Space charge existed in polymer subjected DC high electrical stress has attracted more and more attention over the world. Various methods of inhibiting space charge generation and accumulation had been attempted in order to reduce insulation deterioration. In the present paper, the polyethylene/montmorillonite nanocomposites are prepared by melting intercalation process. The distribution of space charges in the nano-composite is investigated by means of pulse electric acoustic (PEA) method under different conditions. The effects of maleic anhydride grafted polyethylene (PEMA) on space charge characteristics of the composites are discussed. The test results indicate that the heterogeneous space charges in the nanocomposite near the cathode gradually decrease with PEMA content increasing. When PEMA content is 20%, the heterogeneous space charges near the cathode almost disappear at all in the nanocomposite. In short-circuiting process, the residual space charges in the nanocomposite with compatilizer obviously decrease comparing with origin LDPE. It is suggested that PEMA as a compatilizer can improve the interaction combination between LDPE and O-MMT, consequently interfacial traps reduce.
{"title":"Study on space charge behaviour in polyethylene doped with nano-montmorillonite","authors":"Junguo Gao, X. Zhou, Liang Sun, Taiming Zhang, Xiaohong Zhang","doi":"10.1109/ICSD.2013.6619900","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619900","url":null,"abstract":"Space charge existed in polymer subjected DC high electrical stress has attracted more and more attention over the world. Various methods of inhibiting space charge generation and accumulation had been attempted in order to reduce insulation deterioration. In the present paper, the polyethylene/montmorillonite nanocomposites are prepared by melting intercalation process. The distribution of space charges in the nano-composite is investigated by means of pulse electric acoustic (PEA) method under different conditions. The effects of maleic anhydride grafted polyethylene (PEMA) on space charge characteristics of the composites are discussed. The test results indicate that the heterogeneous space charges in the nanocomposite near the cathode gradually decrease with PEMA content increasing. When PEMA content is 20%, the heterogeneous space charges near the cathode almost disappear at all in the nanocomposite. In short-circuiting process, the residual space charges in the nanocomposite with compatilizer obviously decrease comparing with origin LDPE. It is suggested that PEMA as a compatilizer can improve the interaction combination between LDPE and O-MMT, consequently interfacial traps reduce.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121894745","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619899
M. Hoang, L. Boudou, S. Le Roy, G. Teyssèdre
Thermo-stimulated depolarization current (TSDC) measurements have been performed on poly(ethylene naphthalene 2,6-dicarboxylate) (PEN), an aromatic polyester. The aim is to develop the understanding of trapping mechanisms at play in this material, and particularly to understand the effect of temperature. Experimental results of TSDC are interpreted with the help of space charge measurements using the pulsed electroacoustic method (PEA) on PEN samples. For TSDC measurements, samples were polarized at temperatures of 130°C and 170°C. In both cases, the sub-glass transition and the glass transition relaxations are observed. However, in the case of a polarization temperature of 170°C, one more TSDC peak, so-called ρ-peak is observed at temperatures above the glass transition. From space charge results, it is shown that the ρ-peak has not a dipolar origin; it has been associated to charge detrapping in the material.
{"title":"Electrical characterization of PEN films using TSDC and PEA measurements","authors":"M. Hoang, L. Boudou, S. Le Roy, G. Teyssèdre","doi":"10.1109/ICSD.2013.6619899","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619899","url":null,"abstract":"Thermo-stimulated depolarization current (TSDC) measurements have been performed on poly(ethylene naphthalene 2,6-dicarboxylate) (PEN), an aromatic polyester. The aim is to develop the understanding of trapping mechanisms at play in this material, and particularly to understand the effect of temperature. Experimental results of TSDC are interpreted with the help of space charge measurements using the pulsed electroacoustic method (PEA) on PEN samples. For TSDC measurements, samples were polarized at temperatures of 130°C and 170°C. In both cases, the sub-glass transition and the glass transition relaxations are observed. However, in the case of a polarization temperature of 170°C, one more TSDC peak, so-called ρ-peak is observed at temperatures above the glass transition. From space charge results, it is shown that the ρ-peak has not a dipolar origin; it has been associated to charge detrapping in the material.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117042596","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619696
Yuanxiang Zhou, F. Jin, Q. Sun, Y. Sha, Meng Huang
The valve side winding of the converter transformers withstood several types of voltage. This paper investigated the effects of voltage component on the surface flashover characteristics of oil-paper insulation under combined AC-DC voltage in different ratio. The whole flashover process of surface flashover of oil-paper insulation under combined AC-DC voltage was studied by using two types of electrodes. The experimental conclusion was shown that the flashover voltage increased with the DC ratio in the combined AC-DC voltage component. Flashover voltage decreased significantly when the radial electric field increases in the electric field component. Furthermore, electric field distributions versus combined AC-DC voltage in different ratio were calculated by Finite Element Analysis (FEA). Due to the different distribution characteristics of DC electric field and AC electric field, when the DC ratio was higher, the surface flashover location tended to pressboard surface. Conversely, when the AC ratio was higher, it tended to the oil gap between the electrodes. Moreover, based on high-speed camera, it was used to capture emitted light produced by surface flashover, record flashover initiation and propagation process in small oil gap between the electrodes.
{"title":"Surface flashover characteristics of oil-paper insulation under combined AC-DC voltage","authors":"Yuanxiang Zhou, F. Jin, Q. Sun, Y. Sha, Meng Huang","doi":"10.1109/ICSD.2013.6619696","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619696","url":null,"abstract":"The valve side winding of the converter transformers withstood several types of voltage. This paper investigated the effects of voltage component on the surface flashover characteristics of oil-paper insulation under combined AC-DC voltage in different ratio. The whole flashover process of surface flashover of oil-paper insulation under combined AC-DC voltage was studied by using two types of electrodes. The experimental conclusion was shown that the flashover voltage increased with the DC ratio in the combined AC-DC voltage component. Flashover voltage decreased significantly when the radial electric field increases in the electric field component. Furthermore, electric field distributions versus combined AC-DC voltage in different ratio were calculated by Finite Element Analysis (FEA). Due to the different distribution characteristics of DC electric field and AC electric field, when the DC ratio was higher, the surface flashover location tended to pressboard surface. Conversely, when the AC ratio was higher, it tended to the oil gap between the electrodes. Moreover, based on high-speed camera, it was used to capture emitted light produced by surface flashover, record flashover initiation and propagation process in small oil gap between the electrodes.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129761382","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619784
C. Freitag, I. Mladenovic, C. Weindl
In modern power utilities attention is especially directed to the condition determination of the network's electrical equipment, with the purpose of supporting the condition oriented asset management and maintenance strategies. In medium voltage (MV) networks, cables require the biggest investment capital. In order to point out the most suitable diagnostic parameters and their limits, a long lasting accelerated and artificial ageing experiment on MV paper insulated lead covered (PILC) cables was performed. The in this way determined dependencies of the diagnostic parameters on voltage, temperature and condition of the cables, as well as characteristic values and regarded failure probability play an immense role in the determination of cables' condition in field measurements. Still, the diagnostic criterion (e.g. in case of dissipation losses comparison of: absolute value, hysteresis, dependency on testing voltage) could significantly influence the final diagnostic statement. In addition, the recorded values have to be evaluated regarding the composition of the cable line. This problematic will be shown in the article and discussed on several exemplar field measurements.
{"title":"An interpretation approach for in field measured dissipation factor values of MV cable lines","authors":"C. Freitag, I. Mladenovic, C. Weindl","doi":"10.1109/ICSD.2013.6619784","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619784","url":null,"abstract":"In modern power utilities attention is especially directed to the condition determination of the network's electrical equipment, with the purpose of supporting the condition oriented asset management and maintenance strategies. In medium voltage (MV) networks, cables require the biggest investment capital. In order to point out the most suitable diagnostic parameters and their limits, a long lasting accelerated and artificial ageing experiment on MV paper insulated lead covered (PILC) cables was performed. The in this way determined dependencies of the diagnostic parameters on voltage, temperature and condition of the cables, as well as characteristic values and regarded failure probability play an immense role in the determination of cables' condition in field measurements. Still, the diagnostic criterion (e.g. in case of dissipation losses comparison of: absolute value, hysteresis, dependency on testing voltage) could significantly influence the final diagnostic statement. In addition, the recorded values have to be evaluated regarding the composition of the cable line. This problematic will be shown in the article and discussed on several exemplar field measurements.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128711244","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619875
J. Rubio-Serrano, J. Posada, I. Bua, J. A. García-Souto
A partial discharge (PD) is a phenomenon related to the degradation of the insulation systems in HV equipment like power transformers. PD is present in the entire life of the HV equipment but its presence is not an indicative of the existence of a critical defect in the insulation. However, if a set of PD are located in a small region or the repetition rate is high in a small temporal window, then there is a high probability of an imminent failure of the equipment. The detection of the acoustic emission (AE) generated by PD is a non-intrusive technique which can be used for the detection and location of PD in order to perform online condition assessment of insulation systems in power transformers. Although the multiple advantages of the acoustic detection, it has several difficulties to overcome like strong attenuation, signal distortion or accurate arrival time determination. In the last years, new digital signal processing (DSP) techniques has been studied to improve the signal to noise ratio (SNR) of the signals and the detection of the beginning of the detected signals. The objective of this work is the analysis of these DSP techniques in order to improve the diagnosis of power transformers by means of the detection of the AE.
{"title":"Comparison of processing techniques for optimizing the diagnosis of solid insulation based on acoustic emissions from partial discharges","authors":"J. Rubio-Serrano, J. Posada, I. Bua, J. A. García-Souto","doi":"10.1109/ICSD.2013.6619875","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619875","url":null,"abstract":"A partial discharge (PD) is a phenomenon related to the degradation of the insulation systems in HV equipment like power transformers. PD is present in the entire life of the HV equipment but its presence is not an indicative of the existence of a critical defect in the insulation. However, if a set of PD are located in a small region or the repetition rate is high in a small temporal window, then there is a high probability of an imminent failure of the equipment. The detection of the acoustic emission (AE) generated by PD is a non-intrusive technique which can be used for the detection and location of PD in order to perform online condition assessment of insulation systems in power transformers. Although the multiple advantages of the acoustic detection, it has several difficulties to overcome like strong attenuation, signal distortion or accurate arrival time determination. In the last years, new digital signal processing (DSP) techniques has been studied to improve the signal to noise ratio (SNR) of the signals and the detection of the beginning of the detected signals. The objective of this work is the analysis of these DSP techniques in order to improve the diagnosis of power transformers by means of the detection of the AE.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"4 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130593998","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619862
N. Zhao, Shengtao Li, Xia Wang, Guochang Li
Space charge characteristics of double-layer dielectric, which consists of low density polyethylene (LDPE) and nano-titania filled LDPE (named TiO2-LDPE), have been tested by pulsed electro acoustic (PEA) method under different high voltage direct current (HVDC) electric fields. The TiO2-LDPE material is fabricated by doping nano-TiO2 into free additive LDPE with different weight proportions of 0.5 parts per hundred parts of resin (phr), 2 phr and 5 phr, respectively. Furthermore, the effects of LDPE/TiO2-LDPE interface on space charge behavior are discussed when the LDPE layer is both on the side of anode and cathode by reversing the double-layer dielectric. The results indicate that positive carriers accumulate at the interface of samples whose LDPE layer is located on the side of anode when electric field increases to certain value. However, negative carrier accumulation happens to the interface of samples whose LDPE layer is on the side of cathode. The higher the electric field, the larger the amount of interface charges accumulated. But there is no obvious difference of charge amount among systems with different nano-TiO2 concentrations. The formation of the interface space charge is considered as the result of conductivity difference between LDPE and TiO2-LDPE as well as influence of surface morphology. Moreover, it can be seen that the charge peak at cathode broadens when the LDPE layer is on the side of anode. At the same time, a small positive charge peak appears near cathode and the charge peak at anode broadens when the LDPE layer is on the side of cathode. The case is the most obvious under 5 phr. It is believed to be caused by induced charges of the interface charges. The induced charges have opposite polarity and distribute near the electrodes. The results provide an effective space charge controlling method, which makes it possible to locate space charge in the position required. It will be helpful for further optimization of HVDC cable.
{"title":"Effects of LDPE/nanofilled LDPE interface on space charge formation","authors":"N. Zhao, Shengtao Li, Xia Wang, Guochang Li","doi":"10.1109/ICSD.2013.6619862","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619862","url":null,"abstract":"Space charge characteristics of double-layer dielectric, which consists of low density polyethylene (LDPE) and nano-titania filled LDPE (named TiO2-LDPE), have been tested by pulsed electro acoustic (PEA) method under different high voltage direct current (HVDC) electric fields. The TiO2-LDPE material is fabricated by doping nano-TiO2 into free additive LDPE with different weight proportions of 0.5 parts per hundred parts of resin (phr), 2 phr and 5 phr, respectively. Furthermore, the effects of LDPE/TiO2-LDPE interface on space charge behavior are discussed when the LDPE layer is both on the side of anode and cathode by reversing the double-layer dielectric. The results indicate that positive carriers accumulate at the interface of samples whose LDPE layer is located on the side of anode when electric field increases to certain value. However, negative carrier accumulation happens to the interface of samples whose LDPE layer is on the side of cathode. The higher the electric field, the larger the amount of interface charges accumulated. But there is no obvious difference of charge amount among systems with different nano-TiO2 concentrations. The formation of the interface space charge is considered as the result of conductivity difference between LDPE and TiO2-LDPE as well as influence of surface morphology. Moreover, it can be seen that the charge peak at cathode broadens when the LDPE layer is on the side of anode. At the same time, a small positive charge peak appears near cathode and the charge peak at anode broadens when the LDPE layer is on the side of cathode. The case is the most obvious under 5 phr. It is believed to be caused by induced charges of the interface charges. The induced charges have opposite polarity and distribute near the electrodes. The results provide an effective space charge controlling method, which makes it possible to locate space charge in the position required. It will be helpful for further optimization of HVDC cable.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123932564","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619758
L. Zavattoni, O. Lesaint, O. Gallot-Lavallée
Surface resistance measurements on insulating solids are usually performed by measuring the current induced when an electric field tangential to the surface is applied. The measured current results from the addition of currents flowing along the surface, and also partly in the volume. In this paper, surface current measurements on an alumina-filled epoxy resin are performed under varying conditions of temperature (40-60°C), relative humidity (0-80 %), gas nature (SF6, N2, air), pressure (0.1-0.8 MPa). In dry conditions, measured currents do not depend on the gas nature and pressure. In air, when the relative humidity (RH) is varied, a large influence is measured, and the recorded variation of surface currents includes two phases: a rapid one attributed to the immediate change of surface resistance, followed by a much slower variation attributed to the progressive impregnation of the material by water. Numerical simulation shows the dominant influence of surface properties on measured currents, and evidences the existence of a surface layer with a higher conductivity compared to the material volume, even in dry conditions.
{"title":"Surface resistance measurements on epoxy composites: Influence of surrounding gas, pressure, temperature, and analysis of the origin of measured currents","authors":"L. Zavattoni, O. Lesaint, O. Gallot-Lavallée","doi":"10.1109/ICSD.2013.6619758","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619758","url":null,"abstract":"Surface resistance measurements on insulating solids are usually performed by measuring the current induced when an electric field tangential to the surface is applied. The measured current results from the addition of currents flowing along the surface, and also partly in the volume. In this paper, surface current measurements on an alumina-filled epoxy resin are performed under varying conditions of temperature (40-60°C), relative humidity (0-80 %), gas nature (SF6, N2, air), pressure (0.1-0.8 MPa). In dry conditions, measured currents do not depend on the gas nature and pressure. In air, when the relative humidity (RH) is varied, a large influence is measured, and the recorded variation of surface currents includes two phases: a rapid one attributed to the immediate change of surface resistance, followed by a much slower variation attributed to the progressive impregnation of the material by water. Numerical simulation shows the dominant influence of surface properties on measured currents, and evidences the existence of a surface layer with a higher conductivity compared to the material volume, even in dry conditions.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124153255","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619765
M. Praeger, A. Vaughan, S. Swingler
In this study a simple solvent blending technique is used to produce silica/polystyrene nanocomposites. Dielectric spectroscopy is then used to measure both the real and imaginary permittivity of the samples. The nanosilica/polystyrene system is characterized over a range of different filler loadings, and additionally, as a function of temperature. To supplement this, absorbed water is used as a dielectric probe to explore molecular relaxation processes at the nanoparticle interfaces.
{"title":"A dielectric spectroscopy study of the polystyrene/nanosilica model system","authors":"M. Praeger, A. Vaughan, S. Swingler","doi":"10.1109/ICSD.2013.6619765","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619765","url":null,"abstract":"In this study a simple solvent blending technique is used to produce silica/polystyrene nanocomposites. Dielectric spectroscopy is then used to measure both the real and imaginary permittivity of the samples. The nanosilica/polystyrene system is characterized over a range of different filler loadings, and additionally, as a function of temperature. To supplement this, absorbed water is used as a dielectric probe to explore molecular relaxation processes at the nanoparticle interfaces.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121402261","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619738
A. Huzayyin, S. Boggs, R. Ramprasad
Computational quantum mechanics, within the frame work of density functional theory (DFT) was used to determine the depths of impurity states created by common chemical impurities in polyethylene. Depths of traps/hopping sites were between 0.1 eV and 2.4 eV and were classified into shallow traps/hopping sites, deep traps, and deeper traps. Such depths suggest that chemical impurities can play major roles in trapping and hopping processes, can explain the observed activation energy of conduction, and shape the barriers to charge injection. Thus, chemical impurities could dominate high field conduction in polyethylene. The type of impurity bonds and their lengths are correlated with the depth of impurities they create. Such correlation is linear. A procedure to determine depth of states created by an impurity, without using DFT is presented.
{"title":"Depths of chemical impurity states in Polyethylene; The big picture from first principles","authors":"A. Huzayyin, S. Boggs, R. Ramprasad","doi":"10.1109/ICSD.2013.6619738","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619738","url":null,"abstract":"Computational quantum mechanics, within the frame work of density functional theory (DFT) was used to determine the depths of impurity states created by common chemical impurities in polyethylene. Depths of traps/hopping sites were between 0.1 eV and 2.4 eV and were classified into shallow traps/hopping sites, deep traps, and deeper traps. Such depths suggest that chemical impurities can play major roles in trapping and hopping processes, can explain the observed activation energy of conduction, and shape the barriers to charge injection. Thus, chemical impurities could dominate high field conduction in polyethylene. The type of impurity bonds and their lengths are correlated with the depth of impurities they create. Such correlation is linear. A procedure to determine depth of states created by an impurity, without using DFT is presented.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114070549","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 : 2013-10-08DOI: 10.1109/ICSD.2013.6619806
Xin Luo, H. Niu, Juzhuo Wu
Suppressing narrow-band interference is one of the key techniques of partial discharge (PD) on-line monitoring. Based on the characteristics analysis of FFT power spectrum of PD signals with and without the narrow-band interference, the partial peaks and partial energy ratio is defined. Thus, a method of suppressing narrow-band interference using partial energy ratio pretreatment is proposed, and the steps are also detailed. Besides, the magnitude of partial energy ratio is fuzzified and the adaptive fuzzy C-mean threshold algorithm is proposed to extract the threshold of partial energy ratio. The denoising results show that the proposed method could pick narrow-band interference from the real PD signal.
{"title":"A modified method of suppressing narrow-band interference using FFT power spectrum","authors":"Xin Luo, H. Niu, Juzhuo Wu","doi":"10.1109/ICSD.2013.6619806","DOIUrl":"https://doi.org/10.1109/ICSD.2013.6619806","url":null,"abstract":"Suppressing narrow-band interference is one of the key techniques of partial discharge (PD) on-line monitoring. Based on the characteristics analysis of FFT power spectrum of PD signals with and without the narrow-band interference, the partial peaks and partial energy ratio is defined. Thus, a method of suppressing narrow-band interference using partial energy ratio pretreatment is proposed, and the steps are also detailed. Besides, the magnitude of partial energy ratio is fuzzified and the adaptive fuzzy C-mean threshold algorithm is proposed to extract the threshold of partial energy ratio. The denoising results show that the proposed method could pick narrow-band interference from the real PD signal.","PeriodicalId":437475,"journal":{"name":"2013 IEEE International Conference on Solid Dielectrics (ICSD)","volume":"17 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114018845","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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