Pub Date : 2003-10-19DOI: 10.1109/CEIDP.2003.1254800
M. Pompili, R. Campi
Recently has been submitted for publication the revision of IEC 60296, which concerns specification for unused mineral oils to be employed in switchgear and transformers. For the transformers, the IEC 60296 Standard, in comparison with the past Edition, introduces oils with a reduced viscosity having obviously also a decreased flash point. At the same time a new Standard (Project IEC 60076) is now under development, actually in circulation as Committee Draft: "Guide for design and application of liquid-immersed power transformers using high-temperature insulation materials". This Guide, among others, include also mineral oils (called HTM-240 and HTM-205) having a much higher flash points, up to 240/spl deg/C, accompanied with acceptable increases in their viscosities. It seems to be a very interesting point to investigate how change the electrical properties of these new mineral oils having increased and reduced viscosities.
{"title":"A study of electrical characteristics of mineral transformer oils with reduced and increased viscosity","authors":"M. Pompili, R. Campi","doi":"10.1109/CEIDP.2003.1254800","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254800","url":null,"abstract":"Recently has been submitted for publication the revision of IEC 60296, which concerns specification for unused mineral oils to be employed in switchgear and transformers. For the transformers, the IEC 60296 Standard, in comparison with the past Edition, introduces oils with a reduced viscosity having obviously also a decreased flash point. At the same time a new Standard (Project IEC 60076) is now under development, actually in circulation as Committee Draft: \"Guide for design and application of liquid-immersed power transformers using high-temperature insulation materials\". This Guide, among others, include also mineral oils (called HTM-240 and HTM-205) having a much higher flash points, up to 240/spl deg/C, accompanied with acceptable increases in their viscosities. It seems to be a very interesting point to investigate how change the electrical properties of these new mineral oils having increased and reduced viscosities.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116954068","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254797
Boong-joo Lee, G. Park, D. You, D. Lee
For thin resistor films with low TCR (temperature coefficient of resistance) and high resistivity, we have prepared the thin films by cosputtering method with pure Ni and Cr targets and studied the effect of the process parameters on the electrical properties. In sputtering process, DC/RF power and pressure are varied as controllable parameters. We have investigated the microstructure and measured the electrical properties. When the Ni/Cr ratios of the deposited thin films were 0.8 /spl sim/ 1.5, the resistivity was 100 /spl sim/ 120 /spl mu/ /spl Omega//spl middot/cm. Below a Ni/Cr ratio of 1.5 (above 40[wt%] of Cr), the TCR became negative. The TCR of the thin films decreased from -30 ppm//spl deg/C to -75 ppm//spl deg/C with increasing Cr content. It is suggested that the composition ratio and electrical properties of thin films can be controlled by variation of sputter process parameters.
{"title":"Composition control and electrical properties of Ni-Cr thin films prepared by co-sputtering method","authors":"Boong-joo Lee, G. Park, D. You, D. Lee","doi":"10.1109/CEIDP.2003.1254797","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254797","url":null,"abstract":"For thin resistor films with low TCR (temperature coefficient of resistance) and high resistivity, we have prepared the thin films by cosputtering method with pure Ni and Cr targets and studied the effect of the process parameters on the electrical properties. In sputtering process, DC/RF power and pressure are varied as controllable parameters. We have investigated the microstructure and measured the electrical properties. When the Ni/Cr ratios of the deposited thin films were 0.8 /spl sim/ 1.5, the resistivity was 100 /spl sim/ 120 /spl mu/ /spl Omega//spl middot/cm. Below a Ni/Cr ratio of 1.5 (above 40[wt%] of Cr), the TCR became negative. The TCR of the thin films decreased from -30 ppm//spl deg/C to -75 ppm//spl deg/C with increasing Cr content. It is suggested that the composition ratio and electrical properties of thin films can be controlled by variation of sputter process parameters.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117220526","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254839
K. I. Wong, P. Lewin, S. Dodd
Electroluminescence excitation mechanisms have been investigated in a low-density polyethylene film under an applied ac electrical field. The principle of phase resolved electroluminescence measurement using a charge coupled device camera is outlined in this paper. Experimental results from several tested samples have shown that the samples can be divided into two different groups according to the emission spatial distribution: (1) homogeneous and (2) localised spots superimposed on a homogeneous emission. At the same applied voltage, the homogeneous and localised spots EL spectral resolutions have maximum light emitted from the near infra red and visible regions respectively. This suggests that space charge on a localised surface area might induce a divergent field and transfer the charge into deep traps at an appropriate voltage amplitude.
{"title":"Electroluminescence phenomena of low density polyethylene film under applied ac voltage","authors":"K. I. Wong, P. Lewin, S. Dodd","doi":"10.1109/CEIDP.2003.1254839","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254839","url":null,"abstract":"Electroluminescence excitation mechanisms have been investigated in a low-density polyethylene film under an applied ac electrical field. The principle of phase resolved electroluminescence measurement using a charge coupled device camera is outlined in this paper. Experimental results from several tested samples have shown that the samples can be divided into two different groups according to the emission spatial distribution: (1) homogeneous and (2) localised spots superimposed on a homogeneous emission. At the same applied voltage, the homogeneous and localised spots EL spectral resolutions have maximum light emitted from the near infra red and visible regions respectively. This suggests that space charge on a localised surface area might induce a divergent field and transfer the charge into deep traps at an appropriate voltage amplitude.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127172924","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254904
R. Candela, C. Petrarca, P. Romano
As shown in recent papers, Partial Discharge activity has a fundamental role in the premature failure of electrical insulation of machine stator windings fed by PWM inverters. The existence of Partial Discharges can be easily explained if the presence of micro voids inside a composite insulation is considered to be unavoidable. Since such micro cavities are filled with a gas whose permittivity is generally several times lower than the permittivity of the surrounding dielectric, the electric field in such occlusions can be much higher than the local expected average stress. On the basis of a numerical study carried out by using a multi conductor transmission line model for the evaluation of the potential distribution inside the machine and a PD simulation model for the evaluation of the possible ensuing PD activity, in this paper, a new experimental approach to evaluate the effect of PD generated by inverter distorted voltages is proposed. PD measurements under 50 Hz -10 kHz quasi-square and sine wave voltage waveform are performed by means of an Hv capacitive bridge measurement system in order to reject external disturbances, like voltage overshoots, and they are acquired by ultra-wide band (UWB) acquisition system.
{"title":"Effect of high frequency conducted disturbances on the interturn insulation of an inverter-fed induction motor","authors":"R. Candela, C. Petrarca, P. Romano","doi":"10.1109/CEIDP.2003.1254904","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254904","url":null,"abstract":"As shown in recent papers, Partial Discharge activity has a fundamental role in the premature failure of electrical insulation of machine stator windings fed by PWM inverters. The existence of Partial Discharges can be easily explained if the presence of micro voids inside a composite insulation is considered to be unavoidable. Since such micro cavities are filled with a gas whose permittivity is generally several times lower than the permittivity of the surrounding dielectric, the electric field in such occlusions can be much higher than the local expected average stress. On the basis of a numerical study carried out by using a multi conductor transmission line model for the evaluation of the potential distribution inside the machine and a PD simulation model for the evaluation of the possible ensuing PD activity, in this paper, a new experimental approach to evaluate the effect of PD generated by inverter distorted voltages is proposed. PD measurements under 50 Hz -10 kHz quasi-square and sine wave voltage waveform are performed by means of an Hv capacitive bridge measurement system in order to reject external disturbances, like voltage overshoots, and they are acquired by ultra-wide band (UWB) acquisition system.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125361280","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254845
B. Buerschaper, O. Kleboth-Lugova, T. Leibfried
The operational reliability of power transformers depends primarily on the oil-transformerboard condition. It's well known, that the presence of moisture has significant influence on ageing of transformerboard and also on the dielectric strength of transformer oil. At constant temperature a moisture equilibrium between oil and transformerboard exists. The change of load conditions causes a change of temperature and as a result a migration of moisture between oil and transformerboard. These interactions are very important for the breakdown phenomena in oil-cellulose insulation. The disturbance of moisture equilibrium results in a significant reduction of the electrical strength of the oil, especially if the transformerboard has a water content more than 2.5%. This value is normally in an ageing transformer. The experimental investigations of the electrical strength of transformer oil during moisture nonequilibrium are presented. The transition conditions are simulated in an indirectly heated test setup, which represents the insulation system of a power transformer. This model has the same oil-transformerboard ratio (volume and surface area) as a real 200 MVA transformer. The parameters, having the main influence of the breakdown-voltage during the non-equilibrium state, are discussed.
{"title":"The electrical strength of transformer oil in a transformerboard-oil system during moisture non-equilibrium","authors":"B. Buerschaper, O. Kleboth-Lugova, T. Leibfried","doi":"10.1109/CEIDP.2003.1254845","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254845","url":null,"abstract":"The operational reliability of power transformers depends primarily on the oil-transformerboard condition. It's well known, that the presence of moisture has significant influence on ageing of transformerboard and also on the dielectric strength of transformer oil. At constant temperature a moisture equilibrium between oil and transformerboard exists. The change of load conditions causes a change of temperature and as a result a migration of moisture between oil and transformerboard. These interactions are very important for the breakdown phenomena in oil-cellulose insulation. The disturbance of moisture equilibrium results in a significant reduction of the electrical strength of the oil, especially if the transformerboard has a water content more than 2.5%. This value is normally in an ageing transformer. The experimental investigations of the electrical strength of transformer oil during moisture nonequilibrium are presented. The transition conditions are simulated in an indirectly heated test setup, which represents the insulation system of a power transformer. This model has the same oil-transformerboard ratio (volume and surface area) as a real 200 MVA transformer. The parameters, having the main influence of the breakdown-voltage during the non-equilibrium state, are discussed.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125825765","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254832
M. Fu, G. Chen
Space charge accumulation in XLPE power cable insulation under dc electric stress at room temperature and gradient temperature across the insulation was experimentally studied. It has been found that space charge is of a constant accumulation rate at room temperature and quite stable as soon as it is generated. In contrast, elevated temperature has not only reduced the charge density but also accelerated space charge accumulation and decay speed.
{"title":"Space charge measurement in XLPE cable with temperature gradient through the insulation","authors":"M. Fu, G. Chen","doi":"10.1109/CEIDP.2003.1254832","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254832","url":null,"abstract":"Space charge accumulation in XLPE power cable insulation under dc electric stress at room temperature and gradient temperature across the insulation was experimentally studied. It has been found that space charge is of a constant accumulation rate at room temperature and quite stable as soon as it is generated. In contrast, elevated temperature has not only reduced the charge density but also accelerated space charge accumulation and decay speed.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125856139","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254883
E. Soundarajan, E. Jackson, A. King, R. Stmdararajan
Thermoplastic elastomer (TPE) is a third generation polymeric material expected to meet most of the requirements of the high voltage outdoor insulation, at least for the distribution class applications, especially at light contamination environments. As a thermoplastic, it has benefits such as better speed, efficiency, and economy of processing over silicone rubber or any other thermoset polymers. Additionally, it is 100% recyclable and reusable and hence environmentally friendly. Being new, there are no published results available on the performance of TPE insulators under contaminated conditions. This paper reports the performance of 28 kV distribution class dead-end TPE insulator in comparison with same kV silicone rubber (SiR) insulator under two different salt fog conditions (4000 and 16000 /spl mu/S/cm) for 1000h. Both materials showed comparable performance in general.
{"title":"Performance of novel high voltage outdoor thermoplastic elastomeric insulators","authors":"E. Soundarajan, E. Jackson, A. King, R. Stmdararajan","doi":"10.1109/CEIDP.2003.1254883","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254883","url":null,"abstract":"Thermoplastic elastomer (TPE) is a third generation polymeric material expected to meet most of the requirements of the high voltage outdoor insulation, at least for the distribution class applications, especially at light contamination environments. As a thermoplastic, it has benefits such as better speed, efficiency, and economy of processing over silicone rubber or any other thermoset polymers. Additionally, it is 100% recyclable and reusable and hence environmentally friendly. Being new, there are no published results available on the performance of TPE insulators under contaminated conditions. This paper reports the performance of 28 kV distribution class dead-end TPE insulator in comparison with same kV silicone rubber (SiR) insulator under two different salt fog conditions (4000 and 16000 /spl mu/S/cm) for 1000h. Both materials showed comparable performance in general.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127355151","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254865
R. Kuppuswamy
Partial discharge detection sensitivity of three types of UHF partial discharge (PD) couplers, reportedly used in the literature, has been studied in comparison using experimentally simulated discharges and those discharges observed during PD acceptance testing of transformers. UHF PD measurements were performed by a digital instrument developed for the purpose. An interesting observation has been that UHF PD inception and detection sensitivity is linked to the appearance of PD pulse current impulses of negative polarity. The occurrence frequencies for PD and common noise sources do not appear to change with the type of the PD coupler used, although individual sensitivities vary. In the last part of the paper typical UHF PD patterns recorded using different couplers during PD acceptance testing of transformer is presented.
{"title":"On the UHF partial discharge measurement in transformers","authors":"R. Kuppuswamy","doi":"10.1109/CEIDP.2003.1254865","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254865","url":null,"abstract":"Partial discharge detection sensitivity of three types of UHF partial discharge (PD) couplers, reportedly used in the literature, has been studied in comparison using experimentally simulated discharges and those discharges observed during PD acceptance testing of transformers. UHF PD measurements were performed by a digital instrument developed for the purpose. An interesting observation has been that UHF PD inception and detection sensitivity is linked to the appearance of PD pulse current impulses of negative polarity. The occurrence frequencies for PD and common noise sources do not appear to change with the type of the PD coupler used, although individual sensitivities vary. In the last part of the paper typical UHF PD patterns recorded using different couplers during PD acceptance testing of transformer is presented.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124852056","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254936
R. Patsch, D. Benzerouk
The analysis of partial discharges is a common tool for the diagnosis of electric equipment, whereby in most cases only the phase angles at which the discharges occur and the pulse heights are registered. If the voltage is applied to only one end of the stator winding and the opposite is left on free potential, the impulse height distributions may be different in dependence on what side is energized. The detailed analysis revealed that characteristically different pulse shapes may occur. The paper will deal with experimental results and discuss in how far the different pulse shapes of the output signal of the coupling impedance can be used to identify different defects located in different regions of the winding.
{"title":"Analysis of partial discharges in stator windings","authors":"R. Patsch, D. Benzerouk","doi":"10.1109/CEIDP.2003.1254936","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254936","url":null,"abstract":"The analysis of partial discharges is a common tool for the diagnosis of electric equipment, whereby in most cases only the phase angles at which the discharges occur and the pulse heights are registered. If the voltage is applied to only one end of the stator winding and the opposite is left on free potential, the impulse height distributions may be different in dependence on what side is energized. The detailed analysis revealed that characteristically different pulse shapes may occur. The paper will deal with experimental results and discuss in how far the different pulse shapes of the output signal of the coupling impedance can be used to identify different defects located in different regions of the winding.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125235397","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 : 2003-10-19DOI: 10.1109/CEIDP.2003.1254933
D. James, I. Sauers, A. Ellis, M. Pace, D. Deschenes
The pressure inside an enclosed void in a solid dielectric is generally determined by calculation based on equating the measured partial discharge (PD) onset voltage and the breakdown voltage from the Paschen curve for a particular gas. Here it is assumed that the gas is known or that physical properties remain approximately constant. In the present experiment, two different large voids were placed in epoxy adjacent to the ground electrode containing a small pump out port. This arrangement allowed for direct measurement and setting of the pressure for different gases filling the void. PD onset and extinction voltages were determined as a function of pressure over the range from 13.3 Pa (0.1 torr) to 101 kPa (760 torr) for nitrogen and SF/sub 6/ at room temperature. The onset voltages generally followed the Paschen curve dependence on pressure but were higher in voltage at pressures around the minimum, while the extinction voltage followed the Paschen curve more closely in both pressure dependence and voltage. Agreement with the Paschen curve is better at the higher pressures. One possible explanation is the dominant role that real surfaces play at lower pressures.
固体介质中封闭空隙内的压力通常是通过计算某一特定气体的局部放电(PD)起始电压与Paschen曲线的击穿电压相等来确定的。这里假定气体是已知的，或者物理性质大致保持不变。在本实验中，在环氧树脂中放置两个不同的大空隙，邻近含有小泵出端口的接地电极。这种布置允许直接测量和设置填充空隙的不同气体的压力。在室温下，氮气和SF/sub / 6的PD发生和熄灭电压是压强在13.3 Pa (0.1 torr)到101 kPa (760 torr)范围内的函数。起始电压与压力的关系基本符合Paschen曲线，但在最小压力附近电压较高，而熄灭电压与压力和电压的关系更接近Paschen曲线。在较高的压力下，与Paschen曲线的一致性较好。一种可能的解释是，在较低的压力下，真实的表面起着主导作用。
{"title":"Effect of gas pressure on partial discharge in voids in epoxy","authors":"D. James, I. Sauers, A. Ellis, M. Pace, D. Deschenes","doi":"10.1109/CEIDP.2003.1254933","DOIUrl":"https://doi.org/10.1109/CEIDP.2003.1254933","url":null,"abstract":"The pressure inside an enclosed void in a solid dielectric is generally determined by calculation based on equating the measured partial discharge (PD) onset voltage and the breakdown voltage from the Paschen curve for a particular gas. Here it is assumed that the gas is known or that physical properties remain approximately constant. In the present experiment, two different large voids were placed in epoxy adjacent to the ground electrode containing a small pump out port. This arrangement allowed for direct measurement and setting of the pressure for different gases filling the void. PD onset and extinction voltages were determined as a function of pressure over the range from 13.3 Pa (0.1 torr) to 101 kPa (760 torr) for nitrogen and SF/sub 6/ at room temperature. The onset voltages generally followed the Paschen curve dependence on pressure but were higher in voltage at pressures around the minimum, while the extinction voltage followed the Paschen curve more closely in both pressure dependence and voltage. Agreement with the Paschen curve is better at the higher pressures. One possible explanation is the dominant role that real surfaces play at lower pressures.","PeriodicalId":306575,"journal":{"name":"2003 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122092807","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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