Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158728
A. Greco, J. O. Rossi, F. S. Yamasaki, J. Barroso, E. Schamiloglu, Lauro Paulo da Silva Neto
Ferrite-charged nonlinear transmission lines (NLTLs) have been used as electromagnetic shock lines in applications that require pulses with extremely fast rise times. Subject to an intense external magnetic field (20–40 kA/m), these lines can generate microwave radiation generally in L-band (1–2 GHz) and are known in this case as nonlinear gyromagnetic lines. Due to its wide applicability in the RF area, such as electronic warfare (in defense) or high power beam modulators (in industry), there is growing interest in the study of these lines, especially using finite difference time domain (FDTD) simulations to predict some important line parameters, such as the rise time of the output pulse and the frequency generated. The FDTD method is based on the nonlinear behavior of the magnetic material that fills the line as the current pulse propagates, inducing RF oscillations due to the precession of the ferrite's magnetic moments, described mathematically by the Landau-Lifshitz-Gilbert equation (LLG). Thus, this work presents a one-dimensional numerical modeling and simulation (1D) study to describe the behavior of these lines, which operate in the TEM mode. The numerical simulations were obtained using the joint solution of the transmission line equations and the gyromagnetic LLG equation in the publicly available software OCTAVE.
{"title":"1D-FDTD Simulation of Microwave Generation Using Ferrite Electromagnetic Shock Lines","authors":"A. Greco, J. O. Rossi, F. S. Yamasaki, J. Barroso, E. Schamiloglu, Lauro Paulo da Silva Neto","doi":"10.1109/eic47619.2020.9158728","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158728","url":null,"abstract":"Ferrite-charged nonlinear transmission lines (NLTLs) have been used as electromagnetic shock lines in applications that require pulses with extremely fast rise times. Subject to an intense external magnetic field (20–40 kA/m), these lines can generate microwave radiation generally in L-band (1–2 GHz) and are known in this case as nonlinear gyromagnetic lines. Due to its wide applicability in the RF area, such as electronic warfare (in defense) or high power beam modulators (in industry), there is growing interest in the study of these lines, especially using finite difference time domain (FDTD) simulations to predict some important line parameters, such as the rise time of the output pulse and the frequency generated. The FDTD method is based on the nonlinear behavior of the magnetic material that fills the line as the current pulse propagates, inducing RF oscillations due to the precession of the ferrite's magnetic moments, described mathematically by the Landau-Lifshitz-Gilbert equation (LLG). Thus, this work presents a one-dimensional numerical modeling and simulation (1D) study to describe the behavior of these lines, which operate in the TEM mode. The numerical simulations were obtained using the joint solution of the transmission line equations and the gyromagnetic LLG equation in the publicly available software OCTAVE.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115500535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/EIC47619.2020.9158768
M. Tousi, M. Ghassemi
As shown in our previous studies, geometrical field grading techniques such as stacked and protruding substrate designs cannot well mitigate high electric stress issue within power electronics modules. However, it was shown that a combination of protruding substrate design and applying a nonlinear field-dependent conductivity layer could address the issue. Electric filed (E) simulations were carried out according to IEC 61287-1 for the partial discharge test measurement step, where a 50/60 Hz AC voltage was applied. However, dielectrics, including ceramic substrate and silicone gel, in power devices undergo high temperatures up to a few hundred degrees and frequencies up to 1 MHz. Thus, E values obtained with electrical parameters of the mentioned dielectrics for room temperature and under 50/60 Hz may not be valid for high temperatures and frequencies mentioned above. In this paper, we address this technical gap through developing a finite element method (FEM) E calculation model developed in COMSOL Multiphysics where E calculations are carried out for different temperatures up to 250°C and frequencies up to 1 MHz. Using the model, the influence of temperature and frequency on our proposed electric field mitigation technique mentioned above is evaluated.
{"title":"Influence of Temperature and Frequency on Electric Field Reduction Method via a Nonlinear Field Dependent Conductivity Layer Combined with Protruding Substrate for Power Electronics Modules","authors":"M. Tousi, M. Ghassemi","doi":"10.1109/EIC47619.2020.9158768","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158768","url":null,"abstract":"As shown in our previous studies, geometrical field grading techniques such as stacked and protruding substrate designs cannot well mitigate high electric stress issue within power electronics modules. However, it was shown that a combination of protruding substrate design and applying a nonlinear field-dependent conductivity layer could address the issue. Electric filed (E) simulations were carried out according to IEC 61287-1 for the partial discharge test measurement step, where a 50/60 Hz AC voltage was applied. However, dielectrics, including ceramic substrate and silicone gel, in power devices undergo high temperatures up to a few hundred degrees and frequencies up to 1 MHz. Thus, E values obtained with electrical parameters of the mentioned dielectrics for room temperature and under 50/60 Hz may not be valid for high temperatures and frequencies mentioned above. In this paper, we address this technical gap through developing a finite element method (FEM) E calculation model developed in COMSOL Multiphysics where E calculations are carried out for different temperatures up to 250°C and frequencies up to 1 MHz. Using the model, the influence of temperature and frequency on our proposed electric field mitigation technique mentioned above is evaluated.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116662626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/EIC47619.2020.9158750
T. Gaerke, N. Lang
Surge testing of stator windings has long been used as part of incoming testing for inspections and documentation for machines with periodic maintenance plans. While IEEE 522 and IEC 60034–15 offer some guidance for performing the test on windings and windings which have been aged, neither offers acceptable results when comparing resulting wave forms from different phases or technical explanations to problems. It is known steep front rise time surge comparisons only applies electrical stress the first few turns of the first coil or coils in a phase and may not be useful in checking the dielectric performance past the first coil. This paper will explain an experience which surge comparison was used as part of an incoming test plan, the questionable comparison results, the issue, remediation, corrected results, and a proposal for suggested acceptable separation of resulting waveform between phases
{"title":"A Problematic Field Experience Using Surge Testing","authors":"T. Gaerke, N. Lang","doi":"10.1109/EIC47619.2020.9158750","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158750","url":null,"abstract":"Surge testing of stator windings has long been used as part of incoming testing for inspections and documentation for machines with periodic maintenance plans. While IEEE 522 and IEC 60034–15 offer some guidance for performing the test on windings and windings which have been aged, neither offers acceptable results when comparing resulting wave forms from different phases or technical explanations to problems. It is known steep front rise time surge comparisons only applies electrical stress the first few turns of the first coil or coils in a phase and may not be useful in checking the dielectric performance past the first coil. This paper will explain an experience which surge comparison was used as part of an incoming test plan, the questionable comparison results, the issue, remediation, corrected results, and a proposal for suggested acceptable separation of resulting waveform between phases","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"41 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125882488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158751
A. Jahromi, Pranav Pattabi, Shanon Lo, J. Densley
Medium voltage (MV) polymeric cables are critical assets in modern power systems, since their introduction, approximately five decades ago. More recently, there has been a growing emphasis on the maintenance testing of polymeric cables, with some of them being prone to premature failures. This paper covers the various techniques available for the forensic failure investigation of polymeric cables through practical examples. Some of these include diagnostic electrical tests such as Insulation Resistance, AC Hipot & PD, and nonelectrical procedures such as visual inspection, optical microscopy, and differential scanning calorimetry (DSC). The recommended order of performing these techniques is also presented, based on the suspected failure mode. This serves as a practical guideline for utilities, towards identifying the type of cable failure sustained in the field. Diagnostic electrical testing (post-failure) helps establish the most probable cause of failure associated with polymeric cables and/or their accessories. A very useful, but less explored technique in polymer morphology is the DSC, which can be used to reveal the thermal history of a polymeric cable since its processing. In this regard, a detailed case study is presented to highlight the use of a DSC thermogram for determining the maximum temperature experienced by a polymeric cable and the potential source of heat.
{"title":"Approaches to the forensic failure investigation of medium voltage polymeric cables","authors":"A. Jahromi, Pranav Pattabi, Shanon Lo, J. Densley","doi":"10.1109/eic47619.2020.9158751","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158751","url":null,"abstract":"Medium voltage (MV) polymeric cables are critical assets in modern power systems, since their introduction, approximately five decades ago. More recently, there has been a growing emphasis on the maintenance testing of polymeric cables, with some of them being prone to premature failures. This paper covers the various techniques available for the forensic failure investigation of polymeric cables through practical examples. Some of these include diagnostic electrical tests such as Insulation Resistance, AC Hipot & PD, and nonelectrical procedures such as visual inspection, optical microscopy, and differential scanning calorimetry (DSC). The recommended order of performing these techniques is also presented, based on the suspected failure mode. This serves as a practical guideline for utilities, towards identifying the type of cable failure sustained in the field. Diagnostic electrical testing (post-failure) helps establish the most probable cause of failure associated with polymeric cables and/or their accessories. A very useful, but less explored technique in polymer morphology is the DSC, which can be used to reveal the thermal history of a polymeric cable since its processing. In this regard, a detailed case study is presented to highlight the use of a DSC thermogram for determining the maximum temperature experienced by a polymeric cable and the potential source of heat.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114469839","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}
In this paper, two studies are presented whose main objective is to go further on the comprehension of thermally upgraded paper ageing. The first one is about the accelerated ageing of standard (STD) and thermally upgraded (TU) Kraft paper in mineral oil. After plotting the viscometric degree of polymerization (DPv) according to the kinetic model proposed by Calvini in 2005 [1], the model is validated for STD paper but not for T U paper. A modification of this model for T U paper is suggested to improve the correlation with experimental data. In the second part, a study is presented on the investigation of the effect of a nitrogen-based additive (DICY) concentration on the paper ageing in oil. The DPv results confirm the protective effect of the DICY on the cellulose chains and show that this effect depends on the nitrogen content, but not linearly. The pH of aqueous extracts and surface FTIR analysis brought new support for a hypothesis regarding the functioning mechanisms of the DICY that are reported in the literature.
在本文中，提出了两项研究，其主要目的是进一步了解热升级纸老化。第一个是关于标准(STD)和热升级(TU)牛皮纸在矿物油中的加速老化。根据Calvini(2005)[1]提出的动力学模型绘制聚合度(viscomical degree of polymerization, DPv)后，该模型对STD纸进行了验证，但未对T U纸进行验证。本文建议对该模型进行修正，以提高与实验数据的相关性。第二部分研究了氮基添加剂(DICY)浓度对纸张在油液中老化的影响。DPv结果证实了DICY对纤维素链的保护作用，并表明这种作用与氮含量有关，但不是线性的。水提取物的pH值和表面FTIR分析为文献中报道的关于DICY功能机制的假设提供了新的支持。
{"title":"Novel investigations on ageing behaviour of thermally upgraded papers for power transformers","authors":"B. Axelle, Mortha Gérard, Marlin Nathalie, Boiron Lucie, Ramousse Agnès, Brun Huguette","doi":"10.1109/eic47619.2020.9158663","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158663","url":null,"abstract":"In this paper, two studies are presented whose main objective is to go further on the comprehension of thermally upgraded paper ageing. The first one is about the accelerated ageing of standard (STD) and thermally upgraded (TU) Kraft paper in mineral oil. After plotting the viscometric degree of polymerization (DPv) according to the kinetic model proposed by Calvini in 2005 [1], the model is validated for STD paper but not for T U paper. A modification of this model for T U paper is suggested to improve the correlation with experimental data. In the second part, a study is presented on the investigation of the effect of a nitrogen-based additive (DICY) concentration on the paper ageing in oil. The DPv results confirm the protective effect of the DICY on the cellulose chains and show that this effect depends on the nitrogen content, but not linearly. The pH of aqueous extracts and surface FTIR analysis brought new support for a hypothesis regarding the functioning mechanisms of the DICY that are reported in the literature.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122089179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158716
Jia Wei, Chanyeop Park, N. Uzelac, L. Graber
Although the breakdown strength and partial discharge characteristics between sulfur hexafluoride (SF6) and perfluoro-nitrile (C4F7N) have been reported in the literature, the study of aging and decomposition under low energy corona activity, and in particular, the potential deterioration of the dielectric properties have not been investigated yet. Since gas discharge is expected to result in the dissociation of the original gas species and recombine into other gaseous compounds, dielectric properties can exhibit significant deviation from the original gas. Therefore, it is crucial to understand the aging process and the impact of corona discharge on the physical properties of insulation gases. This paper summarizes and compares the decomposition characteristics of SF6 and C4F7N based on existing literature. Furthermore, an experimental setup proposed to study the decomposition product of SF6 and C4F7N under low energy corona activity is described. The objective of this paper is to evaluate the possibility and feasibility of using C4F7N to replace SF6 as an insulation gas in future power applications.
{"title":"Analysis of Decomposition Products of SF6 and C4F7N under Low Energy Corona Discharge","authors":"Jia Wei, Chanyeop Park, N. Uzelac, L. Graber","doi":"10.1109/eic47619.2020.9158716","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158716","url":null,"abstract":"Although the breakdown strength and partial discharge characteristics between sulfur hexafluoride (SF<inf>6</inf>) and perfluoro-nitrile (C<inf>4</inf>F<inf>7</inf>N) have been reported in the literature, the study of aging and decomposition under low energy corona activity, and in particular, the potential deterioration of the dielectric properties have not been investigated yet. Since gas discharge is expected to result in the dissociation of the original gas species and recombine into other gaseous compounds, dielectric properties can exhibit significant deviation from the original gas. Therefore, it is crucial to understand the aging process and the impact of corona discharge on the physical properties of insulation gases. This paper summarizes and compares the decomposition characteristics of SF<inf>6</inf> and C<inf>4</inf>F<inf>7</inf>N based on existing literature. Furthermore, an experimental setup proposed to study the decomposition product of SF<inf>6</inf> and C<inf>4</inf>F<inf>7</inf>N under low energy corona activity is described. The objective of this paper is to evaluate the possibility and feasibility of using C<inf>4</inf>F<inf>7</inf>N to replace SF<inf>6</inf> as an insulation gas in future power applications.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"219 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122153035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158699
C. Guo, Zhi Yang, Heli Ni, Rui Zhang, Yi Zhao, M. Jin, Qiaogen Zhang
Oil immersed inverted current transformer is vulnerable to overvoltage in the transmission line during operation. The accumulative effect of switching impulse voltage can degrade the main insulation and lead to a reduction in insulating property. In order to investigate the deterioration characteristic of main insulation of oil immersed inverted current transformer under the accumulative effect of switching impulse voltage and indicate the insulation deterioration, we studied the E-N characteristic of oil-paper insulation with different thickness and gave corresponding semi-empirical formulation to characterize the deterioration characteristic of main insulation of oil immersed inverted current transformer. The influence of insulation thickness on insulation deterioration of oil paper was studied as well. The results show that, the oil-paper insulation has a significant accumulative effect under switching impulse voltage. The E-N characteristic of oil-paper insulation conforms to power exponential distribution. With the increase of insulation thickness, the single minimum breakdown electric field strength decreases gradually.
{"title":"Effect of Insulation Thickness on Deterioration Characteristics of Oil-Paper Insulation under Switching Impulse Voltage","authors":"C. Guo, Zhi Yang, Heli Ni, Rui Zhang, Yi Zhao, M. Jin, Qiaogen Zhang","doi":"10.1109/eic47619.2020.9158699","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158699","url":null,"abstract":"Oil immersed inverted current transformer is vulnerable to overvoltage in the transmission line during operation. The accumulative effect of switching impulse voltage can degrade the main insulation and lead to a reduction in insulating property. In order to investigate the deterioration characteristic of main insulation of oil immersed inverted current transformer under the accumulative effect of switching impulse voltage and indicate the insulation deterioration, we studied the E-N characteristic of oil-paper insulation with different thickness and gave corresponding semi-empirical formulation to characterize the deterioration characteristic of main insulation of oil immersed inverted current transformer. The influence of insulation thickness on insulation deterioration of oil paper was studied as well. The results show that, the oil-paper insulation has a significant accumulative effect under switching impulse voltage. The E-N characteristic of oil-paper insulation conforms to power exponential distribution. With the increase of insulation thickness, the single minimum breakdown electric field strength decreases gradually.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129957195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158733
Jia Wei, A. Cruz, Chunmeng Xu, F. Haque, Chanyeop Park, L. Graber
Supercritical fluid (SCF), an intermediate state between gas and liquid, has been recently considered for being used as insulating media owing to properties that show exceptional dielectric strength, high heat transfer capability, and low viscosity. However, research on utilizing SCFs for power applications is still in its early stage, leaving literature and useful data on this topic very limited. This paper reviews and compares available literature related to the dielectric properties of SCFs, especially the electrical breakdown characteristics. Representative researches on the experimental demonstration of the discharge phenomenon in SCFs are summarized in this review. Important transport properties of SCFs, including viscosity, heat capacity, and thermal conductivity, are discussed. Furthermore, key parameters that define their dielectric properties, including conductivity and permittivity, are compared and summarized. Applications that require strong electric fields, efficient heat dissipation, and fast motion can benefit from using SCFs as a dielectric medium. The objective of this study is to provide a new perspective and useful recommendations on the selection of dielectric media for various practical purposes.
{"title":"A Review on Dielectric Properties of Supercritical Fluids","authors":"Jia Wei, A. Cruz, Chunmeng Xu, F. Haque, Chanyeop Park, L. Graber","doi":"10.1109/eic47619.2020.9158733","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158733","url":null,"abstract":"Supercritical fluid (SCF), an intermediate state between gas and liquid, has been recently considered for being used as insulating media owing to properties that show exceptional dielectric strength, high heat transfer capability, and low viscosity. However, research on utilizing SCFs for power applications is still in its early stage, leaving literature and useful data on this topic very limited. This paper reviews and compares available literature related to the dielectric properties of SCFs, especially the electrical breakdown characteristics. Representative researches on the experimental demonstration of the discharge phenomenon in SCFs are summarized in this review. Important transport properties of SCFs, including viscosity, heat capacity, and thermal conductivity, are discussed. Furthermore, key parameters that define their dielectric properties, including conductivity and permittivity, are compared and summarized. Applications that require strong electric fields, efficient heat dissipation, and fast motion can benefit from using SCFs as a dielectric medium. The objective of this study is to provide a new perspective and useful recommendations on the selection of dielectric media for various practical purposes.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128687750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158692
A. Khazanov, A. Gegenava, F. Dawson
Historically, groundwall insulation for high voltage rotating machine (HVRM) stator windings operate at higher electrical stresses for machines with a higher rated voltage. Thus, the insulation thickness is not proportional to the machine rated voltage. Both mechanical and electrical capabilities of insulation are taken in account to define groundwall insulation thickness based on long term practical experience. With the replacement of an older insulation system with a newer insulation system the aforementioned design concept for insulation wall thickness is preserved. While a newer system usually has increased electrical stresses, the consideration of lower electrical stresses for lower rated voltages usually stays unchanged. In some cases however the newer insulation system may allow for a different approach, but which should be carefully evaluated. The authors have observed that voltage endurance life expectancy for a thinner insulation for high voltage rotating machine stator windings made of a modern insulation based on mica paper and a thermosetting matrix provides the same or better voltage endurance life expectancy as a thicker insulation wall when voltage endurance tests are performed at the same electrical stress. Also mechanical stresses are lower in a thinner insulation if the insulation itself is not a part of the winding structural support. Conversely, for a thinner insulation wall, the impact of a single layer of taped insulation more or less is more significant than for a thicker insulation. This paper considers factors to be taken in to account to design reliable and efficient stator winding ground wall insulation for high voltage rotating machines with different rated voltages.
{"title":"Considerations for Maximum Operational Stresses in Electrical Insulation for High Voltage Machines Stator Windings for Different Rated Voltages","authors":"A. Khazanov, A. Gegenava, F. Dawson","doi":"10.1109/eic47619.2020.9158692","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158692","url":null,"abstract":"Historically, groundwall insulation for high voltage rotating machine (HVRM) stator windings operate at higher electrical stresses for machines with a higher rated voltage. Thus, the insulation thickness is not proportional to the machine rated voltage. Both mechanical and electrical capabilities of insulation are taken in account to define groundwall insulation thickness based on long term practical experience. With the replacement of an older insulation system with a newer insulation system the aforementioned design concept for insulation wall thickness is preserved. While a newer system usually has increased electrical stresses, the consideration of lower electrical stresses for lower rated voltages usually stays unchanged. In some cases however the newer insulation system may allow for a different approach, but which should be carefully evaluated. The authors have observed that voltage endurance life expectancy for a thinner insulation for high voltage rotating machine stator windings made of a modern insulation based on mica paper and a thermosetting matrix provides the same or better voltage endurance life expectancy as a thicker insulation wall when voltage endurance tests are performed at the same electrical stress. Also mechanical stresses are lower in a thinner insulation if the insulation itself is not a part of the winding structural support. Conversely, for a thinner insulation wall, the impact of a single layer of taped insulation more or less is more significant than for a thicker insulation. This paper considers factors to be taken in to account to design reliable and efficient stator winding ground wall insulation for high voltage rotating machines with different rated voltages.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129324914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158737
D. E. Moghadam, C. Herold, R. Zbinden
A question of great interest to the eDrive and automotive industries is whether resins affect the partial discharge behavior and lifetime of insulation systems. To answer this question, the role of resins on insulation system durability was investigated by testing system performance under various conditions. Twisted pairs (TPs) insulated with different materials were prepared according to appropriate standards and impregnated with resins. The partial discharge inception voltage (PDIV) (under AC and pulse voltage), capacitance and lifetime of samples with and without resin were then measured at room and high temperature. The results show that the main factors significantly affecting the PDIV of eDrive motor insulation systems are the insulation thickness of the copper wires and resin build. The findings further show that at high temperature, the PDIV and the lifetime of the TPs are also affected by the thermal behavior and chemistry of the resin.
{"title":"Effects of Resins on Partial Discharge Activity and Lifetime of Insulation Systems Used in eDrive Motors and Automotive Industries","authors":"D. E. Moghadam, C. Herold, R. Zbinden","doi":"10.1109/eic47619.2020.9158737","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158737","url":null,"abstract":"A question of great interest to the eDrive and automotive industries is whether resins affect the partial discharge behavior and lifetime of insulation systems. To answer this question, the role of resins on insulation system durability was investigated by testing system performance under various conditions. Twisted pairs (TPs) insulated with different materials were prepared according to appropriate standards and impregnated with resins. The partial discharge inception voltage (PDIV) (under AC and pulse voltage), capacitance and lifetime of samples with and without resin were then measured at room and high temperature. The results show that the main factors significantly affecting the PDIV of eDrive motor insulation systems are the insulation thickness of the copper wires and resin build. The findings further show that at high temperature, the PDIV and the lifetime of the TPs are also affected by the thermal behavior and chemistry of the resin.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123894893","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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