Pub Date : 2011-10-01DOI: 10.1109/CEIDP.2011.6232649
Y. Shcherbakov, L. Nekhamkin
The paper presents some results on spectroscopic studies of the filamentary streamer discharge in short air gap in stage of primary streamer propagation. Basically, we have found that the mid-resolved (with spectral resolution around 0.2-0.3 nm) nitrogen second positive system (SPS) spectra emitted from the primary streamer head changes essentially in form within some nanoseconds. Namely, main peak near the band head formed by the P-branches of Pi3-to-Pi3 transition turns almost into a widened twin-peak hump, relative intensities of each sub-peaks change in time resulting finally in a quite usual one-peak form; with inessential modification of short-wave part of the SPS-band as whole formed mainly by the R-branches. In attempt to give an appropriate realistic interpretation of this phenomenon we have analyzed different possible instrumental factors as well as mechanisms applied in streamer theory and molecular spectroscopy, such as: 1) dynamic breaking of the spin-axis coupling of the Pi3-states resulting in an appearance of Pi3(a)-to-Pi3(b)- and Pi3(b)-to-Pi3(b)-transitions additionally to a standard Pi3(a)-to-Pi3(a)-transition; 2) modeling of luminosity emitted from the actual high-gradient too narrow streamer head propagating with very high speed; 3) fast eventual heating of neutral gas within streamer head; 4) possible non-even illumination of the monochromator entrance slit due to very strong gradient of all physical parameters within streamer head and finally as well as actual sub-nanosecond temporal resolution of the measuring system; 5) Zeeman and Stark-effects. Stark-effect and instrumental peculiarities are supposed to be most adequate reasons for the phenomenon, which after development of relevant detailed theory might be applicable to determine/estimate electric field and its spatial gradient, respectively
{"title":"Transformation of nitrogen SPS spectra emitted from streamer discharge head within a sub-nanosecond — Nanosecond range","authors":"Y. Shcherbakov, L. Nekhamkin","doi":"10.1109/CEIDP.2011.6232649","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232649","url":null,"abstract":"The paper presents some results on spectroscopic studies of the filamentary streamer discharge in short air gap in stage of primary streamer propagation. Basically, we have found that the mid-resolved (with spectral resolution around 0.2-0.3 nm) nitrogen second positive system (SPS) spectra emitted from the primary streamer head changes essentially in form within some nanoseconds. Namely, main peak near the band head formed by the P-branches of Pi3-to-Pi3 transition turns almost into a widened twin-peak hump, relative intensities of each sub-peaks change in time resulting finally in a quite usual one-peak form; with inessential modification of short-wave part of the SPS-band as whole formed mainly by the R-branches. In attempt to give an appropriate realistic interpretation of this phenomenon we have analyzed different possible instrumental factors as well as mechanisms applied in streamer theory and molecular spectroscopy, such as: 1) dynamic breaking of the spin-axis coupling of the Pi3-states resulting in an appearance of Pi3(a)-to-Pi3(b)- and Pi3(b)-to-Pi3(b)-transitions additionally to a standard Pi3(a)-to-Pi3(a)-transition; 2) modeling of luminosity emitted from the actual high-gradient too narrow streamer head propagating with very high speed; 3) fast eventual heating of neutral gas within streamer head; 4) possible non-even illumination of the monochromator entrance slit due to very strong gradient of all physical parameters within streamer head and finally as well as actual sub-nanosecond temporal resolution of the measuring system; 5) Zeeman and Stark-effects. Stark-effect and instrumental peculiarities are supposed to be most adequate reasons for the phenomenon, which after development of relevant detailed theory might be applicable to determine/estimate electric field and its spatial gradient, respectively","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"95 1","pages":"271-274"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86018793","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232603
J. Crine
It is shown that under high fields, molecular straining becomes significant and that it affects the energy barrier equation for electrical aging of polymers. This implies that at high fields the time to go over the barrier varies not only with the stress (i.e. with the square of field) but also with the square of the stress. Examples are shown along with the corresponding calculated activation volume and the strained activation volume. The physical sense of the two activated volumes is discussed. The Kramers friction coefficient is also included in the life equation and the three main parameters affecting the energy barrier are calculated from various experiments with polyethylene and polypropylene. Discussion of dc and ac aging results are also made. The fact that the activation volume and the friction coefficient vary with the applied stress is illustrated and empirical approaches to determine them are suggested. Implications for other electrical properties are briefly discussed.
{"title":"Bonds breaking and molecular chains straining in the electrical aging of PE and PP","authors":"J. Crine","doi":"10.1109/CEIDP.2011.6232603","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232603","url":null,"abstract":"It is shown that under high fields, molecular straining becomes significant and that it affects the energy barrier equation for electrical aging of polymers. This implies that at high fields the time to go over the barrier varies not only with the stress (i.e. with the square of field) but also with the square of the stress. Examples are shown along with the corresponding calculated activation volume and the strained activation volume. The physical sense of the two activated volumes is discussed. The Kramers friction coefficient is also included in the life equation and the three main parameters affecting the energy barrier are calculated from various experiments with polyethylene and polypropylene. Discussion of dc and ac aging results are also made. The fact that the activation volume and the friction coefficient vary with the applied stress is illustrated and empirical approaches to determine them are suggested. Implications for other electrical properties are briefly discussed.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"116 1","pages":"89-92"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86085763","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232630
H. Hoshina, Y. Morisawa, S. Ishii, H. Sato, I. Noda, Y. Ozaki, C. Otani
Terahertz (THz) absorption spectra of poly(3-hydroxyalkanotes) (PHA) were measured by a terahertz time-domain spectrometer and Fourier transform far-infrared spectrometer. Clear differences were observed between the spectra of crystalline and amorphous PHA, indicating that the absorption peaks observed in the THz spectra originated in the higher-order conformation of PHA. Direction of the vibrational transition moments was obtained by the polarization spectra of stretched sample in which the crystal axis were aligned. THz spectra were also measured over a temperature range from 10 K to 465 K with a liquid helium cryostat and a heating cell. The temperature dependences of the spectra reveal frequency shifts and broadening of the absorption peaks with temperature, suggesting large anharmonicity of the vibrational potential.
{"title":"Terahertz spectroscopy of poly(3-hydroxyalkanoate)s","authors":"H. Hoshina, Y. Morisawa, S. Ishii, H. Sato, I. Noda, Y. Ozaki, C. Otani","doi":"10.1109/CEIDP.2011.6232630","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232630","url":null,"abstract":"Terahertz (THz) absorption spectra of poly(3-hydroxyalkanotes) (PHA) were measured by a terahertz time-domain spectrometer and Fourier transform far-infrared spectrometer. Clear differences were observed between the spectra of crystalline and amorphous PHA, indicating that the absorption peaks observed in the THz spectra originated in the higher-order conformation of PHA. Direction of the vibrational transition moments was obtained by the polarization spectra of stretched sample in which the crystal axis were aligned. THz spectra were also measured over a temperature range from 10 K to 465 K with a liquid helium cryostat and a heating cell. The temperature dependences of the spectra reveal frequency shifts and broadening of the absorption peaks with temperature, suggesting large anharmonicity of the vibrational potential.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"26 1","pages":"195-198"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86424934","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232697
Wei Wang, Yan Xue, Yangchun Cheng, Bing Zhou, Jianfeng Xu, Chengrong Li
To research the diagnosis method based ultra high frequency (UHF) signal and dissolved gases analysis (DGA) in oil of severity degree for oil/pressboard insulation surface discharge, a surface discharge simulation and test equipment and measurement system have been set up in laboratory, which were consisted of surface discharge model, test tank, UHF sensor, gas-phase chromatographic instrument and partial discharge detector. Surface discharge growth from inception to breakdown has been simulated, test voltage was raised step by step, ultra high frequency signal and dissolved gases in oil have been measured in the growth. The results show that severity degree of surface discharge can be divided tree stages: inception stage, growth stage and critical stage according to statistics spectrum of the ultra high frequency signal; ultra high frequency signal and dissolved gases in oil both can indicate the oil/pressboard surface discharge severity degree, however, dissolved gases analysis method was not as sensitive as ultra high frequency method; C2H2/total hydrocarbon generated by oil/pressboard surface discharge was more than 10%; Surface discharge was in critical stage when C2H2/total hydrocarbon value more than 50% and raised rapidly.
{"title":"Diagnosis of severity degree for oil/pressboard insulation surface discharge","authors":"Wei Wang, Yan Xue, Yangchun Cheng, Bing Zhou, Jianfeng Xu, Chengrong Li","doi":"10.1109/CEIDP.2011.6232697","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232697","url":null,"abstract":"To research the diagnosis method based ultra high frequency (UHF) signal and dissolved gases analysis (DGA) in oil of severity degree for oil/pressboard insulation surface discharge, a surface discharge simulation and test equipment and measurement system have been set up in laboratory, which were consisted of surface discharge model, test tank, UHF sensor, gas-phase chromatographic instrument and partial discharge detector. Surface discharge growth from inception to breakdown has been simulated, test voltage was raised step by step, ultra high frequency signal and dissolved gases in oil have been measured in the growth. The results show that severity degree of surface discharge can be divided tree stages: inception stage, growth stage and critical stage according to statistics spectrum of the ultra high frequency signal; ultra high frequency signal and dissolved gases in oil both can indicate the oil/pressboard surface discharge severity degree, however, dissolved gases analysis method was not as sensitive as ultra high frequency method; C2H2/total hydrocarbon generated by oil/pressboard surface discharge was more than 10%; Surface discharge was in critical stage when C2H2/total hydrocarbon value more than 50% and raised rapidly.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"5 1","pages":"472-475"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87545989","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232696
Bibo Geng, Chengrong Li, B. Qi, Le Yu, Jixin Gao
In order to compare the sensitivity between the UHF and ultrasonic methods for partial discharge detecting in GIS, a 252kV GIS experimental platform was established. Four typical defect models are taken into consideration, including metal particle stuck on the insulator surface; free metal particle on the insulator surface; ground electrode defect and poor contact of high voltage electrode. Through the PD inception voltage and the PRPD (phase resolved partial discharge) spectrogram of UHF and ultrasonic signals, the sensitivity and feature of UHF and ultrasonic methods could be compared. The results indicate that: 1) Compared to the ultrasonic method, the UHF method could detect all four defects mentioned above with high sensitivity. 2) The ultrasonic method could only detect some models with high sensitivity.
{"title":"The comparison of sensitivity between the UHF and ultrasonic methods for partial discharge detecting in GIS","authors":"Bibo Geng, Chengrong Li, B. Qi, Le Yu, Jixin Gao","doi":"10.1109/CEIDP.2011.6232696","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232696","url":null,"abstract":"In order to compare the sensitivity between the UHF and ultrasonic methods for partial discharge detecting in GIS, a 252kV GIS experimental platform was established. Four typical defect models are taken into consideration, including metal particle stuck on the insulator surface; free metal particle on the insulator surface; ground electrode defect and poor contact of high voltage electrode. Through the PD inception voltage and the PRPD (phase resolved partial discharge) spectrogram of UHF and ultrasonic signals, the sensitivity and feature of UHF and ultrasonic methods could be compared. The results indicate that: 1) Compared to the ultrasonic method, the UHF method could detect all four defects mentioned above with high sensitivity. 2) The ultrasonic method could only detect some models with high sensitivity.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"10 1","pages":"468-471"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87556167","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232610
Y. Watanabe, Y. Muramoto, N. Shimizu
TiO2 has photocatalysis. When UV light is irradiated, electron-hole pairs are generated in TiO2. The source of photocatalysis is oxidation and reduction reactions at the surface due to electrons and holes. Therefore, it is considered that the photocatalytic activities are closely related to electronic properties of the TiO2 under UV light irradiation. In this paper, we obtained Hall voltage properties in anatase TiO2 thin films under UV light irradiation. Furthermore, we successfully separated two current components due to electrons and holes using a new technique. We obtained the following results; 1. The measured values and polarity of the Hall voltage were not stable compared with those of n-type silicon. 2. The current component of electrons was almost the same with that of holes. From these results, it is suggested that the values of electron mobility and hole mobility are close.
{"title":"Electronic conduction properties of TiO2 thin films under UV light irradiation","authors":"Y. Watanabe, Y. Muramoto, N. Shimizu","doi":"10.1109/CEIDP.2011.6232610","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232610","url":null,"abstract":"TiO2 has photocatalysis. When UV light is irradiated, electron-hole pairs are generated in TiO2. The source of photocatalysis is oxidation and reduction reactions at the surface due to electrons and holes. Therefore, it is considered that the photocatalytic activities are closely related to electronic properties of the TiO2 under UV light irradiation. In this paper, we obtained Hall voltage properties in anatase TiO2 thin films under UV light irradiation. Furthermore, we successfully separated two current components due to electrons and holes using a new technique. We obtained the following results; 1. The measured values and polarity of the Hall voltage were not stable compared with those of n-type silicon. 2. The current component of electrons was almost the same with that of holes. From these results, it is suggested that the values of electron mobility and hole mobility are close.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"65 1","pages":"117-120"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87210522","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232627
A. Abdelmalik, J. Fothergill, S. Dodd
Natural ester fluids have been synthesized from crude palm kernel oil for consideration as an alternative to mineral oil based insulating fluid. Chemical modification of the oil enhanced the physico-chemical properties of the fluid. This paper presents the statistical analysis of the AC electrical breakdown strength of the synthesized esters in comparison with the crude palm kernel oil sample. The breakdown test was carried out in accordance with ASTM 1816 test method using a bespoke test cell designed for small sample volume. The estimated characteristic breakdown strength of the esters, defined as the 63.2% cumulative failure probability, is significantly higher than the BS148 mineral oil. The slopes, indicating the shape parameters, are similar. The results suggest that, at least in this regard, the synthesized esters may serve as an alternative to mineral oil as a transformer fluid.
{"title":"Electrical breakdown strength characteristics of palm kernel oil ester-based dielectric fluids","authors":"A. Abdelmalik, J. Fothergill, S. Dodd","doi":"10.1109/CEIDP.2011.6232627","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232627","url":null,"abstract":"Natural ester fluids have been synthesized from crude palm kernel oil for consideration as an alternative to mineral oil based insulating fluid. Chemical modification of the oil enhanced the physico-chemical properties of the fluid. This paper presents the statistical analysis of the AC electrical breakdown strength of the synthesized esters in comparison with the crude palm kernel oil sample. The breakdown test was carried out in accordance with ASTM 1816 test method using a bespoke test cell designed for small sample volume. The estimated characteristic breakdown strength of the esters, defined as the 63.2% cumulative failure probability, is significantly higher than the BS148 mineral oil. The slopes, indicating the shape parameters, are similar. The results suggest that, at least in this regard, the synthesized esters may serve as an alternative to mineral oil as a transformer fluid.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"38 1","pages":"183-186"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85324516","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232644
D. Robalino
Typically, dissipation factor (DF) or power factor (PF) test is carried out in the field following well known procedures. It is not necessary to emphasize the importance of dielectric test for power system operators. Accurate recording of insulation temperature values during the test is critical but not always feasible in the field. DF measured values are later normalized to a 20°C base for future comparison and trending. Nevertheless, as stated in several international publications, accuracy of temperature correction is still under investigation because temperature correction factors (TCF) from reference tables do not consider the percentage moisture concentration of the insulation system. The existing Temperature Correction Tables correspond to a variety of insulation materials and construction of different high voltage electrical equipment and components. Therefore, the application of state-of-the-art technologies to determine “specific” temperature correction factors for DF, is essential to provide reliable interpretation of results and proper equipment condition assessment. Frequency Domain Spectroscopy (FDS) in conjunction with DF Analysis are a powerful tool to determine the percentage moisture concentration in solid insulation capable to estimate Individual Temperature Compensation (ITC) of DF measured data of power transformers. Throughout this document, field experience is summarized when a three-winding transformer is removed from service and put to a series of testing procedures including DF, FDS and tip-up test on the high voltage bushings. Results of the analysis, experimental data and conclusions made based on the obtained results are presented herein.
{"title":"Accurate temperature correction of dissipation factor data for oil-impregnated paper insulation bushings: Field experience","authors":"D. Robalino","doi":"10.1109/CEIDP.2011.6232644","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232644","url":null,"abstract":"Typically, dissipation factor (DF) or power factor (PF) test is carried out in the field following well known procedures. It is not necessary to emphasize the importance of dielectric test for power system operators. Accurate recording of insulation temperature values during the test is critical but not always feasible in the field. DF measured values are later normalized to a 20°C base for future comparison and trending. Nevertheless, as stated in several international publications, accuracy of temperature correction is still under investigation because temperature correction factors (TCF) from reference tables do not consider the percentage moisture concentration of the insulation system. The existing Temperature Correction Tables correspond to a variety of insulation materials and construction of different high voltage electrical equipment and components. Therefore, the application of state-of-the-art technologies to determine “specific” temperature correction factors for DF, is essential to provide reliable interpretation of results and proper equipment condition assessment. Frequency Domain Spectroscopy (FDS) in conjunction with DF Analysis are a powerful tool to determine the percentage moisture concentration in solid insulation capable to estimate Individual Temperature Compensation (ITC) of DF measured data of power transformers. Throughout this document, field experience is summarized when a three-winding transformer is removed from service and put to a series of testing procedures including DF, FDS and tip-up test on the high voltage bushings. Results of the analysis, experimental data and conclusions made based on the obtained results are presented herein.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"43 1","pages":"251-254"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87338016","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232593
T. Koltunowicz, A. Cavallini, D. Djairam, G. Montanari, J. Smit
The use of Voltage Source Converters (VSCs) in HVDC transmission and, more generally, in flexible AC transmission systems (FACTS), raises concerns over the endurance of turn/turn insulation of grid/converter interface transformers. In this paper, tests performed on oil-impregnated paper specimens are discussed. The results indicate clearly that shorter rise times and higher repetition frequencies have a strong impact on both partial discharge inception voltage and breakdown voltage. These results suggest that deeper investigation might be important to understand the long term behavior of these insulation systems.
{"title":"The influence of square voltage waveforms on transformer insulation break down voltage","authors":"T. Koltunowicz, A. Cavallini, D. Djairam, G. Montanari, J. Smit","doi":"10.1109/CEIDP.2011.6232593","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232593","url":null,"abstract":"The use of Voltage Source Converters (VSCs) in HVDC transmission and, more generally, in flexible AC transmission systems (FACTS), raises concerns over the endurance of turn/turn insulation of grid/converter interface transformers. In this paper, tests performed on oil-impregnated paper specimens are discussed. The results indicate clearly that shorter rise times and higher repetition frequencies have a strong impact on both partial discharge inception voltage and breakdown voltage. These results suggest that deeper investigation might be important to understand the long term behavior of these insulation systems.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"2 1","pages":"48-51"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83891798","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 : 2011-10-01DOI: 10.1109/CEIDP.2011.6232690
D. Adhikari, D. Hepburn, B. Stewart
Partial Discharge (PD) results from faults in power insulation systems and exacerbates failure. It is known that the presence of voids in solid and liquid insulation give rise to PD. Factors which control the PD activity include pressure and type of gas present. When PD occurs in insulation, pressure is created and gaseous products changed due to the energy input. A series of experiments is being carried out on artificial voids, created from layered sections of polymer. One set of samples has a void inside the polymer with no access to the outer atmosphere; a second set of samples is created with a vent connecting the void to the outer atmosphere. Both sample sets are stressed at the same electrical conditions for same period of time. Investigation of the physical and chemical differences and PD patterns recorded follows.
{"title":"Comparison of PD characteristics and degradation in PET insulation with vented and unvented voids","authors":"D. Adhikari, D. Hepburn, B. Stewart","doi":"10.1109/CEIDP.2011.6232690","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232690","url":null,"abstract":"Partial Discharge (PD) results from faults in power insulation systems and exacerbates failure. It is known that the presence of voids in solid and liquid insulation give rise to PD. Factors which control the PD activity include pressure and type of gas present. When PD occurs in insulation, pressure is created and gaseous products changed due to the energy input. A series of experiments is being carried out on artificial voids, created from layered sections of polymer. One set of samples has a void inside the polymer with no access to the outer atmosphere; a second set of samples is created with a vent connecting the void to the outer atmosphere. Both sample sets are stressed at the same electrical conditions for same period of time. Investigation of the physical and chemical differences and PD patterns recorded follows.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"99 1","pages":"444-447"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82599411","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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