Pub Date : 2004-05-18DOI: 10.1109/DEIV.2004.1422672
R. Hollinger, M. Galonska, P. Spadtke
To fill up the GSI heavy ion synchrotron (US) to its space charge limit with uranium ions, a new vacuum arc ion source (VARIS), based on the MEVVA IV ion source has been developed and implemented into operation. The ion source has proven its capability in several long period beam times at the high current injector at GSI. With the new ion source it was possible to exceed the space charge limit of 15 mA U4+ ions at the entrance of the linear accelerator (UN1LAC)for the very first time. The reliability as well as the noise behaviour has been improved to such a degree, that this ion source can be used for injection info an accelerator without objection. In this article we present the improvements of the ion Source with the most important operational data. The emission current density of the new ion source has been increased from 60 mA/cm2 for the common used GSI-MEVVA to 170 mA/cm2. This results in a full beam ion current of 156 mA at 35 kV with a fraction of four fold charged uranium ions of 67%. The analysed U4+ ion beam after dc post acceleration amounts to 25 mA at 131 kV which is 1.7 times higher than the requested ion beam current at the entrance of the RFQ. The reduced power density of the vacuum arc results in a higher efficiency and longer life time. Solenoids which are creating magnetic fields to enhance the charge state of the ions are no more placed inside the vacuum system. This ion source design results in a higher availability after ion source replacement at the injector, and longer life time.
为了用铀离子填补GSI重离子同步加速器(US)的空间电荷极限，在MEVVA IV离子源的基础上研制了一种新型真空电弧离子源(VARIS)并投入运行。该离子源在GSI的大电流注入器中进行了多次长周期束流试验，证明了其性能。使用新的离子源，首次有可能在直线加速器(UN1LAC)入口处超过15 mA U4+离子的空间电荷限制。可靠性和噪声性能都得到了很大的改善，这种离子源可以毫无异议地用于加速器的注入。在本文中，我们用最重要的操作数据介绍了离子源的改进。新离子源的发射电流密度从常用的GSI-MEVVA的60 mA/cm2提高到170 mA/cm2。这就产生了35kv下156 mA的全束离子电流，其中铀离子的四倍电荷率为67%。经直流后加速后的U4+离子束在131 kV下达到25 mA，比RFQ入口要求的离子束电流高1.7倍。降低了真空电弧的功率密度，提高了效率，延长了寿命。产生磁场以增强离子电荷状态的螺线管不再放置在真空系统内。这种离子源设计可以在注入器更换离子源后获得更高的可用性，并延长使用寿命。
{"title":"Development of a vacuum arc ion source for injection of high current uranium ion beam into the unilac at GSI","authors":"R. Hollinger, M. Galonska, P. Spadtke","doi":"10.1109/DEIV.2004.1422672","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422672","url":null,"abstract":"To fill up the GSI heavy ion synchrotron (US) to its space charge limit with uranium ions, a new vacuum arc ion source (VARIS), based on the MEVVA IV ion source has been developed and implemented into operation. The ion source has proven its capability in several long period beam times at the high current injector at GSI. With the new ion source it was possible to exceed the space charge limit of 15 mA U4+ ions at the entrance of the linear accelerator (UN1LAC)for the very first time. The reliability as well as the noise behaviour has been improved to such a degree, that this ion source can be used for injection info an accelerator without objection. In this article we present the improvements of the ion Source with the most important operational data. The emission current density of the new ion source has been increased from 60 mA/cm2 for the common used GSI-MEVVA to 170 mA/cm2. This results in a full beam ion current of 156 mA at 35 kV with a fraction of four fold charged uranium ions of 67%. The analysed U4+ ion beam after dc post acceleration amounts to 25 mA at 131 kV which is 1.7 times higher than the requested ion beam current at the entrance of the RFQ. The reduced power density of the vacuum arc results in a higher efficiency and longer life time. Solenoids which are creating magnetic fields to enhance the charge state of the ions are no more placed inside the vacuum system. This ion source design results in a higher availability after ion source replacement at the injector, and longer life time.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"176 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115538490","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 : 2004-04-12DOI: 10.1109/DEIV.2004.1418658
A. Anders, E. Oks, G. Yushkov, I. Brown
A vacuum arc ion source was modified allowing us to collect ions from arc plasma streaming through an anode mesh. The mesh had a geometric transmittance of 60%, which was taken into account as a correction factor. The ion current from twenty-two cathode materials was measured at an arc current of 100 A. The ion current normalized by the arc current was found to depend on the cathode material, with values in the range from 5% to 11%. The normalized ion current is generally greater for light elements than for heavy elements. The ion erosion rates were determined from values of ion current and ion charge states, which were previously measured in the same experimental system. The ion erosion rates range from 12-94 μg/C.
{"title":"Measurement of total ion flux in vacuum are discharges","authors":"A. Anders, E. Oks, G. Yushkov, I. Brown","doi":"10.1109/DEIV.2004.1418658","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418658","url":null,"abstract":"A vacuum arc ion source was modified allowing us to collect ions from arc plasma streaming through an anode mesh. The mesh had a geometric transmittance of 60%, which was taken into account as a correction factor. The ion current from twenty-two cathode materials was measured at an arc current of 100 A. The ion current normalized by the arc current was found to depend on the cathode material, with values in the range from 5% to 11%. The normalized ion current is generally greater for light elements than for heavy elements. The ion erosion rates were determined from values of ion current and ion charge states, which were previously measured in the same experimental system. The ion erosion rates range from 12-94 μg/C.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121254727","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422693
U. Schumann, M. Budde, M. Kurrat
With a normal vacuum switch, shield electrodes are built into the system to control the electric field distribution. The shield electrodes thus represent an additional capacity, which is in parallel to the contact electrodes. The prediction of the high-voltage strength of such electrode arrangements in vacuum is complex. Effects of a wide range of parameters like electrode material_ surface finish: surface area, conditioning state of the surface and the geometry of the electrode arrangement exist. It is well known that the electrode's area influences the dielectric strength in vacuum. With increasing area the dielectric strength decreases, in the opposite direction the capacity of the electrode arrangement rises. This work shows that shields in a vacuum tube which represent a parallel capacity, do not alter the breakdown behaviour during lightning impulse voltage of the contact system. Since the gap distance of the shields lies clearly over that of the contact system, a reduction of the breakdown voltage is not to be expected from the increasing total surface by the ¿area effect¿. The empirical relation between the breakdown voltage and the area of the electrodes surface can also be described as a capacity influence. But the increasing capacity is not causal for the phenomenon. For this purpose. coplanar electrodes are stressed and conditioned with lightning impulse voltage (1.2/50μs). The test vessel is enabled to pick up more than one pair of electrodes. That makes possible to vary the total capacitance by a second or even third parallel connected pair of electrodes. The results of the measurements are discussed and compared to the area effect.
{"title":"Influence of shield capacity on the breakdown voltade of vacuum tubes","authors":"U. Schumann, M. Budde, M. Kurrat","doi":"10.1109/DEIV.2004.1422693","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422693","url":null,"abstract":"With a normal vacuum switch, shield electrodes are built into the system to control the electric field distribution. The shield electrodes thus represent an additional capacity, which is in parallel to the contact electrodes. The prediction of the high-voltage strength of such electrode arrangements in vacuum is complex. Effects of a wide range of parameters like electrode material_ surface finish: surface area, conditioning state of the surface and the geometry of the electrode arrangement exist. It is well known that the electrode's area influences the dielectric strength in vacuum. With increasing area the dielectric strength decreases, in the opposite direction the capacity of the electrode arrangement rises. This work shows that shields in a vacuum tube which represent a parallel capacity, do not alter the breakdown behaviour during lightning impulse voltage of the contact system. Since the gap distance of the shields lies clearly over that of the contact system, a reduction of the breakdown voltage is not to be expected from the increasing total surface by the ¿area effect¿. The empirical relation between the breakdown voltage and the area of the electrodes surface can also be described as a capacity influence. But the increasing capacity is not causal for the phenomenon. For this purpose. coplanar electrodes are stressed and conditioned with lightning impulse voltage (1.2/50μs). The test vessel is enabled to pick up more than one pair of electrodes. That makes possible to vary the total capacitance by a second or even third parallel connected pair of electrodes. The results of the measurements are discussed and compared to the area effect.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127276988","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422608
B. Miao, Yan Zhang, Guoxun Liu
This paper briefly reviews the Cu-Cr materials which are widely adopted for contacts in medium-voltage, high current vacuum circuit breakers (VCB). It is shown that microstructure is a strategic link between the processing and properties of the contact materials, and why the quality and performance of Cn-Cr alloy contact materials are superior to that of CuCr p/m contact materials.
{"title":"Current status and developing trends of Cu-Cr contact materials for VCB","authors":"B. Miao, Yan Zhang, Guoxun Liu","doi":"10.1109/DEIV.2004.1422608","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422608","url":null,"abstract":"This paper briefly reviews the Cu-Cr materials which are widely adopted for contacts in medium-voltage, high current vacuum circuit breakers (VCB). It is shown that microstructure is a strategic link between the processing and properties of the contact materials, and why the quality and performance of Cn-Cr alloy contact materials are superior to that of CuCr p/m contact materials.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115552952","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422675
T. Yanagidaira, W. Kotake, H. Miura, K. Tsuruta
Soft x-ray emission from a short vacuum gap, operated with a repetitive low-current discharge was investigated. Electrons are accelerated by an electric field in a cathode sheath that is formed after arc extinction, and soft x-rays were emitted in the period between arc extinction and subsequent breakdown. The schlieren photographs and Langmuir probe diagnostics showed that the micro plasma of diameter less than 1 mm is formed during arc phase, and the ion sheath extended with velocity of 104/m/s , which agreed with calculation. The existence time of the dense plasma was 10 - 20 ns.
{"title":"Temporal evolution of micro-plasma in a repetitive vacuum arc soft x-ray source","authors":"T. Yanagidaira, W. Kotake, H. Miura, K. Tsuruta","doi":"10.1109/DEIV.2004.1422675","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422675","url":null,"abstract":"Soft x-ray emission from a short vacuum gap, operated with a repetitive low-current discharge was investigated. Electrons are accelerated by an electric field in a cathode sheath that is formed after arc extinction, and soft x-rays were emitted in the period between arc extinction and subsequent breakdown. The schlieren photographs and Langmuir probe diagnostics showed that the micro plasma of diameter less than 1 mm is formed during arc phase, and the ion sheath extended with velocity of 104/m/s , which agreed with calculation. The existence time of the dense plasma was 10 - 20 ns.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116046082","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422619
Zou Ji-yan, Ding Fu-hua, Duan Xiong-ying
A novel reactive power compensator is developed for 10kV distribution system to improve power quality. It is composed of a synchronous vacuum circuit breaker (SVCB) and an intelligent power factor controller (IPFC). Electrical transients for switching shunt capacitor banks are eliminated by the synchronous technology. The IPFC takes the power factor the requirements of reactive power and the harmonic resonance protection as the switching criteria, thus the reactive power is well compensated and the frequent operating with light load an the harmonic resonance of power network are avoided. The experimental results demonstrate the excellent performance of reactive power compensation by this system.
{"title":"An intelligent reactive power compensator based on synchronous vacuum circuit breaker","authors":"Zou Ji-yan, Ding Fu-hua, Duan Xiong-ying","doi":"10.1109/DEIV.2004.1422619","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422619","url":null,"abstract":"A novel reactive power compensator is developed for 10kV distribution system to improve power quality. It is composed of a synchronous vacuum circuit breaker (SVCB) and an intelligent power factor controller (IPFC). Electrical transients for switching shunt capacitor banks are eliminated by the synchronous technology. The IPFC takes the power factor the requirements of reactive power and the harmonic resonance protection as the switching criteria, thus the reactive power is well compensated and the frequent operating with light load an the harmonic resonance of power network are avoided. The experimental results demonstrate the excellent performance of reactive power compensation by this system.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129728410","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422674
A. Goncharov, I. Brown
We describe some novel plasma devices based on the electrostatic plasma lens configuration and plasma optics principles. These low cost, high reliability, low maintenance devices can be used for manipulating heavy ion beams in a number of different applications for ion treatment and material surface modification.
{"title":"Novel plasma generation devices based on the plasma lens","authors":"A. Goncharov, I. Brown","doi":"10.1109/DEIV.2004.1422674","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422674","url":null,"abstract":"We describe some novel plasma devices based on the electrostatic plasma lens configuration and plasma optics principles. These low cost, high reliability, low maintenance devices can be used for manipulating heavy ion beams in a number of different applications for ion treatment and material surface modification.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128763511","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422673
M. Yalandin, S. Korovin, E.A. Lilvinov, G. Mesyats, A. Murzakaev, V. Rostov, V. Shpak, S. Shunailov
Emission properties of a graphite cathode supplied by voltage pulses with an amplitude of ˜300 kV, a pulse width of ˜10-9 and a pulse repetition frequency of up to 3.5 kHz, have been studied. The electron beam had a peak power of 0.6 GW and an average power of up to 3 kW. A single current pulse had energy of ˜1 J. Dynamics of the current emission delay in correlation with the charge transferred by the beam has been analyzed. The cathode surface morphology was checked with SEM.
{"title":"Study of explosive-emissive graphite cathodes in the pulsed-periodic operating regime","authors":"M. Yalandin, S. Korovin, E.A. Lilvinov, G. Mesyats, A. Murzakaev, V. Rostov, V. Shpak, S. Shunailov","doi":"10.1109/DEIV.2004.1422673","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422673","url":null,"abstract":"Emission properties of a graphite cathode supplied by voltage pulses with an amplitude of ˜300 kV, a pulse width of ˜10-9 and a pulse repetition frequency of up to 3.5 kHz, have been studied. The electron beam had a peak power of 0.6 GW and an average power of up to 3 kW. A single current pulse had energy of ˜1 J. Dynamics of the current emission delay in correlation with the charge transferred by the beam has been analyzed. The cathode surface morphology was checked with SEM.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128270521","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422616
YonPeng Meng, S. Jia, M. Rong
Vibration analysis is a potential effective method for condition monitoring of circuit breakers (CBs). In this paper, a time-frequency method using an algorithm of wavelet packet is applied in the subsequent analysis for vibration signals. The vibration signal collected on the framework of vacuum circuit breaker by an acceleration sensor is decomposed into individual frequency bands and those bands that contain the main signal energy are extracted to form individual condition eigenvector. All eigenvectors derived from various conditions are used for Condition classification of CBs. Based on this monitoring method, asynchronous feature between three poles have been simulated in a 35kV vacuum circuit breaker and difference between vibration signals during close operation with no-load and that with short-circuit current is investigated, which verify the feasibility and accuracy of the vibration analysis in condition monitoring of vacuum circuit breakers.
{"title":"Condition monitoring of vacuum circuit breakers using vibration analysis","authors":"YonPeng Meng, S. Jia, M. Rong","doi":"10.1109/DEIV.2004.1422616","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422616","url":null,"abstract":"Vibration analysis is a potential effective method for condition monitoring of circuit breakers (CBs). In this paper, a time-frequency method using an algorithm of wavelet packet is applied in the subsequent analysis for vibration signals. The vibration signal collected on the framework of vacuum circuit breaker by an acceleration sensor is decomposed into individual frequency bands and those bands that contain the main signal energy are extracted to form individual condition eigenvector. All eigenvectors derived from various conditions are used for Condition classification of CBs. Based on this monitoring method, asynchronous feature between three poles have been simulated in a 35kV vacuum circuit breaker and difference between vibration signals during close operation with no-load and that with short-circuit current is investigated, which verify the feasibility and accuracy of the vibration analysis in condition monitoring of vacuum circuit breakers.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"72 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120918048","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 : 1900-01-01DOI: 10.1109/DEIV.2004.1422645
H. Schellekens, S. Olive, K. P. Huy, P. Ndiaye, C. Pasqualini
Late breakdowns in vacuum interrupters after short circuit current interruption are studied with three methods. 1. High speed photography of the contact surface and the inter-electrode space to correlate the position of the restrike with respect to the prevailing conditions on the contact surface : 2. Spectrography during arcing and restrike to evaluate ionized particle densities and electron density ; and 3. A double imaging system to calculate the trajectories of droplets during the TRV phase. We found 95% of the restrikes to be associated with hydrogen in the inter-electrode gap at current zero, and remaining hot spots on the edge of the contact surface. We conclude the breakdown to be of a mixed Paschen type: partially in metal vapour of high density around hot spots and ignited by thermal electron emission, and partially in hydrogen gas which accumulates during arcing in the interrupter.
{"title":"Nature of late breakdowns in VI's after short circuit interruption","authors":"H. Schellekens, S. Olive, K. P. Huy, P. Ndiaye, C. Pasqualini","doi":"10.1109/DEIV.2004.1422645","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1422645","url":null,"abstract":"Late breakdowns in vacuum interrupters after short circuit current interruption are studied with three methods. 1. High speed photography of the contact surface and the inter-electrode space to correlate the position of the restrike with respect to the prevailing conditions on the contact surface : 2. Spectrography during arcing and restrike to evaluate ionized particle densities and electron density ; and 3. A double imaging system to calculate the trajectories of droplets during the TRV phase. We found 95% of the restrikes to be associated with hydrogen in the inter-electrode gap at current zero, and remaining hot spots on the edge of the contact surface. We conclude the breakdown to be of a mixed Paschen type: partially in metal vapour of high density around hot spots and ignited by thermal electron emission, and partially in hydrogen gas which accumulates during arcing in the interrupter.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124055992","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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