Pub Date : 2019-06-01DOI: 10.1109/EIC43217.2019.9046539
Benard M. Makaa, G. Irungu, D. Murage
Mineral insulating fluids have conventionally been used as insulating liquids in electrical equipment for over a century. These fluids serve as dielectrics and coolants. They are however known to be environmentally toxic and are highly flammable. Hence, they require costly fire protection schemes and deluge systems. Increasing awareness of environmental protection and fire safety is leading to accelerating trend of looking for plant based oil alternatives that are environmentally friendly. Increase in power rating of electrical equipment also calls for high temperature performance insulating oils. Plant based dielectric fluids have been found to defeat mineral oils in many of these aspects. They are nontoxic, possess better thermal properties and have excellent biodegradability. In order to reduce the adverse environmental impact and to improve the fire safety of transformers, there is an increasing demand for plant based insulating liquids as transformer insulating oils. This paper presents results of series of experiments that were performed to investigate the electrical, chemical, physical and thermal properties of food grade Persea americana ester (PAE) for possible use as insulation oil. For comparison, the corresponding properties of mineral insulation oil (MIO) in the same experimental conditions were also measured and compared with those of PAE. In this investigation, two different types of Persea americana oil samples consisting of extra virgin and refined PAE were tested. The obtained results show that the average electrical, chemical, physical and thermal properties of PAE meet the IEC and IEEE specifications for new natural liquid insulation oils. This may suggest that Persea americana oil can be tried as an alternative transformer liquid insulation.
{"title":"Investigation of Persea Americana Oil as an Alternative Transformer Insulation Oil","authors":"Benard M. Makaa, G. Irungu, D. Murage","doi":"10.1109/EIC43217.2019.9046539","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046539","url":null,"abstract":"Mineral insulating fluids have conventionally been used as insulating liquids in electrical equipment for over a century. These fluids serve as dielectrics and coolants. They are however known to be environmentally toxic and are highly flammable. Hence, they require costly fire protection schemes and deluge systems. Increasing awareness of environmental protection and fire safety is leading to accelerating trend of looking for plant based oil alternatives that are environmentally friendly. Increase in power rating of electrical equipment also calls for high temperature performance insulating oils. Plant based dielectric fluids have been found to defeat mineral oils in many of these aspects. They are nontoxic, possess better thermal properties and have excellent biodegradability. In order to reduce the adverse environmental impact and to improve the fire safety of transformers, there is an increasing demand for plant based insulating liquids as transformer insulating oils. This paper presents results of series of experiments that were performed to investigate the electrical, chemical, physical and thermal properties of food grade Persea americana ester (PAE) for possible use as insulation oil. For comparison, the corresponding properties of mineral insulation oil (MIO) in the same experimental conditions were also measured and compared with those of PAE. In this investigation, two different types of Persea americana oil samples consisting of extra virgin and refined PAE were tested. The obtained results show that the average electrical, chemical, physical and thermal properties of PAE meet the IEC and IEEE specifications for new natural liquid insulation oils. This may suggest that Persea americana oil can be tried as an alternative transformer liquid insulation.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"28 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":"126448041","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/EIC43217.2019.9046639
Nageshwar Rao Burjupati, R. Kandiban, C. Ashwin Parthsarathy
Influence of nano fillers like MgO, SiO2 and clay on the dielectric response of HVDC cable dielectric is investigated. Surface treated metal oxide MgO, metalloid SiO2nanoparticles and nano clay of different concentrations in low density polyethylene was considered for the study. LDPE-nano dielectric was prepared by using Brabender twin screw extruder and thin samples were obtained using hot plate vulcaniser. Electrical & dielectric properties were determined. The study indicated that, inclusion of nano fillers in the LDPE matrix resulted in an increase in contact angle and lower wetting energy of the composite. Surface potential decay was observed to be slow with composites indicating increased resistance to surface charge mobility. The relative permittivity and dielectric loss factor of nano dielectric increase with filler concentration and with decreased frequency. The polarization currents decrease exponentially with time and stabilize much lower than LDPE. The results are presented and discussed.
{"title":"Influence of Metal oxide and Metalloid Nano Particles on the Dielectric Response of HVDC Cable Nano Dielectric","authors":"Nageshwar Rao Burjupati, R. Kandiban, C. Ashwin Parthsarathy","doi":"10.1109/EIC43217.2019.9046639","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046639","url":null,"abstract":"Influence of nano fillers like MgO, SiO2 and clay on the dielectric response of HVDC cable dielectric is investigated. Surface treated metal oxide MgO, metalloid SiO2nanoparticles and nano clay of different concentrations in low density polyethylene was considered for the study. LDPE-nano dielectric was prepared by using Brabender twin screw extruder and thin samples were obtained using hot plate vulcaniser. Electrical & dielectric properties were determined. The study indicated that, inclusion of nano fillers in the LDPE matrix resulted in an increase in contact angle and lower wetting energy of the composite. Surface potential decay was observed to be slow with composites indicating increased resistance to surface charge mobility. The relative permittivity and dielectric loss factor of nano dielectric increase with filler concentration and with decreased frequency. The polarization currents decrease exponentially with time and stabilize much lower than LDPE. The results are presented and discussed.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"44 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":"127096906","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/EIC43217.2019.9046624
Zhuo Wei, Haoyang You, Boxue Hu, Risha Na, Jin Wang
The use of wide-bandgap (WBG) semiconductor device is increasing due to its capability to operate at much higher voltage, frequency and temperature compared with traditional semiconductor device. WBG semiconductor device is capable to generate voltages with ultra-high dv/dt (ultra-short rise time), which would alter the voltage stress in various electrical apparatus, e.g., inverter-controlled motors, and consequently change partial discharge (PD) behavior. Combine this with the fact that PD detection in inverter-controlled motor winding, even with slow-rising voltages, is intrinsically complicated, the study of PD behavior under ultra-fast squarewave voltages is much needed. In this paper, experimental observations and results for twisted pair samples stressed by an impulse generator with the ability of generating ultra-fast square-wave voltage are presented. Statements and hypotheses on PD behaviors and mechanism under ultra-fast dv/dt squarewave excitations are also put forward based on the test results.
{"title":"Partial Discharge Behavior on Twisted Pair under Ultra-short Rise Time Square-wave Excitations","authors":"Zhuo Wei, Haoyang You, Boxue Hu, Risha Na, Jin Wang","doi":"10.1109/EIC43217.2019.9046624","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046624","url":null,"abstract":"The use of wide-bandgap (WBG) semiconductor device is increasing due to its capability to operate at much higher voltage, frequency and temperature compared with traditional semiconductor device. WBG semiconductor device is capable to generate voltages with ultra-high dv/dt (ultra-short rise time), which would alter the voltage stress in various electrical apparatus, e.g., inverter-controlled motors, and consequently change partial discharge (PD) behavior. Combine this with the fact that PD detection in inverter-controlled motor winding, even with slow-rising voltages, is intrinsically complicated, the study of PD behavior under ultra-fast squarewave voltages is much needed. In this paper, experimental observations and results for twisted pair samples stressed by an impulse generator with the ability of generating ultra-fast square-wave voltage are presented. Statements and hypotheses on PD behaviors and mechanism under ultra-fast dv/dt squarewave excitations are also put forward based on the test results.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"20 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":"126700680","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/EIC43217.2019.9046611
K. Yamashita, T. Miyake, T. Sakoda, Wataru Kawano
At joint and terminal sections of the cross-linked polyethylene (XLPE) cable, partial discharges (PDs) occur in defects of insulating materials. The PD generation can occur at any points in the insulation system where electric field strength exceeds a PD inception electric field and can develop until breakdown occurs. That is, PDs which are owing to local electrical stress in the insulation or on the surface of the insulation reflect a kind of sign of insulation deterioration. Therefore, PD measurement is a useful technique of assessing the insulation deterioration of XLPE cables. For conventional systems to measure and locate PDs, the propagation velocity of PD pulse must be known. However, it likely depends on the aging deterioration of power cable and the number of joint sections. We therefore propose a partial discharge locator (PDL) system which has a time synchronization measure and a unique time generation measure based on LabVIEW. The PDL is possible to locate a PD occurrence position without power interruption. We here show how the PDL works with a time synchronization between detecting devices arranged at both sides of an XPLE cable to be measured. Additionally, it is investigated that the PD-position locating accuracy is within 10 %.
{"title":"Study on Location Accuracy of Partial Discharge Locator","authors":"K. Yamashita, T. Miyake, T. Sakoda, Wataru Kawano","doi":"10.1109/EIC43217.2019.9046611","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046611","url":null,"abstract":"At joint and terminal sections of the cross-linked polyethylene (XLPE) cable, partial discharges (PDs) occur in defects of insulating materials. The PD generation can occur at any points in the insulation system where electric field strength exceeds a PD inception electric field and can develop until breakdown occurs. That is, PDs which are owing to local electrical stress in the insulation or on the surface of the insulation reflect a kind of sign of insulation deterioration. Therefore, PD measurement is a useful technique of assessing the insulation deterioration of XLPE cables. For conventional systems to measure and locate PDs, the propagation velocity of PD pulse must be known. However, it likely depends on the aging deterioration of power cable and the number of joint sections. We therefore propose a partial discharge locator (PDL) system which has a time synchronization measure and a unique time generation measure based on LabVIEW. The PDL is possible to locate a PD occurrence position without power interruption. We here show how the PDL works with a time synchronization between detecting devices arranged at both sides of an XPLE cable to be measured. Additionally, it is investigated that the PD-position locating accuracy is within 10 %.","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":"131311101","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/EIC43217.2019.9046520
Y. Nishigaki, T. Matsuzoe, Tomohiro Kubo, Y. Nakano, M. Kozako, M. Hikita, Takahiro Nakamura, Jintong Sun, A. Izumi, Takavuki Sakurai, K. Karasawa, K. Nojima
Recently, driving of inverters has been advanced to improve the characteristics of motors. Along with that, concerns are raised that inverter surge deteriorates the insulation system of the motor. The problem of insulation deterioration is particularly serious in high-voltage motors where insulation structure is important, and analysis of phenomena of deterioration is strongly desired. We have measured repetitive partial discharge inception voltage (RPDIV) of an enamel twisted pair sample using a repetitive impulse voltage generator which can arbitrarily change the voltage value, pulse rise time and width, etc. This paper deals with RPDIV of a motorette that can simulate all connections in the motor (phase to phase, turn to turn, phase to ground) and investigates the influence of temperature on RPDIV characteristics. Measurements of RPDIV of the motorette with varnish treatment were also made in the temperature range between room temperature 25°C and 155°C. Experimental results revealed that the RPDIV for the phase to phase and turn to turn connection tends to decrease with increase in temperature. An attempt is made to interpret the temperature dependence of the RPDIV in terms of the temperature dependent pressure change in void defect which may exist in the vanish of the motorette.
{"title":"Temperature Dependence of RPDIV of Motorette Sample with Varnish Treatment","authors":"Y. Nishigaki, T. Matsuzoe, Tomohiro Kubo, Y. Nakano, M. Kozako, M. Hikita, Takahiro Nakamura, Jintong Sun, A. Izumi, Takavuki Sakurai, K. Karasawa, K. Nojima","doi":"10.1109/EIC43217.2019.9046520","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046520","url":null,"abstract":"Recently, driving of inverters has been advanced to improve the characteristics of motors. Along with that, concerns are raised that inverter surge deteriorates the insulation system of the motor. The problem of insulation deterioration is particularly serious in high-voltage motors where insulation structure is important, and analysis of phenomena of deterioration is strongly desired. We have measured repetitive partial discharge inception voltage (RPDIV) of an enamel twisted pair sample using a repetitive impulse voltage generator which can arbitrarily change the voltage value, pulse rise time and width, etc. This paper deals with RPDIV of a motorette that can simulate all connections in the motor (phase to phase, turn to turn, phase to ground) and investigates the influence of temperature on RPDIV characteristics. Measurements of RPDIV of the motorette with varnish treatment were also made in the temperature range between room temperature 25°C and 155°C. Experimental results revealed that the RPDIV for the phase to phase and turn to turn connection tends to decrease with increase in temperature. An attempt is made to interpret the temperature dependence of the RPDIV in terms of the temperature dependent pressure change in void defect which may exist in the vanish of the motorette.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"72 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":"132925998","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}
Oil-impregnated cellulose paper is the main insulation material used in power transformers. The thermal stability of cellulose insulation is important for the steady and safe operation of a transformer. The reinforcement of the thermal stability of cellulose via physical and chemical modification has attracted much research attention. Considering that traditional experiments are costly and time-consuming, molecular dynamics simulation is introduced to predict or estimate the performance of modified cellulose by calculating several key parameters. However, linking the model performance parameters with macroscopic properties of materials at the molecular simulation scale is difficult. In this study, two parameters, namely, mean square displacement (MSD) and glass transition temperature (Tg), are proposed to evaluate the thermal stability of cellulose. The validity of these two parameters to characterize the thermal stability of cellulose is verified by the simulation results from natural cellulose and acetylation-grafted cellulose models. In engineering application, acetylation-grafted cellulose performs better than natural cellulose in terms of thermal stability. According to the simulation results, the Tg of acetylation-grafted cellulose is approximately 111 K higher than that of natural cellulose. Compared with the natural cellulose, the MSD of acetylation-grafted cellulose considerably decreased, indicating that the intensity of movement for the acetylation-grafted cellulose chain is prominently smaller than the natural cellulose chain at every time step. These results also show that acetylation-grafted cellulose can improve the thermal stability of cellulose, which is consistent with previous studies.
{"title":"Estimating the Thermal Stability of Cellulose Insulation using MSD and Tg parameters by Molecular Dynamics Simulation","authors":"Wei Hou, Lijun Yang, Yang Mo, Tiantian Zou, Youyu Huang, Xiaoling Zheng","doi":"10.1109/EIC43217.2019.9046567","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046567","url":null,"abstract":"Oil-impregnated cellulose paper is the main insulation material used in power transformers. The thermal stability of cellulose insulation is important for the steady and safe operation of a transformer. The reinforcement of the thermal stability of cellulose via physical and chemical modification has attracted much research attention. Considering that traditional experiments are costly and time-consuming, molecular dynamics simulation is introduced to predict or estimate the performance of modified cellulose by calculating several key parameters. However, linking the model performance parameters with macroscopic properties of materials at the molecular simulation scale is difficult. In this study, two parameters, namely, mean square displacement (MSD) and glass transition temperature (Tg), are proposed to evaluate the thermal stability of cellulose. The validity of these two parameters to characterize the thermal stability of cellulose is verified by the simulation results from natural cellulose and acetylation-grafted cellulose models. In engineering application, acetylation-grafted cellulose performs better than natural cellulose in terms of thermal stability. According to the simulation results, the Tg of acetylation-grafted cellulose is approximately 111 K higher than that of natural cellulose. Compared with the natural cellulose, the MSD of acetylation-grafted cellulose considerably decreased, indicating that the intensity of movement for the acetylation-grafted cellulose chain is prominently smaller than the natural cellulose chain at every time step. These results also show that acetylation-grafted cellulose can improve the thermal stability of cellulose, which is consistent with previous studies.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"31 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":"132661207","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/EIC43217.2019.9046545
Xi Zhu, Jiandong Wu, Xinlong Zhen, Qiwei Bao, Chuansheng Zhang, Y. Yin
Isothermal relaxation current (IRC) method is a non-destruction evaluation method to measure the depolarization current in cable based on the dielectric response theory. In this paper, a modified IRC measurement technique is put forward to eliminate the current interference produced by test line. The equivalent circuit of XLPE cable with IRC system is built to analyze the relaxation current, and a modified measurement circuit is designed based on a method of independent measurement loop. The modified circuit can exclude the interference produced by test line from the measurement loop. By the use of the Multisim software, the difference among ideal current, current with interference and current acquired by the modified circuit is discussed, which demonstrates the feasibility and the validity of modified technique in theory. Furthermore, an IRC system is established, and a XLPE cable which has been aged thermally is detected by the IRC system. The results show that there are a lot of deep traps distributed in the aged cable insulation, which verifies the effectivity of the modified technique in practice.
{"title":"A Modified Measurement Technique Based on the Depolarization Current Used for Power Cable","authors":"Xi Zhu, Jiandong Wu, Xinlong Zhen, Qiwei Bao, Chuansheng Zhang, Y. Yin","doi":"10.1109/EIC43217.2019.9046545","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046545","url":null,"abstract":"Isothermal relaxation current (IRC) method is a non-destruction evaluation method to measure the depolarization current in cable based on the dielectric response theory. In this paper, a modified IRC measurement technique is put forward to eliminate the current interference produced by test line. The equivalent circuit of XLPE cable with IRC system is built to analyze the relaxation current, and a modified measurement circuit is designed based on a method of independent measurement loop. The modified circuit can exclude the interference produced by test line from the measurement loop. By the use of the Multisim software, the difference among ideal current, current with interference and current acquired by the modified circuit is discussed, which demonstrates the feasibility and the validity of modified technique in theory. Furthermore, an IRC system is established, and a XLPE cable which has been aged thermally is detected by the IRC system. The results show that there are a lot of deep traps distributed in the aged cable insulation, which verifies the effectivity of the modified technique in practice.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"44 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":"131104106","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/EIC43217.2019.9046555
Haoyang You, Zhuo Wei, Mohammed Aldawsari, Boxue Hu, Risha Na, Jin Wang
Partial discharge (PD) is more likely to happen in the power module due to the increasing switching speed of new generation semiconductors. However, little research has been done to study the PD behaviors under very fast dv/dt (above $50 mathrm{kV}/mumathrm{s}$) repetitive square-wave voltages. To address this problem, PD behaviors of designed direct bonded copper (DBC) samples with different trench distances and chamfer radiuses under fast dv/dt ($130 mathrm{kV}/mumathrm{s}$) repetitive square voltages are studied. The results show that, for different trench distances, the partial discharge inception voltage (PDIV) increases linearly with increasing trench distances when the chamfer radius is larger than 0.5 mm, while PDIV shows a hump curve when the chamfer radius is less than 0.5 mm. The apparent charge becomes 23 nC with a large dispersion when the trench distance is 0.5 mm. For different chamfer radiuses, PDIV presents a U-shape shape curve with increasing radiuses from the zero (right angle) to 0.7 mm. The apparent charge is about 325 pC with a large dispersion when the chamfer radius is zero. The detailed experiment results and discussions are presented in this paper.
{"title":"Partial Discharge Behaviors in Power Module under Very High Dv/dt Repetitive Square Voltages","authors":"Haoyang You, Zhuo Wei, Mohammed Aldawsari, Boxue Hu, Risha Na, Jin Wang","doi":"10.1109/EIC43217.2019.9046555","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046555","url":null,"abstract":"Partial discharge (PD) is more likely to happen in the power module due to the increasing switching speed of new generation semiconductors. However, little research has been done to study the PD behaviors under very fast dv/dt (above $50 mathrm{kV}/mumathrm{s}$) repetitive square-wave voltages. To address this problem, PD behaviors of designed direct bonded copper (DBC) samples with different trench distances and chamfer radiuses under fast dv/dt ($130 mathrm{kV}/mumathrm{s}$) repetitive square voltages are studied. The results show that, for different trench distances, the partial discharge inception voltage (PDIV) increases linearly with increasing trench distances when the chamfer radius is larger than 0.5 mm, while PDIV shows a hump curve when the chamfer radius is less than 0.5 mm. The apparent charge becomes 23 nC with a large dispersion when the trench distance is 0.5 mm. For different chamfer radiuses, PDIV presents a U-shape shape curve with increasing radiuses from the zero (right angle) to 0.7 mm. The apparent charge is about 325 pC with a large dispersion when the chamfer radius is zero. The detailed experiment results and discussions are presented in this paper.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"18 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":"116421835","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/EIC43217.2019.9046581
G. Callender, P. Lewin
This paper is a preliminary investigation into the physical mechanisms of PD within gaseous tubules in a needle-plane electrode arrangement. It is intended as a simple representation of an experimental system which formed electrical trees. A drift diffusion model is used to simulate plasma dynamics, where it is assumed that the gas within the tubule is atmospheric pressure air. The findings were in reasonable agreement with the existing literature on the tubule length required to initiate a PD. The PDs were found to be positive streamers, which propagated towards the needle tip at negative applied voltage polarity, and away from the needle tip at positive voltage polarity. There a number of possible developments for future work with the ultimate aim of improving simulations of electrical treeing in high voltage plant.
{"title":"Plasma Dynamic Simulations of Partial Discharges within Electrical Tree Structures","authors":"G. Callender, P. Lewin","doi":"10.1109/EIC43217.2019.9046581","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046581","url":null,"abstract":"This paper is a preliminary investigation into the physical mechanisms of PD within gaseous tubules in a needle-plane electrode arrangement. It is intended as a simple representation of an experimental system which formed electrical trees. A drift diffusion model is used to simulate plasma dynamics, where it is assumed that the gas within the tubule is atmospheric pressure air. The findings were in reasonable agreement with the existing literature on the tubule length required to initiate a PD. The PDs were found to be positive streamers, which propagated towards the needle tip at negative applied voltage polarity, and away from the needle tip at positive voltage polarity. There a number of possible developments for future work with the ultimate aim of improving simulations of electrical treeing in high voltage plant.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"23 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":"116445272","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/EIC43217.2019.9046635
J. Slater, I. Mitiche, A. Nesbitt, G. Morison, P. Boreham
On-line condition monitoring of substation electrical equipment depends on reliable, non-invasive surveillance techniques. Early detection of faults helps to mitigate the need for reactive maintenance and unplanned system downtime, thus ensuring continuity of supply. The Electro Magnetic Interference (EMI) method is a surveillance technique that can assist in identifying insulation degradation and conductor faults; such as Partial Discharge (PD) and Arcing. EMI frequency scans are used to identify the frequencies that are characteristic of fault conditions. Time-resolved analysis at these frequencies provides crucial data necessary for the classification of these faults. With the emergence of continuous on-line monitoring, there is an increasing need to embed more intelligence within monitoring devices to automatically recognise developing fault conditions. The main challenges faced with this method is that there is too much emphasis put on engineers in the field being able to identify these key frequencies by eye or knowledge alone, which limits the ability to automate the process. This paper presents a novel diagnostic assistant that will automatically identify the spot frequencies the engineer would manually capture for further, time-resolved analysis. The resultant time-resolved scans are then analysed to perform feature extraction and dimensionality reduction to automatically classify the data to a known fault category. Validation of the proposed techniques has been performed on real world data captured and labelled by engineers in the field. The accuracy of this method is established through direct comparison between the choices made by the engineers in the field to the classification of fault conditions and the decisions of the automated diagnostic assistant. The consistent accuracy of the results obtained paves the way for a fully automated expert system that can identify and classify possible emerging fault conditions utilising EMI diagnostics.
{"title":"Automated identification of insulation faults using Electro Magnetic Interference methods","authors":"J. Slater, I. Mitiche, A. Nesbitt, G. Morison, P. Boreham","doi":"10.1109/EIC43217.2019.9046635","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046635","url":null,"abstract":"On-line condition monitoring of substation electrical equipment depends on reliable, non-invasive surveillance techniques. Early detection of faults helps to mitigate the need for reactive maintenance and unplanned system downtime, thus ensuring continuity of supply. The Electro Magnetic Interference (EMI) method is a surveillance technique that can assist in identifying insulation degradation and conductor faults; such as Partial Discharge (PD) and Arcing. EMI frequency scans are used to identify the frequencies that are characteristic of fault conditions. Time-resolved analysis at these frequencies provides crucial data necessary for the classification of these faults. With the emergence of continuous on-line monitoring, there is an increasing need to embed more intelligence within monitoring devices to automatically recognise developing fault conditions. The main challenges faced with this method is that there is too much emphasis put on engineers in the field being able to identify these key frequencies by eye or knowledge alone, which limits the ability to automate the process. This paper presents a novel diagnostic assistant that will automatically identify the spot frequencies the engineer would manually capture for further, time-resolved analysis. The resultant time-resolved scans are then analysed to perform feature extraction and dimensionality reduction to automatically classify the data to a known fault category. Validation of the proposed techniques has been performed on real world data captured and labelled by engineers in the field. The accuracy of this method is established through direct comparison between the choices made by the engineers in the field to the classification of fault conditions and the decisions of the automated diagnostic assistant. The consistent accuracy of the results obtained paves the way for a fully automated expert system that can identify and classify possible emerging fault conditions utilising EMI diagnostics.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"50 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":"123164877","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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