Pub Date : 2019-06-01DOI: 10.1109/EIC43217.2019.9046562
S. Iwata, Ryota Kitani, T. Takada
The degradation of insulating property of polymeric materials was evaluated by the new diagnostic technique of current integration system, hereafter referred to as the “Q(t)-meter”. The Q(t)-meter measures the change with time in integrated charge accumulated by a capacitor inserted between a DC high-voltage power supply and a sample of the insulation material under study. Q(t)-meter is suitable for the monitoring of time dependence of leakage current of the insulating sample under DC voltage. To demonstrate the performance of this new device, we evaluated the influence of generation and propagation of “electrical tree” in epoxy resin sample on DC leakage current. The electrical tree is a typical electrical degradation of polymeric materials. Hence, nondestructive diagnostic methods for electrical tree are expected. In this study, the electrical tree was generated in the epoxy resin by AC high voltage between two needle electrodes. The interelectrode distance was 2 mm. In the Q(t) measurement, the sampling frequency, total sampling time, DC applied time, and test voltages were 2 s, 600 s, 900 s, 250-1,000 V, respectively. We conducted Q(t) measurement at three stages of electrical treeing - before tree generation, after tree generation, and after tree propagation. It was found that the leakage current increased with increase in the tree length. A remarkable trend of steep rise and fall in the Q(t) curve was also observed. Experimental results obtained by the Q(t)-meter were analyzed assuming an “RC circuit model”.
{"title":"Diagnostic Technique for Electrical Tree by Current Integration Method","authors":"S. Iwata, Ryota Kitani, T. Takada","doi":"10.1109/EIC43217.2019.9046562","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046562","url":null,"abstract":"The degradation of insulating property of polymeric materials was evaluated by the new diagnostic technique of current integration system, hereafter referred to as the “Q(t)-meter”. The Q(t)-meter measures the change with time in integrated charge accumulated by a capacitor inserted between a DC high-voltage power supply and a sample of the insulation material under study. Q(t)-meter is suitable for the monitoring of time dependence of leakage current of the insulating sample under DC voltage. To demonstrate the performance of this new device, we evaluated the influence of generation and propagation of “electrical tree” in epoxy resin sample on DC leakage current. The electrical tree is a typical electrical degradation of polymeric materials. Hence, nondestructive diagnostic methods for electrical tree are expected. In this study, the electrical tree was generated in the epoxy resin by AC high voltage between two needle electrodes. The interelectrode distance was 2 mm. In the Q(t) measurement, the sampling frequency, total sampling time, DC applied time, and test voltages were 2 s, 600 s, 900 s, 250-1,000 V, respectively. We conducted Q(t) measurement at three stages of electrical treeing - before tree generation, after tree generation, and after tree propagation. It was found that the leakage current increased with increase in the tree length. A remarkable trend of steep rise and fall in the Q(t) curve was also observed. Experimental results obtained by the Q(t)-meter were analyzed assuming an “RC circuit model”.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"9 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":"126386806","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/EIC43217.2019.9046547
W. McDermid, M. Partyka, T. Black
During the period of 1993–1995 Manitoba Hydro investigated the claim by a service provider that water trees could be detected and located in service aged medium voltage XLPE cables by means of time domain reflectometry (TDR) following conditioning of the cable dielectric with direct voltage. In order to avoid subsequent short time in-service failures, it was necessary to limit the conditioning voltage to 0.5 per-unit. With this restriction, no conditioning related surge impedance anomalies were found in cable that subsequently was determined as containing substantial vented water trees. However, it was established that the measurement of leakage current at 0.5 per-unit negative polarity direct voltage did correlate with the magnitude of subsequent 0.1 Hz breakdown voltage. Beginning in 2014 Manitoba Hydro has been assessing service aged medium voltage XLPE cables using Tangent Delta measurements at 0.1 Hz voltages in accordance with IEEE Std 400.2. However, the notion that water tress can be detected and located as a result of conditioning with direct voltage is still of interest as is indicated by publications that have appeared in the literature in recent years, but the related conditioning utilizes direct voltages in excess of 0.5 per-unit.
{"title":"Water Tree Detection in Medium Voltage XLPE Cables","authors":"W. McDermid, M. Partyka, T. Black","doi":"10.1109/EIC43217.2019.9046547","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046547","url":null,"abstract":"During the period of 1993–1995 Manitoba Hydro investigated the claim by a service provider that water trees could be detected and located in service aged medium voltage XLPE cables by means of time domain reflectometry (TDR) following conditioning of the cable dielectric with direct voltage. In order to avoid subsequent short time in-service failures, it was necessary to limit the conditioning voltage to 0.5 per-unit. With this restriction, no conditioning related surge impedance anomalies were found in cable that subsequently was determined as containing substantial vented water trees. However, it was established that the measurement of leakage current at 0.5 per-unit negative polarity direct voltage did correlate with the magnitude of subsequent 0.1 Hz breakdown voltage. Beginning in 2014 Manitoba Hydro has been assessing service aged medium voltage XLPE cables using Tangent Delta measurements at 0.1 Hz voltages in accordance with IEEE Std 400.2. However, the notion that water tress can be detected and located as a result of conditioning with direct voltage is still of interest as is indicated by publications that have appeared in the literature in recent years, but the related conditioning utilizes direct voltages in excess of 0.5 per-unit.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"102 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":"124105053","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/EIC43217.2019.9046633
Z. Ahmed, Mojtaba Rostaghi Chalaki, Kamran Yousfpour, J. Klüss
A multivariate time series analysis was performed for a system of several PD response variables, i.e. average charge, number of discharge pulses, average charge current, and largest repetitive discharge magnitude over the data acquisition period. Experimental lifelong PD data obtained from cable samples subjected to accelerated degradation was used to study the dynamic trends and relationships among those aforementioned response variables. Stochastically formulated cointegrated variables recognized by those tests can be combined to form new stationary variables to estimate the parameters for the Vector Auto Regression (VAR) and Vector-Error Correction (VEC) models. The validity of both models was evaluated by generating Monte Carlo and Minimum Mean Squared Error (MMSE) simulated forecasts. True observed data and forecasted data mean values lie within the 95th percentile confidence interval responses which demonstrates the soundness and accuracy of both models. A life-predicting model based on the cointegrating relations between the multiple response variables, correlated with experimentally evaluated time-to-breakdown values, can be used to set an emergent alarming trigger and as a step towards establishing long-term continuous monitoring of partial discharge activity.
{"title":"Multivariate Time Series Modeling for Long Term Partial Discharge Measurements in Medium Voltage XLPE Cables","authors":"Z. Ahmed, Mojtaba Rostaghi Chalaki, Kamran Yousfpour, J. Klüss","doi":"10.1109/EIC43217.2019.9046633","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046633","url":null,"abstract":"A multivariate time series analysis was performed for a system of several PD response variables, i.e. average charge, number of discharge pulses, average charge current, and largest repetitive discharge magnitude over the data acquisition period. Experimental lifelong PD data obtained from cable samples subjected to accelerated degradation was used to study the dynamic trends and relationships among those aforementioned response variables. Stochastically formulated cointegrated variables recognized by those tests can be combined to form new stationary variables to estimate the parameters for the Vector Auto Regression (VAR) and Vector-Error Correction (VEC) models. The validity of both models was evaluated by generating Monte Carlo and Minimum Mean Squared Error (MMSE) simulated forecasts. True observed data and forecasted data mean values lie within the 95th percentile confidence interval responses which demonstrates the soundness and accuracy of both models. A life-predicting model based on the cointegrating relations between the multiple response variables, correlated with experimentally evaluated time-to-breakdown values, can be used to set an emergent alarming trigger and as a step towards establishing long-term continuous monitoring of partial discharge activity.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"53 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":"121821797","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/EIC43217.2019.9046542
P. Cheetham, Chanyeop Park, S. Satyanarayana, C. Kim, L. Graber, S. Pamidi
The concept of gas-insulated high temperature superconducting (HTS) coaxial dipole for power distribution systems in medium voltage direct current (MVDC) architectures is explored. Finite element analysis of electromagnetic characteristics of the preliminary designs of the HTS coaxial dipole show promise in terms of its ability to eliminate electromagnetic interference with other devices by eliminating the magnetic field leakage external to the dipole. The coaxial dipole allows effective cancelation of self-magnetic field of the individual poles carrying several kA current thus allowing higher current carrying capacity of the cable. Design options for arranging the HTS conductors and insulator spacers is presented. Outstanding challenges to realize practical coaxial dipole configurations of HTS power distribution systems are discussed.
{"title":"Gas-Insulated High Temperature Superconducting Coaxial Dipole for MVDC Power Systems","authors":"P. Cheetham, Chanyeop Park, S. Satyanarayana, C. Kim, L. Graber, S. Pamidi","doi":"10.1109/EIC43217.2019.9046542","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046542","url":null,"abstract":"The concept of gas-insulated high temperature superconducting (HTS) coaxial dipole for power distribution systems in medium voltage direct current (MVDC) architectures is explored. Finite element analysis of electromagnetic characteristics of the preliminary designs of the HTS coaxial dipole show promise in terms of its ability to eliminate electromagnetic interference with other devices by eliminating the magnetic field leakage external to the dipole. The coaxial dipole allows effective cancelation of self-magnetic field of the individual poles carrying several kA current thus allowing higher current carrying capacity of the cable. Design options for arranging the HTS conductors and insulator spacers is presented. Outstanding challenges to realize practical coaxial dipole configurations of HTS power distribution systems are discussed.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"15 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":"129513072","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/EIC43217.2019.9046521
A. Cavallini, Luca Lusardi, A. Rumi, K. Kimura, A. Contin, T. Han
Partial discharge testing of complete, low voltage induction machines using the configurations proposed in the IEC 60034-27-5CD, is discussed. Based on tests performed on a machine with accessible coil terminals, the most promising configurations for type tests and quality control, is proposed and the limits of the IEC 60034-18-41 highlighted.
{"title":"Searching for Optimal Connection Schemes for Partial Discharge Testing of Inverter-Fed Rotating Machines","authors":"A. Cavallini, Luca Lusardi, A. Rumi, K. Kimura, A. Contin, T. Han","doi":"10.1109/EIC43217.2019.9046521","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046521","url":null,"abstract":"Partial discharge testing of complete, low voltage induction machines using the configurations proposed in the IEC 60034-27-5CD, is discussed. Based on tests performed on a machine with accessible coil terminals, the most promising configurations for type tests and quality control, is proposed and the limits of the IEC 60034-18-41 highlighted.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"39 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":"133526568","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/EIC43217.2019.9046637
C. Mackinnon, B. Stewart
High voltage capacitors are becoming ever more prevalent on modern electrical power networks, as they offer simple means of power factor correction and voltage support, and are inherent to modern power electronic converter designs. Large capacitor banks comprise many modules, each of which contains an array of individual elements, across which voltage stresses and thermal conditions are shared. A module's partial degradation due to short-circuited elements can increase stresses on the insulation of those that remain, sometimes leading to cascading element failure. This paper presents a high voltage capacitor model, and then explores the distribution of voltage under healthy and short-circuit scenarios. It shows voltage distributions between elements within a capacitor module have nonlinearity due to a module's geometry, and are affected by series element failure.
{"title":"A High Voltage Capacitor Element Model","authors":"C. Mackinnon, B. Stewart","doi":"10.1109/EIC43217.2019.9046637","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046637","url":null,"abstract":"High voltage capacitors are becoming ever more prevalent on modern electrical power networks, as they offer simple means of power factor correction and voltage support, and are inherent to modern power electronic converter designs. Large capacitor banks comprise many modules, each of which contains an array of individual elements, across which voltage stresses and thermal conditions are shared. A module's partial degradation due to short-circuited elements can increase stresses on the insulation of those that remain, sometimes leading to cascading element failure. This paper presents a high voltage capacitor model, and then explores the distribution of voltage under healthy and short-circuit scenarios. It shows voltage distributions between elements within a capacitor module have nonlinearity due to a module's geometry, and are affected by series element failure.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"305 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":"131427027","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/EIC43217.2019.9046536
R. Acheen, C. Abadie, T. Billard, T. Lebey, S. Duchesne
Voltage inverters based on the pulse width modulation are widely used for applications that require controlling rotation speed. The devices used today to create pulse width modulation are Silicon (Si) IGBTs. The use of IGBTs enables to generate rising edges of tens of kV /µs, and to reach switching frequencies around 20 kHz. These improvements have helped to reduce switching losses and motor torque ripple. On the other hand, the reliability of motors has declined dramatically. The causes of motor failures may be due to different phenomena, but one of the main ageing mechanisms is the erosion of the different insulation materials induced by Partial Discharges (PD). For high voltage, high power and/or high frequency applications, silicon carbide (SiC) based components will in most of the case replace the current silicon-based components. If some works have already been achieved for on-line PD detection in low voltage motors fed by inverters using Si-IGBT technology, works are now needed when SiC-based components are used. For motors fed by low voltage, PDs mainly occur during the voltage edge. It is therefore necessary to discriminate them from the noise induced by switchings. The use of high pass filters proved its effectiveness for IGBTs but the use of SiC MOSFET will result in an increase of switching speed and consequently an increase of the noise frequency. For such conditions, it may be difficult to differentiate partial discharges from noise. This paper presents a study on the partial discharge inception voltage, on the ability to detect partial discharges and on the voltage stresses in motors supplied by SiC-MOSFET and Si-IGBT inverters. These results are discussed and possible strategies are proposed.
{"title":"Study of partial discharge detection in motors fed by SiC MOSFET and Si IGBT inverters","authors":"R. Acheen, C. Abadie, T. Billard, T. Lebey, S. Duchesne","doi":"10.1109/EIC43217.2019.9046536","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046536","url":null,"abstract":"Voltage inverters based on the pulse width modulation are widely used for applications that require controlling rotation speed. The devices used today to create pulse width modulation are Silicon (Si) IGBTs. The use of IGBTs enables to generate rising edges of tens of kV /µs, and to reach switching frequencies around 20 kHz. These improvements have helped to reduce switching losses and motor torque ripple. On the other hand, the reliability of motors has declined dramatically. The causes of motor failures may be due to different phenomena, but one of the main ageing mechanisms is the erosion of the different insulation materials induced by Partial Discharges (PD). For high voltage, high power and/or high frequency applications, silicon carbide (SiC) based components will in most of the case replace the current silicon-based components. If some works have already been achieved for on-line PD detection in low voltage motors fed by inverters using Si-IGBT technology, works are now needed when SiC-based components are used. For motors fed by low voltage, PDs mainly occur during the voltage edge. It is therefore necessary to discriminate them from the noise induced by switchings. The use of high pass filters proved its effectiveness for IGBTs but the use of SiC MOSFET will result in an increase of switching speed and consequently an increase of the noise frequency. For such conditions, it may be difficult to differentiate partial discharges from noise. This paper presents a study on the partial discharge inception voltage, on the ability to detect partial discharges and on the voltage stresses in motors supplied by SiC-MOSFET and Si-IGBT inverters. These results are discussed and possible strategies are proposed.","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":"130426461","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/EIC43217.2019.9046584
Sang Bin Lee, Alireza Naeini, S. Jayaram, G. Stone, M. Šašić
IEC 60034-18-41 has been developed as a standard acceptance test to ensure partial discharge (PD)-free operation for improving the reliability of low voltage (LV) variable frequency drive (VFD) motors. Although the test can verify whether PD exists in the stator for a voltage surge with predetermined magnitude and risetime, the information on where PD activity is occurring in the stator insulation is not clearly given. In this paper, a method based on variable risetime surge voltage testing is proposed for identifying the component of the stator insulation system where PD occurs in LV random wound motor stators (turn, phase, or ground insulation). This information can be used for increasing the PD inception voltage for improving the reliability of the motor through insulation system design/manufacturing. The test is implemented with a 4.5 kV variable risetime surge generator prototype. 4 LV ac motors are tested to show where PD is likely to occur in commercial LV motors.
{"title":"Impulse Voltage-based Test Method for Identifying the Stator Insulation Component with PD Activity for Low Voltage AC Motors","authors":"Sang Bin Lee, Alireza Naeini, S. Jayaram, G. Stone, M. Šašić","doi":"10.1109/EIC43217.2019.9046584","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046584","url":null,"abstract":"IEC 60034-18-41 has been developed as a standard acceptance test to ensure partial discharge (PD)-free operation for improving the reliability of low voltage (LV) variable frequency drive (VFD) motors. Although the test can verify whether PD exists in the stator for a voltage surge with predetermined magnitude and risetime, the information on where PD activity is occurring in the stator insulation is not clearly given. In this paper, a method based on variable risetime surge voltage testing is proposed for identifying the component of the stator insulation system where PD occurs in LV random wound motor stators (turn, phase, or ground insulation). This information can be used for increasing the PD inception voltage for improving the reliability of the motor through insulation system design/manufacturing. The test is implemented with a 4.5 kV variable risetime surge generator prototype. 4 LV ac motors are tested to show where PD is likely to occur in commercial LV motors.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"11 21 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":"115969966","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/EIC43217.2019.9046530
T. Matsuzoe, N. Kita, Y. Nishigaki, Tsuyoshi Abe, Tomohiro Kubo, Y. Nakano, M. Kozako, M. Hikita, N. Fujimoto, N. Hayashizaka, S. Fujimoto, Toshihiko Kato
In recent years, small and medium size generators are used as engine generators. The authors aim to develop enamelled wire that exceeds conventional resin insulation lifetime. Among nanocomposite materials, boehmite-based materials are reported to have a longer lifetime than silica-based materials, and they are expected as new insulating materials for enamel wire insulation layer. In this paper, we report on the effect of boehmite filler on dielectric properties and AC conductivity by acquiring complex permittivity and AC conductivity of a film sample with nano-boehmite alumina added to polyimide resin compared with those of samples with silica nano-fillers and without nano-fillers. As a result, it is suggested that the ionic carrier is more likely to move in the polyimide sample with AIOOH filler than in the neat sample in the high temperature region of 180 °C. From the above results, it is considered that the conductivity and the relative permittivity increase in the high temperature and low frequency region are due to the influence of crystal water of boehmite. In addition, measurements of life time of enamel twisted pair samples coated with polyimide filled with boehmite alumina nano-filliers were also made with comparison to that of samples without the boehmite alumina fillers.
{"title":"Dielectric and Insulation Properties of Polyimide-based Boehmite Nanocomposite Material","authors":"T. Matsuzoe, N. Kita, Y. Nishigaki, Tsuyoshi Abe, Tomohiro Kubo, Y. Nakano, M. Kozako, M. Hikita, N. Fujimoto, N. Hayashizaka, S. Fujimoto, Toshihiko Kato","doi":"10.1109/EIC43217.2019.9046530","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046530","url":null,"abstract":"In recent years, small and medium size generators are used as engine generators. The authors aim to develop enamelled wire that exceeds conventional resin insulation lifetime. Among nanocomposite materials, boehmite-based materials are reported to have a longer lifetime than silica-based materials, and they are expected as new insulating materials for enamel wire insulation layer. In this paper, we report on the effect of boehmite filler on dielectric properties and AC conductivity by acquiring complex permittivity and AC conductivity of a film sample with nano-boehmite alumina added to polyimide resin compared with those of samples with silica nano-fillers and without nano-fillers. As a result, it is suggested that the ionic carrier is more likely to move in the polyimide sample with AIOOH filler than in the neat sample in the high temperature region of 180 °C. From the above results, it is considered that the conductivity and the relative permittivity increase in the high temperature and low frequency region are due to the influence of crystal water of boehmite. In addition, measurements of life time of enamel twisted pair samples coated with polyimide filled with boehmite alumina nano-filliers were also made with comparison to that of samples without the boehmite alumina fillers.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"93 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":"125502516","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/EIC43217.2019.9046587
G. Montanari, R. Hebner, P. Seri, R. Ghosh
Partial discharge (PD) detection is a fundamental test for the design and diagnosis of insulation systems, particularly organic materials which must operate throughout their whole life without PD. The measurement of Partial Discharge Inception Voltage (PDIV) and Repetitive Partial Discharge Inception Voltage (RPDIV), the latter defined for power electronic-type supply, is therefore a key issue for the design and qualification tests of Type I insulation system of rotating machines fed by power converters. While experience and technology for PD inception measurements under sinusoidal voltage supply is well established, the same does not hold under repetitive-pulse voltage waveforms, such as those provided by inverters. In addition, electromagnetic noise generated by electronic switch commutation can overlap with PD pulses signals and this is even more cumbersome when fast rise-time components are employed, such as GaN or SiC semiconductors. Moreover, this is also the condition which is the most stressful for stator wire insulation. This work investigates methods to detect PD pulses on enameled wires, rejecting noise efficiently, under repetitive impulsive voltages with different rise times, from 60 ns to 1000 ns. The proposed techniques can be implemented to achieve un-supervised noise rejection, which would be an important goal for both off-line and on-line PD testing.
{"title":"Noise rejection and partial discharge identification in PDIV tests of insulated wires under repetitive impulse supply voltage","authors":"G. Montanari, R. Hebner, P. Seri, R. Ghosh","doi":"10.1109/EIC43217.2019.9046587","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046587","url":null,"abstract":"Partial discharge (PD) detection is a fundamental test for the design and diagnosis of insulation systems, particularly organic materials which must operate throughout their whole life without PD. The measurement of Partial Discharge Inception Voltage (PDIV) and Repetitive Partial Discharge Inception Voltage (RPDIV), the latter defined for power electronic-type supply, is therefore a key issue for the design and qualification tests of Type I insulation system of rotating machines fed by power converters. While experience and technology for PD inception measurements under sinusoidal voltage supply is well established, the same does not hold under repetitive-pulse voltage waveforms, such as those provided by inverters. In addition, electromagnetic noise generated by electronic switch commutation can overlap with PD pulses signals and this is even more cumbersome when fast rise-time components are employed, such as GaN or SiC semiconductors. Moreover, this is also the condition which is the most stressful for stator wire insulation. This work investigates methods to detect PD pulses on enameled wires, rejecting noise efficiently, under repetitive impulsive voltages with different rise times, from 60 ns to 1000 ns. The proposed techniques can be implemented to achieve un-supervised noise rejection, which would be an important goal for both off-line and on-line PD testing.","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":"125845869","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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