and more cost-sensitive. To solve this problem, a cable insulation state sensing technology based on Internet of Things (IOT) technology is proposed in this paper. Firstly, considering scalability and accessibility, the overall framework of wireless sensor network for cable partial discharge monitoring is designed; secondly, the technical requirements of sensor nodes, low power management, data communication and other basic units of Internet of Things sensor network are analyzed; finally, based on the above research, it is realized. Distributed IoT monitoring for high frequency current of partial discharge in power cables. The system has broad application prospects in the on-line monitoring of partial discharge in cables
{"title":"IoT-based On-line Monitoring System for Partial Discharge Diagnosis Of Cable","authors":"Gao Xu-ze, Z. Tianxin, R. Ming, Song Bo, Huang Wenguang, Dong Ming","doi":"10.1109/EIC43217.2019.9046569","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046569","url":null,"abstract":"Partial discharge monitoring of power cables is an important technical means to ensure the safe operation of cables. However, the traditional cable monitoring method is difficult to apply to the distribution network system with complex feeder structure, wide distribution area and more cost-sensitive. To solve this problem, a cable insulation state sensing technology based on Internet of Things (IOT) technology is proposed in this paper. Firstly, considering scalability and accessibility, the overall framework of wireless sensor network for cable partial discharge monitoring is designed; secondly, the technical requirements of sensor nodes, low power management, data communication and other basic units of Internet of Things sensor network are analyzed; finally, based on the above research, it is realized. Distributed IoT monitoring for high frequency current of partial discharge in power cables. The system has broad application prospects in the on-line monitoring of partial discharge in cables","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"90 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117295934","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046523
S. Morrison, J. Kluss, J. Ball, Lucas Cagle, Sam Bryan
High voltage electrical failures are dangerous and costly events in any type of power system. The troubleshooting and diagnostic time required to identify and locate these failures can be significant. Partial discharge is one of the early warning signs for electrical degradation. In insulation systems, partial discharge typically occurs in voids located within the dielectric, at material interfaces, or along energized electrode surfaces. Effective methods for finding this failure precursor enabling circumvention of future catastrophic events are highly valuable as successful detection can improve safety, reduce service interruptions, and result in significant financial savings. The presented method was successful in localizing the excess stress without direct line of sight, a clear advantage over night vision and corona cameras. The investigated methodology provides the ability for any user in varying on-site conditions to quickly and noninvasively diagnose the health of a component or device while maintaining safe clearance from energized parts.
{"title":"Thermal Imaging for Rapid Noninvasive On-site Insulation Diagnostics","authors":"S. Morrison, J. Kluss, J. Ball, Lucas Cagle, Sam Bryan","doi":"10.1109/EIC43217.2019.9046523","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046523","url":null,"abstract":"High voltage electrical failures are dangerous and costly events in any type of power system. The troubleshooting and diagnostic time required to identify and locate these failures can be significant. Partial discharge is one of the early warning signs for electrical degradation. In insulation systems, partial discharge typically occurs in voids located within the dielectric, at material interfaces, or along energized electrode surfaces. Effective methods for finding this failure precursor enabling circumvention of future catastrophic events are highly valuable as successful detection can improve safety, reduce service interruptions, and result in significant financial savings. The presented method was successful in localizing the excess stress without direct line of sight, a clear advantage over night vision and corona cameras. The investigated methodology provides the ability for any user in varying on-site conditions to quickly and noninvasively diagnose the health of a component or device while maintaining safe clearance from energized parts.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115053290","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046525
M. Borghei, M. Ghassemi
Accelerated aging of insulation systems used in different apparatus under fast, repetitive voltage pulses is the most significant barrier to benefit from wide bandgap (WBG) power electronics. Frequency and slew rate which are higher for WGB devices than Si-based ones are two of the most critical factors of a voltage pulse, influencing the level of degradation of the insulation systems that are exposed to such voltage pulses. Finite element analysis (FEA) has been widely used to study partial discharge (PD) behavior under a power frequency (50/60 Hz) sinusoidal waveform within cavities in a solid dielectric. However, the new technologies urge the need to utilize it under square waveforms. In this paper, a FEA model of PD activity is developed. The model is used to investigate the change in the electric field distribution before and after PD occurrence and the impact of different involved parameters when repetitive voltage pulses are applied to the dielectric.
{"title":"Finite Element Modeling of Partial Discharge Activity within a Spherical Cavity in a Solid Dielectric Material under Fast, Repetitive Voltage Pulses","authors":"M. Borghei, M. Ghassemi","doi":"10.1109/EIC43217.2019.9046525","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046525","url":null,"abstract":"Accelerated aging of insulation systems used in different apparatus under fast, repetitive voltage pulses is the most significant barrier to benefit from wide bandgap (WBG) power electronics. Frequency and slew rate which are higher for WGB devices than Si-based ones are two of the most critical factors of a voltage pulse, influencing the level of degradation of the insulation systems that are exposed to such voltage pulses. Finite element analysis (FEA) has been widely used to study partial discharge (PD) behavior under a power frequency (50/60 Hz) sinusoidal waveform within cavities in a solid dielectric. However, the new technologies urge the need to utilize it under square waveforms. In this paper, a FEA model of PD activity is developed. The model is used to investigate the change in the electric field distribution before and after PD occurrence and the impact of different involved parameters when repetitive voltage pulses are applied to the dielectric.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124694581","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046609
L. Raeisian, P. Werle, H. Niazmand
In this article, the natural convection heat transfer of Fe304/oil and graphene/oil nanofluids and mineral oil inside a 200 kVA distribution transformer is numerically studied. The Fe304/oil and graphene/oil nanofluids were simulated as a mixture two-phase flow where mineral oil was modeled as a single-phase flow with the temperature dependent thermophysical properties. Based on the simulation results, the nanoparticles when dispersed in oil enhance the convective heat transfer of oil and decrease its hotspot temperature. So that, the hotspot temperature of the Fe304/oil and graphene/oil were respectively 1 °C and 4.5 °C lower than that of the mineral oil. In addition, the transformer filled with graphene/oil nanofluid experienced considerably lower temperature in the thermally critical region. According to the obtained results, employing the nanofluid improves the cooling performance of the transformer, which leads to a more reliable operation and longer life.
{"title":"Simulation of nanofluid as a two-phase flow in a distribution transformer","authors":"L. Raeisian, P. Werle, H. Niazmand","doi":"10.1109/EIC43217.2019.9046609","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046609","url":null,"abstract":"In this article, the natural convection heat transfer of Fe304/oil and graphene/oil nanofluids and mineral oil inside a 200 kVA distribution transformer is numerically studied. The Fe304/oil and graphene/oil nanofluids were simulated as a mixture two-phase flow where mineral oil was modeled as a single-phase flow with the temperature dependent thermophysical properties. Based on the simulation results, the nanoparticles when dispersed in oil enhance the convective heat transfer of oil and decrease its hotspot temperature. So that, the hotspot temperature of the Fe304/oil and graphene/oil were respectively 1 °C and 4.5 °C lower than that of the mineral oil. In addition, the transformer filled with graphene/oil nanofluid experienced considerably lower temperature in the thermally critical region. According to the obtained results, employing the nanofluid improves the cooling performance of the transformer, which leads to a more reliable operation and longer life.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129032395","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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