Effects of electrode baking at a comparatively low temperature in vacuum have been examined. The temperature of the electrode is controlled well below the melting point of organic insulators, if installed. Currents accompanied by the microdischarges and the conditioning process during breakdown test are observed. It is shown that low temperature baking effectively suppresses the microdischarge, and that baking of the anode is more effective than baking of the cathode. It is also shown that baking reduces the number of voltage applications which are necessary for the spark conditioning. >
{"title":"Effect of low-temperature electrode baking on breakdown in vacuum","authors":"O. Yamamoto, T. Hara, M. Shimada, M. Hayashi","doi":"10.1109/14.231540","DOIUrl":"https://doi.org/10.1109/14.231540","url":null,"abstract":"Effects of electrode baking at a comparatively low temperature in vacuum have been examined. The temperature of the electrode is controlled well below the melting point of organic insulators, if installed. Currents accompanied by the microdischarges and the conditioning process during breakdown test are observed. It is shown that low temperature baking effectively suppresses the microdischarge, and that baking of the anode is more effective than baking of the cathode. It is also shown that baking reduces the number of voltage applications which are necessary for the spark conditioning. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72947388","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}
K. Frohlich, H. Karner, D. Konig, M. Lindmayer, K. Moller, W. Rieder
The main activities in the field of vacuum interrupters carried out by the authors' research groups at technical universities in Germany and Austria are discussed. A wide field of dielectric programs has been treated. Work concerning arc modes and motion is reported. Questions of current zero at line frequency and high frequency, as well as chopping characteristics, have been investigated. In many investigations, the influence of contact material has been of great importance. >
{"title":"Fundamental research on vacuum interrupters at technical universities in Germany and Austria","authors":"K. Frohlich, H. Karner, D. Konig, M. Lindmayer, K. Moller, W. Rieder","doi":"10.1109/14.231542","DOIUrl":"https://doi.org/10.1109/14.231542","url":null,"abstract":"The main activities in the field of vacuum interrupters carried out by the authors' research groups at technical universities in Germany and Austria are discussed. A wide field of dielectric programs has been treated. Work concerning arc modes and motion is reported. Questions of current zero at line frequency and high frequency, as well as chopping characteristics, have been investigated. In many investigations, the influence of contact material has been of great importance. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80573523","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}
Breakdown voltages of three-electrode arrangements have been determined. The shield electrode shows a significant influence on the breakdown behavior of the electrode arrangement at the investigated gap distances between 10 and 20 mm and at shield diameters of 100 to 120 mm. Confirming former investigations, the breakdown voltages increase according to the material in the order: copper, stainless steel, aluminium. The amplitudes of the AC prebreakdown conditioning voltages are of great importance if the measured breakdown voltages are compared. The electrical strength of three-electrode arrangements can be increased by 30% if field-optimized electrodes are used. The breakdown of a three-electrode gap is normally not included by a charging or discharging of the shield electrode. >
{"title":"The influence of a cylindrical shield electrode on the dielectric strength of large vacuum gaps","authors":"B. Kahl, H. Karner","doi":"10.1109/14.231528","DOIUrl":"https://doi.org/10.1109/14.231528","url":null,"abstract":"Breakdown voltages of three-electrode arrangements have been determined. The shield electrode shows a significant influence on the breakdown behavior of the electrode arrangement at the investigated gap distances between 10 and 20 mm and at shield diameters of 100 to 120 mm. Confirming former investigations, the breakdown voltages increase according to the material in the order: copper, stainless steel, aluminium. The amplitudes of the AC prebreakdown conditioning voltages are of great importance if the measured breakdown voltages are compared. The electrical strength of three-electrode arrangements can be increased by 30% if field-optimized electrodes are used. The breakdown of a three-electrode gap is normally not included by a charging or discharging of the shield electrode. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91328792","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}
S. Anders, B. Juttner, M. Lindmayer, C. Rusteberg, H. Pursch, F. Unger-Weber
The delay time of voltage breakdown has been analyzed as a function of the time interval to preceding interruption of high currents. With intervals >1 ms the behavior of the gap corresponded to cold electrodes. For this case, in a separate experiment, the dependence of the delay time on various parameters has been studied. At constant voltage a steep increased with the gap distance was found. This leads to the conclusion that field emission rather than a clump process is responsible for late breakdowns. >
{"title":"Vacuum breakdown with microsecond delay time (interrupters)","authors":"S. Anders, B. Juttner, M. Lindmayer, C. Rusteberg, H. Pursch, F. Unger-Weber","doi":"10.1109/14.231526","DOIUrl":"https://doi.org/10.1109/14.231526","url":null,"abstract":"The delay time of voltage breakdown has been analyzed as a function of the time interval to preceding interruption of high currents. With intervals >1 ms the behavior of the gap corresponded to cold electrodes. For this case, in a separate experiment, the dependence of the delay time on various parameters has been studied. At constant voltage a steep increased with the gap distance was found. This leads to the conclusion that field emission rather than a clump process is responsible for late breakdowns. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80176858","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}
The frequency of breakdown phenomena in a HV system under ultrahigh vacuum, can be increased by orders of magnitude by the presence of radiation, either in the form of electromagnetic waves (laser and UV light, synchrotron light, X-rays, gamma rays) or charged particles and ions. Both types of radiation are abundant in high-energy e/sup +/e/sup -/ colliders, and studies of the effect of a particular radiation source in this difficult environment are subject to many limitations. Thus, the principal strategy is to reduce the radiation flux incident on critical devices by absorbing the electromagnetic radiation or by trapping the charged particles. However, in the case of the 'pretzel' separation project for CERN's large electron positron (LEP) collider, this strategy failed. As a result many experiments have been carried out in order to achieve a better understanding of radiation-triggered breakdown phenomena. Observations made in some other e/sup +/e/sup -/ colliders are also reported. >
{"title":"Radiation-triggered breakdown phenomena in high-energy e/sup +/e/sup -/ colliders","authors":"W. Kalbreier, B. Goddard","doi":"10.1109/14.231524","DOIUrl":"https://doi.org/10.1109/14.231524","url":null,"abstract":"The frequency of breakdown phenomena in a HV system under ultrahigh vacuum, can be increased by orders of magnitude by the presence of radiation, either in the form of electromagnetic waves (laser and UV light, synchrotron light, X-rays, gamma rays) or charged particles and ions. Both types of radiation are abundant in high-energy e/sup +/e/sup -/ colliders, and studies of the effect of a particular radiation source in this difficult environment are subject to many limitations. Thus, the principal strategy is to reduce the radiation flux incident on critical devices by absorbing the electromagnetic radiation or by trapping the charged particles. However, in the case of the 'pretzel' separation project for CERN's large electron positron (LEP) collider, this strategy failed. As a result many experiments have been carried out in order to achieve a better understanding of radiation-triggered breakdown phenomena. Observations made in some other e/sup +/e/sup -/ colliders are also reported. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89821172","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}
M. Irmisch, A. Ulbricht, V. Zwecker, R. Badent, A. Hinderer, J. Olbrisch, M. Jaarah
The breakdown of He between plane electrodes was investigated under conditions similar to those of the operation of superconducting magnets at room temperature and 4 K. It was found that the breakdown voltage in the Paschen minimum was higher than expected at room temperature, which was explained by the presence of impurity. An additional effect observed, especially at low pressures, is that the measured pressure in the vacuum vessel does not seem to agree with the pressure of the electrode gap. Furthermore a helium leak of 1 Pa 1/s was introduced between the electrodes. No measurable influence of this leak was found within the measuring accuracy at low temperatures. >
{"title":"Breakdown characteristics of He gas at cryogenic temperature and low pressure","authors":"M. Irmisch, A. Ulbricht, V. Zwecker, R. Badent, A. Hinderer, J. Olbrisch, M. Jaarah","doi":"10.1109/14.231533","DOIUrl":"https://doi.org/10.1109/14.231533","url":null,"abstract":"The breakdown of He between plane electrodes was investigated under conditions similar to those of the operation of superconducting magnets at room temperature and 4 K. It was found that the breakdown voltage in the Paschen minimum was higher than expected at room temperature, which was explained by the presence of impurity. An additional effect observed, especially at low pressures, is that the measured pressure in the vacuum vessel does not seem to agree with the pressure of the electrode gap. Furthermore a helium leak of 1 Pa 1/s was introduced between the electrodes. No measurable influence of this leak was found within the measuring accuracy at low temperatures. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80029023","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}
Systematic investigations of the relationship between the surface finish, the polishing medium, and surface flashover properties of high purity polycrystalline alumina ceramics are reported. Samples polished with SiC abrasives displayed a linear behavior, with the breakdown strength increasing with decreasing surface roughness. The breakdown properties of the diamond polished samples were influenced significantly by the polishing sequence adopted; samples polished from coarser to finer finish exhibited erratic surface breakdown properties, whereas the breakdown properties of samples polished from finer to coarser finish varied linearly with respect to the particle size of the abrasive used in the final polishing. These results are discussed in terms of surface and subsurface defects that are formed during diamond polishing. The breakdown properties of the samples in relation to the abrasive type are also analyzed. >
{"title":"Dependence of the surface flashover properties of alumina on polishing abrasive parameters","authors":"T. Asokan, T. S. Surdashan","doi":"10.1109/14.231536","DOIUrl":"https://doi.org/10.1109/14.231536","url":null,"abstract":"Systematic investigations of the relationship between the surface finish, the polishing medium, and surface flashover properties of high purity polycrystalline alumina ceramics are reported. Samples polished with SiC abrasives displayed a linear behavior, with the breakdown strength increasing with decreasing surface roughness. The breakdown properties of the diamond polished samples were influenced significantly by the polishing sequence adopted; samples polished from coarser to finer finish exhibited erratic surface breakdown properties, whereas the breakdown properties of samples polished from finer to coarser finish varied linearly with respect to the particle size of the abrasive used in the final polishing. These results are discussed in terms of surface and subsurface defects that are formed during diamond polishing. The breakdown properties of the samples in relation to the abrasive type are also analyzed. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88325012","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}
Surface flashover properties in relation to test procedures were investigated, using single-cycle steady step, multiple-cycle steady-step, multiple-shot, and hill-valley tests. In general, the test procedures were found to influence significantly the surface flashover properties of large-bandgap insulators such as polycrystalline alumina and signal-crystal quartz in vacuum. The steady-step tests increased the degree of conditioning to a higher level during the second day. However, the samples subjected to these tests displayed a higher degree of deconditioning during the second and third day. A simultaneous increase of conditioning and decrease of deconditioning was observed for the multiple-shot and hill-valley tests. The surface flashover performances of 6- mu m-finish alumina specimens for different test procedures are also compared and discussed. The behavior of the insulators under a given test procedure is explained on the basis of surface electronic defects and adsorbed gaseous atoms or molecules. >
{"title":"Optimization of test procedure to improve insulator performance under high electric stress","authors":"T. Asokan, T. S. Surdashan","doi":"10.1109/14.231537","DOIUrl":"https://doi.org/10.1109/14.231537","url":null,"abstract":"Surface flashover properties in relation to test procedures were investigated, using single-cycle steady step, multiple-cycle steady-step, multiple-shot, and hill-valley tests. In general, the test procedures were found to influence significantly the surface flashover properties of large-bandgap insulators such as polycrystalline alumina and signal-crystal quartz in vacuum. The steady-step tests increased the degree of conditioning to a higher level during the second day. However, the samples subjected to these tests displayed a higher degree of deconditioning during the second and third day. A simultaneous increase of conditioning and decrease of deconditioning was observed for the multiple-shot and hill-valley tests. The surface flashover performances of 6- mu m-finish alumina specimens for different test procedures are also compared and discussed. The behavior of the insulators under a given test procedure is explained on the basis of surface electronic defects and adsorbed gaseous atoms or molecules. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86180032","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}
Results of recent investigations dealing with the fundamentals of two new methods to check the vacuum inside the chamber, using only electrical parameters, are presented. With increasing pressure, the prebreakdown current changes in such a way that not only do the power frequency emission current patterns change, but also high-frequency current pulses, with a frequency range of approximately 30 to 300 kHz, appear superimposed on the emission current. It is reported under which conditions these pulse currents appear, how they can be detected, and how they correlate with the pressure. When the current is interrupted at a frequency range of approximately 10 to 90 kHz, the current switching capability and the reignition voltages change significantly with increasing pressure inside the vacuum chamber. The vacuum chamber loses its high-frequency current switching capability when the internal pressure is higher than approximately 10/sup -2/ to 10/sup -1/ Pa. The breakdown voltage and reignition voltages do not appreciably decrease even when the pressure rises to approximately 1 Pa. >
{"title":"Electrical methods for verifying internal pressure of vacuum interrupters after long-time service","authors":"F. Frontzek, D. Konig, R. Heinemeyer","doi":"10.1109/14.231546","DOIUrl":"https://doi.org/10.1109/14.231546","url":null,"abstract":"Results of recent investigations dealing with the fundamentals of two new methods to check the vacuum inside the chamber, using only electrical parameters, are presented. With increasing pressure, the prebreakdown current changes in such a way that not only do the power frequency emission current patterns change, but also high-frequency current pulses, with a frequency range of approximately 30 to 300 kHz, appear superimposed on the emission current. It is reported under which conditions these pulse currents appear, how they can be detected, and how they correlate with the pressure. When the current is interrupted at a frequency range of approximately 10 to 90 kHz, the current switching capability and the reignition voltages change significantly with increasing pressure inside the vacuum chamber. The vacuum chamber loses its high-frequency current switching capability when the internal pressure is higher than approximately 10/sup -2/ to 10/sup -1/ Pa. The breakdown voltage and reignition voltages do not appreciably decrease even when the pressure rises to approximately 1 Pa. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83760696","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}
The properties of the prebreakdown response of silicon-vacuum systems under HV excitation are presented. The most frequent case of system breakdown by surface flashover is treated. The particular properties of the system response in the high-field pulsed regime demonstrate the essential differences between the silicon-vacuum and solid-insulator-vacuum systems. The main ideas of a new physical model of surface flashover in silicon-vacuum systems are presented. The properties of the surface flashover response are discussed in terms of the proposed model. A concept called system surface flashover sensitivity is introduced to provide a better understanding of the surface flashover physical process in silicon-vacuum systems. >
{"title":"Surface flashover in silicon-vacuum systems","authors":"G. Gradinaru, V. Madangarli, T. Sudarshan","doi":"10.1109/14.231538","DOIUrl":"https://doi.org/10.1109/14.231538","url":null,"abstract":"The properties of the prebreakdown response of silicon-vacuum systems under HV excitation are presented. The most frequent case of system breakdown by surface flashover is treated. The particular properties of the system response in the high-field pulsed regime demonstrate the essential differences between the silicon-vacuum and solid-insulator-vacuum systems. The main ideas of a new physical model of surface flashover in silicon-vacuum systems are presented. The properties of the surface flashover response are discussed in terms of the proposed model. A concept called system surface flashover sensitivity is introduced to provide a better understanding of the surface flashover physical process in silicon-vacuum systems. >","PeriodicalId":13105,"journal":{"name":"IEEE Transactions on Electrical Insulation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83504765","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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