Pub Date : 2016-09-12DOI: 10.1109/DEIV.2016.7764034
B. Balhan, R. Barlow, J. Borburgh, G. Raffaele
At CERN, the SPS synchrotron is equipped with a slow extraction channel towards the fixed target beam lines in the North Area This channel includes five consecutive electrostatic septa, where the field free region and the active high field region are separated by an array of tungsten-rhenium wires. The field-free region provides for the circulating beam, while the high field region is used to deflect the extracted beam. Since the residual gas can be ionized by the orbiting beam, low energy ions could cross the wire array and enter the high field region and cause high voltage breakdown when accelerated onto the cathode. To prevent low energy ions from entering this high electric field region, a vertical field is applied to the orbiting beam using so-called `ion traps' for active protection. The vertical field is created by electrodes placed inside the region containing the circulating beam. Due to electromagnetic coupling onto the ion trap electrodes observed with the high frequency LHC beam (25 ns spaced bunches), the efficiency of the ion traps is greatly reduced. This leads to increased vacuum activity (electron cloud related) as well as high spark rates both in the main field and between the ion trap electrodes and their grounded support. In view of the SPS performance increase required for HL-LHC, this paper highlights the upgrades and improvements required to obtain a stable ion trap field and significantly reduce the number of breakdown events observed with the LHC beam in the accelerator.
{"title":"Improvement of the CERN SPS electrostatic septa ion traps","authors":"B. Balhan, R. Barlow, J. Borburgh, G. Raffaele","doi":"10.1109/DEIV.2016.7764034","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7764034","url":null,"abstract":"At CERN, the SPS synchrotron is equipped with a slow extraction channel towards the fixed target beam lines in the North Area This channel includes five consecutive electrostatic septa, where the field free region and the active high field region are separated by an array of tungsten-rhenium wires. The field-free region provides for the circulating beam, while the high field region is used to deflect the extracted beam. Since the residual gas can be ionized by the orbiting beam, low energy ions could cross the wire array and enter the high field region and cause high voltage breakdown when accelerated onto the cathode. To prevent low energy ions from entering this high electric field region, a vertical field is applied to the orbiting beam using so-called `ion traps' for active protection. The vertical field is created by electrodes placed inside the region containing the circulating beam. Due to electromagnetic coupling onto the ion trap electrodes observed with the high frequency LHC beam (25 ns spaced bunches), the efficiency of the ion traps is greatly reduced. This leads to increased vacuum activity (electron cloud related) as well as high spark rates both in the main field and between the ion trap electrodes and their grounded support. In view of the SPS performance increase required for HL-LHC, this paper highlights the upgrades and improvements required to obtain a stable ion trap field and significantly reduce the number of breakdown events observed with the LHC beam in the accelerator.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131091174","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 objective of this paper is to determine the arcing contact gap for a 126 kV horseshoe type bipolar axial magnetic field (AMF) vacuum interrupter. A pair of contacts with contact material of CuCr50 was arranged in a demountable vacuum chamber. Movable contact was driven by a spring driven permanent magnetic actuator. The full contact gap was 60 mm. Arc current reached up to 40 kA rms, and arc duration was set as 9ms. Evolution of vacuum arc behaviors was observed by a high-speed digital camera. A long arcing contact gap is the maximum gap above which vacuum arcs cannot be controlled by the bipolar AMF. A short arcing contact gap is the minimum gap below which vacuum arcs are constrict. Experimental results show that the long arcing contact gap of the horseshoe type AMF contact is determined as 35 mm, in which the vacuum arc can be controlled by the AMF effectively. The short arcing contact gap is determined as 14 mm. In addition, a recommended arcing contact gap without arc distorting outside is determined as 27 mm. The long arcing contact gap and short arcing contact gap can be used to determine opening speed curve of the 126 kV horseshoe type bipolar AMF vacuum interrupter.
本文的目的是确定126 kV马蹄型双极轴向磁场(AMF)真空灭弧器的电弧接触间隙。在可拆卸的真空室中设置一对触点，触点材料为CuCr50。活动触点由弹簧驱动的永磁驱动器驱动。全接触间隙为60mm。电弧电流达到40 kA rms，电弧持续时间设定为9ms。用高速数码相机观察了真空电弧行为的演变过程。长弧接触间隙是双极AMF不能控制真空弧的最大间隙。短弧接触间隙是真空弧收缩的最小间隙。实验结果表明，确定了马蹄形电涡流发生器的长弧接触间隙为35 mm，在此间隙内电涡流发生器可以有效地控制真空电弧。确定短弧接触间隙为14mm。此外，外部无电弧畸变的推荐电弧接触间隙确定为27mm。利用长电弧触点间隙和短电弧触点间隙可以确定126kv马蹄型双极AMF真空灭弧器的开断速度曲线。
{"title":"Effective arcing contact gap of a 126 kV horseshoe type axial magnetic field vacuum interrupter","authors":"Haomin Li, Yingsan Geng, Zhiyuan Liu, Chunhong Shen, Peng Li, Zhe Yang","doi":"10.1109/DEIV.2016.7748712","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748712","url":null,"abstract":"The objective of this paper is to determine the arcing contact gap for a 126 kV horseshoe type bipolar axial magnetic field (AMF) vacuum interrupter. A pair of contacts with contact material of CuCr50 was arranged in a demountable vacuum chamber. Movable contact was driven by a spring driven permanent magnetic actuator. The full contact gap was 60 mm. Arc current reached up to 40 kA rms, and arc duration was set as 9ms. Evolution of vacuum arc behaviors was observed by a high-speed digital camera. A long arcing contact gap is the maximum gap above which vacuum arcs cannot be controlled by the bipolar AMF. A short arcing contact gap is the minimum gap below which vacuum arcs are constrict. Experimental results show that the long arcing contact gap of the horseshoe type AMF contact is determined as 35 mm, in which the vacuum arc can be controlled by the AMF effectively. The short arcing contact gap is determined as 14 mm. In addition, a recommended arcing contact gap without arc distorting outside is determined as 27 mm. The long arcing contact gap and short arcing contact gap can be used to determine opening speed curve of the 126 kV horseshoe type bipolar AMF vacuum interrupter.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123166223","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7763962
Xian Cheng, Zhanqing Chen, G. Ge, Lian-yao Jiao
The current interruption capacity of gas gap can be enhanced by series connecting with vacuum gap in hybrid circuit breaker. For the purpose of compensating the inferior interruption performance of CO2 gas gap, as the substitute for SF6 gas gap, the interruption principle and the dielectric strength recovery process of the series gaps of vacuum gap and CO2 gas gap are studied in this paper. Based on the established test prototype, tests are carried on series gaps to investigate the influences of various arcing times, voltage-dividing capacitor, and CO2 gas pressure on its interruption performance via synthetic test circuit system. The test results convey that, CO2 gas gap with gas pressure at 0.8 Mpa can recover its dielectric strength faster and withstand higher recovery voltage under the effect of voltage-dividing capacitor while vacuum gap undertakes initial transient recovery voltage. But limited by the simple structure of gas interrupter and the interruption performance of CO2 gas, CO2 gas can't recover its dielectric strength rapidly.
{"title":"Investigation on the high current interruption principle for series gaps of vacuum gap and CO2 gas gap","authors":"Xian Cheng, Zhanqing Chen, G. Ge, Lian-yao Jiao","doi":"10.1109/DEIV.2016.7763962","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7763962","url":null,"abstract":"The current interruption capacity of gas gap can be enhanced by series connecting with vacuum gap in hybrid circuit breaker. For the purpose of compensating the inferior interruption performance of CO2 gas gap, as the substitute for SF6 gas gap, the interruption principle and the dielectric strength recovery process of the series gaps of vacuum gap and CO2 gas gap are studied in this paper. Based on the established test prototype, tests are carried on series gaps to investigate the influences of various arcing times, voltage-dividing capacitor, and CO2 gas pressure on its interruption performance via synthetic test circuit system. The test results convey that, CO2 gas gap with gas pressure at 0.8 Mpa can recover its dielectric strength faster and withstand higher recovery voltage under the effect of voltage-dividing capacitor while vacuum gap undertakes initial transient recovery voltage. But limited by the simple structure of gas interrupter and the interruption performance of CO2 gas, CO2 gas can't recover its dielectric strength rapidly.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117203460","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748708
Gleb A. Kumichev, I. N. Poluyanova
This paper compares characteristics of cold welding and welding formed due to prestrike with making current typical for capacitive load switching. Several CuCr contact materials manufactured using different technologies are investigated. The correlation between these characteristics and NSDD probability obtained in a synthetic single-phase scheme, imitating capacitive load switching in “O”, “CO for 600A/500Hz making current” and “CO for 3kA/500Hz making current” modes is studied in this paper. The connection between welding and dielectrical characteristics of different materials is demonstrated. Typical contact surface after the abovementioned operations for each of the studied materials is described.
{"title":"Investigation of welding characteristics and NSDD probabilities of different contact materials under capacitive load conditions","authors":"Gleb A. Kumichev, I. N. Poluyanova","doi":"10.1109/DEIV.2016.7748708","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748708","url":null,"abstract":"This paper compares characteristics of cold welding and welding formed due to prestrike with making current typical for capacitive load switching. Several CuCr contact materials manufactured using different technologies are investigated. The correlation between these characteristics and NSDD probability obtained in a synthetic single-phase scheme, imitating capacitive load switching in “O”, “CO for 600A/500Hz making current” and “CO for 3kA/500Hz making current” modes is studied in this paper. The connection between welding and dielectrical characteristics of different materials is demonstrated. Typical contact surface after the abovementioned operations for each of the studied materials is described.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127089649","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748674
A. Batrakov, S. Popov, E. Dubrovskaya
Ion energy distributions of different ion species in cathode-spot plasma were measured with using the HIDEN EQP300 analyzer in both the breakdown and arc modes of discharge in a vacuum gap with the Ga-In liquid-metal cathode simplifying repetitive discharge ignition. In the arc mode of discharge, the average charge of ions rises with increase of discharge current. This trend was found to be absent in the breakdown mode of discharge.
{"title":"Cathode spot plasma parameters in the breakdown stage of vacuum discharge","authors":"A. Batrakov, S. Popov, E. Dubrovskaya","doi":"10.1109/DEIV.2016.7748674","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748674","url":null,"abstract":"Ion energy distributions of different ion species in cathode-spot plasma were measured with using the HIDEN EQP300 analyzer in both the breakdown and arc modes of discharge in a vacuum gap with the Ga-In liquid-metal cathode simplifying repetitive discharge ignition. In the arc mode of discharge, the average charge of ions rises with increase of discharge current. This trend was found to be absent in the breakdown mode of discharge.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124940437","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7764032
V. Frolova, A. Nikolaev, E. Oks, K. Savkin, M. Shandrikov, A. Vizir, G. Yushkov
Boron plasmas are widely used in various ion beam and plasma technologies, including semiconductor ion doping. Of interest is also its use for deposition of hard coatings and surface modification to enhance the performance and lifetime of machine parts and tools. The paper reports on the generation of boron-rich plasma in a short high-current pulsed vacuum arc with a lanthanum hexaboride cathode, presents time-of-flight data on its mass-charge state, and discusses the influence of the arc parameters on the ion constitution of the boron-rich plasma.
{"title":"Boron-rich plasma of high current pulsed vacuum arc with lanthanum hexaboride cathode","authors":"V. Frolova, A. Nikolaev, E. Oks, K. Savkin, M. Shandrikov, A. Vizir, G. Yushkov","doi":"10.1109/DEIV.2016.7764032","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7764032","url":null,"abstract":"Boron plasmas are widely used in various ion beam and plasma technologies, including semiconductor ion doping. Of interest is also its use for deposition of hard coatings and surface modification to enhance the performance and lifetime of machine parts and tools. The paper reports on the generation of boron-rich plasma in a short high-current pulsed vacuum arc with a lanthanum hexaboride cathode, presents time-of-flight data on its mass-charge state, and discusses the influence of the arc parameters on the ion constitution of the boron-rich plasma.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125031551","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748716
Bingzhou Wu, Z. Shi, Cong Wang, S. Jia, Lijun Wang
The splitting and threshold currents (Is and Ithr, respectively) carried by a single cathode spot of vacuum arcs under the influence of an external axial magnetic field (AMF) up to 220mT are investigated experimentally. Experiments are conducted with OFHC copper and CuCr25 butt electrodes in a demountable vacuum chamber. The electrode separation is fixed at 6 mm. The spots are photographed using a high-speed framing camera with an exposure time of 2 μs. The uniform AMF (Bn) is applied by means of Nd-Fe-B permanent magnets placed symmetrically inside the chamber. It is found that for either cathode material, with increasing Bn, the splitting current Is initially (0 ≤ Bn ≤ 20 mT) declines rapidly. It then remains basically constant. For both cathode materials, the threshold current Ithr exhibits a similar trend to the splitting current Is. A possible explanation is proposed to account for the above results.
{"title":"Experimental investigation on the current of cathode spot of vacuum arc in axial magnetic fields","authors":"Bingzhou Wu, Z. Shi, Cong Wang, S. Jia, Lijun Wang","doi":"10.1109/DEIV.2016.7748716","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748716","url":null,"abstract":"The splitting and threshold currents (I<sub>s</sub> and I<sub>thr</sub>, respectively) carried by a single cathode spot of vacuum arcs under the influence of an external axial magnetic field (AMF) up to 220mT are investigated experimentally. Experiments are conducted with OFHC copper and CuCr25 butt electrodes in a demountable vacuum chamber. The electrode separation is fixed at 6 mm. The spots are photographed using a high-speed framing camera with an exposure time of 2 μs. The uniform AMF (B<sub>n</sub>) is applied by means of Nd-Fe-B permanent magnets placed symmetrically inside the chamber. It is found that for either cathode material, with increasing B<sub>n</sub>, the splitting current I<sub>s</sub> initially (0 ≤ B<sub>n</sub> ≤ 20 mT) declines rapidly. It then remains basically constant. For both cathode materials, the threshold current I<sub>thr</sub> exhibits a similar trend to the splitting current I<sub>s</sub>. A possible explanation is proposed to account for the above results.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125150813","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7763965
E. Taylor, Joachim Oemisch, M. Eiselt, Marco Hinz
Circuit breakers using vacuum interrupters (VI) are often tested according to the IEC standard 62271-100. This standard specifies a series of current interruption tests to verify the operation of the circuit breaker under a variety of different failure conditions. The IEC 62271-100 standard will be updated at the end of 2016 to include additional new tests for medium voltage circuit breakers, designed to verify successful interruption in electrical power systems with an effectively earthed neutral. In the current version of the standard, three-phase tests are performed in the non-effectively earthed neutral case. This situation is referred to as kpp = 1.5, where kpp is the first-pole-to-clear factor. In the updated standard, additional three-phase tests are performed with an effectively earthed neutral, referred to as kpp = 1.3. This setup leads to higher stress on the second phase to clear. In order to evaluate the effect of the new tests, two different VI designs, in regular commercial use which previously passed the 62271-100 standard, were tested according to the new requirements. One VI style was an axial magnetic field (AMF) design for 40.5kV/31.5kA, and the other a radial magnetic field (RMF) design for 17.5kV/31.5kA. Both VI designs were first tested with symmetric and asymmetric close/open operations for kpp = 1.5. The VI's were then tested with symmetric operations (T100s) and a large number of asymmetric operations (T100a) with kpp = 1.3. Both VI types passed these test duties, which greatly exceeded the requirements of the updated IEC 62271-100. This performance indicates that well-designed VI's that pass the current version of IEC 62271-100 will also be able to pass the new kpp = 1.3 tests for systems with an effectively earthed neutral.
{"title":"Performance of vacuum interrupters in electrical power systems with an effectively earthed neutral","authors":"E. Taylor, Joachim Oemisch, M. Eiselt, Marco Hinz","doi":"10.1109/DEIV.2016.7763965","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7763965","url":null,"abstract":"Circuit breakers using vacuum interrupters (VI) are often tested according to the IEC standard 62271-100. This standard specifies a series of current interruption tests to verify the operation of the circuit breaker under a variety of different failure conditions. The IEC 62271-100 standard will be updated at the end of 2016 to include additional new tests for medium voltage circuit breakers, designed to verify successful interruption in electrical power systems with an effectively earthed neutral. In the current version of the standard, three-phase tests are performed in the non-effectively earthed neutral case. This situation is referred to as kpp = 1.5, where kpp is the first-pole-to-clear factor. In the updated standard, additional three-phase tests are performed with an effectively earthed neutral, referred to as kpp = 1.3. This setup leads to higher stress on the second phase to clear. In order to evaluate the effect of the new tests, two different VI designs, in regular commercial use which previously passed the 62271-100 standard, were tested according to the new requirements. One VI style was an axial magnetic field (AMF) design for 40.5kV/31.5kA, and the other a radial magnetic field (RMF) design for 17.5kV/31.5kA. Both VI designs were first tested with symmetric and asymmetric close/open operations for kpp = 1.5. The VI's were then tested with symmetric operations (T100s) and a large number of asymmetric operations (T100a) with kpp = 1.3. Both VI types passed these test duties, which greatly exceeded the requirements of the updated IEC 62271-100. This performance indicates that well-designed VI's that pass the current version of IEC 62271-100 will also be able to pass the new kpp = 1.3 tests for systems with an effectively earthed neutral.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126750129","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748756
S. Popov, A. Schneider, V. Lavrinovich, A. Batrakov, S. Gortschakow, A. Khakpour
Transition process from a diffuse to anode spot mode in high-current vacuum arc discharge with Cu-Cr electrodes has been studied experimentally. Images of the arc were recorded with a frequency of about 25000 frames per second synchronously with the acquisition of current and voltage waveforms. Experiments clarify that after the current reaches a certain threshold value (4 to 5 kA for bulk-type, 2-cm electrodes), the arc discharge passes from diffuse mode to the mode with anode spot and voltage increased by ~20 V. In this mode, bright anode jet appears; cathode micro spots are reduced in number and grouped in front of the anode jet with the formation the cathode macro spot. In such a threshold regime, the discharge can change to the anode-spot mode and back to diffuse mode many times, with transition time in the microsecond range. With increasing current amplitude, anode spot mode becomes more stable, cathode and anode macro-jets are coming closer together forming a quasi-continuous radially-constricted discharge channel. The constriction of discharge is accompanied by increasing power density on both electrodes. In the case of TMF type electrodes, the constricted plasma channel moves azimuthally along the electrode lobe.
{"title":"Fast video registration of transition processes from diffuse mode to anode spot mode in high-current arc with copper-chromium electrodes","authors":"S. Popov, A. Schneider, V. Lavrinovich, A. Batrakov, S. Gortschakow, A. Khakpour","doi":"10.1109/DEIV.2016.7748756","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748756","url":null,"abstract":"Transition process from a diffuse to anode spot mode in high-current vacuum arc discharge with Cu-Cr electrodes has been studied experimentally. Images of the arc were recorded with a frequency of about 25000 frames per second synchronously with the acquisition of current and voltage waveforms. Experiments clarify that after the current reaches a certain threshold value (4 to 5 kA for bulk-type, 2-cm electrodes), the arc discharge passes from diffuse mode to the mode with anode spot and voltage increased by ~20 V. In this mode, bright anode jet appears; cathode micro spots are reduced in number and grouped in front of the anode jet with the formation the cathode macro spot. In such a threshold regime, the discharge can change to the anode-spot mode and back to diffuse mode many times, with transition time in the microsecond range. With increasing current amplitude, anode spot mode becomes more stable, cathode and anode macro-jets are coming closer together forming a quasi-continuous radially-constricted discharge channel. The constriction of discharge is accompanied by increasing power density on both electrodes. In the case of TMF type electrodes, the constricted plasma channel moves azimuthally along the electrode lobe.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115054536","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748709
Hui Ma, Zaiqin Zhang, S. Ferrari, Jianhua Wang, Yingsan Geng, Zhiyuan Liu
The objective of this paper is to propose a new method to quantitatively determine the arcing rotation velocity of the constricted vacuum arc driven by a transverse magnetic field (TMF). This method is based on a split anode and TMF cathode configuration system. Experiments were set in a demountable vacuum chamber. Both electrodes have a contact diameter of 60 mm. The anode surface was divided into four regions: one central region (Area I) and three symmetrically peripheral annular regions (Area II, III and IV). The currents of the four areas on the anode contact were measured using four Rogowski coils situated outside the vacuum chamber. The observed arc modes were recorded by a high-speed CCD video camera. The rotation velocity of the constricted arc column is calculated from the arc current waveforms of the four split areas. The experimental results indicate that the maximum speed is approximately 471 m/s with the arc current of 16 kA rms. The results also reveal the corresponding anode current distribution characteristics under TMF in different arc stages during the arcing time.
本文的目的是提出一种定量确定横向磁场驱动的收缩真空电弧的电弧旋转速度的新方法。该方法是基于一个分裂阳极和TMF阴极配置系统。实验在可拆卸的真空室中进行。两个电极的接触直径均为60mm。阳极表面分为四个区域:一个中心区域(区域I)和三个对称的外围环形区域(区域II, III和IV)。阳极接触上的四个区域的电流使用位于真空室外的四个Rogowski线圈进行测量。用高速CCD摄像机记录了观测到的电弧模式。根据四个分裂区域的电弧电流波形计算出压缩弧柱的旋转速度。实验结果表明，电弧电流为16 kA rms，最大速度约为471 m/s。结果还揭示了电弧时间内不同电弧阶段在TMF作用下对应的阳极电流分布特征。
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