Pub Date : 2017-10-10DOI: 10.1109/PPC.2017.8291314
F. P. Mohamed, W. H. Siew, B. Sheng, B. Stewart, E. Morris
The breakdown of insulation in cables while in service can cause considerable damage to equipment and the accessories to which they are connected. PD in cables arises due to the overstressing of cable insulation resulting from electric field enhancement caused by imperfections in cable core and screen. The nature and magnitude of PD activity depends upon the type of defect, aging, environmental factors, applied voltage and cable loading. Reduction in system voltage can potentially reduce PD, which will correspondingly extend the service life of the cable. Currently, industry voltage statutory requirements permit ±6% tolerance setting on nominal voltage on distribution networks. This ±6% voltage reduction on may have little or an adverse effect on PD magnitude depending on the nature of defect present in the cable. Hence there is a clear requirement to pre-determine the PD inception voltage in cables through laboratory experiments to understand the significance of voltage reduction. This means to verify the effect of voltage reduction on extinguishing or minimizing PD activity in cables. In this paper, range of voltages at which PD incepts termed as partial discharge inception voltage(PDIV) is measured using a test cell containing different types of electrode configuration having different spacing. PDIV measured using the test cell is verified by conducting partial discharge testing in paper insulated lead covered (PILC) and cross-linked poly ethylene(XLPE) cables. It has been found that PDIV measured using the test cell and cable are in good agreement.
{"title":"Pre-determination of partial discharge inception voltage in power cables using electrode gaps in air under AC voltage","authors":"F. P. Mohamed, W. H. Siew, B. Sheng, B. Stewart, E. Morris","doi":"10.1109/PPC.2017.8291314","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291314","url":null,"abstract":"The breakdown of insulation in cables while in service can cause considerable damage to equipment and the accessories to which they are connected. PD in cables arises due to the overstressing of cable insulation resulting from electric field enhancement caused by imperfections in cable core and screen. The nature and magnitude of PD activity depends upon the type of defect, aging, environmental factors, applied voltage and cable loading. Reduction in system voltage can potentially reduce PD, which will correspondingly extend the service life of the cable. Currently, industry voltage statutory requirements permit ±6% tolerance setting on nominal voltage on distribution networks. This ±6% voltage reduction on may have little or an adverse effect on PD magnitude depending on the nature of defect present in the cable. Hence there is a clear requirement to pre-determine the PD inception voltage in cables through laboratory experiments to understand the significance of voltage reduction. This means to verify the effect of voltage reduction on extinguishing or minimizing PD activity in cables. In this paper, range of voltages at which PD incepts termed as partial discharge inception voltage(PDIV) is measured using a test cell containing different types of electrode configuration having different spacing. PDIV measured using the test cell is verified by conducting partial discharge testing in paper insulated lead covered (PILC) and cross-linked poly ethylene(XLPE) cables. It has been found that PDIV measured using the test cell and cable are in good agreement.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133848862","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291096
J. Koutsoubis, J. Gray, N. Kokkinos, D. Kokkinos
A switch module assembly utilizing a power crowbar circuit and high-pressure plasma closing switch technology has been designed, constructed and tested. The switch module is the central block of a lightning impulse current generator under development, capable of producing a 10/350μs waveform at a peak magnitude in excess of 200kA (W/R = WMJ/Ω). The circuit consists of two separately charged capacitor banks, a fast start bank and a slow sustain bank responsible for the generation of the pulse wave-front and wave-tail respectively. These are switched in sequence to the load by means of two electrically triggered, graphite electrode high-action integral spark gap switches. The switch module assembly was tested for a number of different switch parameters and circuit operation modes. The produced output current pulse had a magnitude of 30kA for a start and sustain capacitor bank charging voltages of −40kV and +3.5kV respectively. In addition, the operational performance and trigger range characteristics of the two switches were investigated.
{"title":"Development and testing of a 200kA, 10/350μs lightning impulse current generator switch module","authors":"J. Koutsoubis, J. Gray, N. Kokkinos, D. Kokkinos","doi":"10.1109/PPC.2017.8291096","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291096","url":null,"abstract":"A switch module assembly utilizing a power crowbar circuit and high-pressure plasma closing switch technology has been designed, constructed and tested. The switch module is the central block of a lightning impulse current generator under development, capable of producing a 10/350μs waveform at a peak magnitude in excess of 200kA (W/R = WMJ/Ω). The circuit consists of two separately charged capacitor banks, a fast start bank and a slow sustain bank responsible for the generation of the pulse wave-front and wave-tail respectively. These are switched in sequence to the load by means of two electrically triggered, graphite electrode high-action integral spark gap switches. The switch module assembly was tested for a number of different switch parameters and circuit operation modes. The produced output current pulse had a magnitude of 30kA for a start and sustain capacitor bank charging voltages of −40kV and +3.5kV respectively. In addition, the operational performance and trigger range characteristics of the two switches were investigated.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"281 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131482060","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291090
A. Akimov, P. Bak, M. Egorychev, P. Kolesnikov, V. Logunov, O. Nikitin
The pulse forming networks (PFNs) were developed to provide a 2 kA, 20 MeV linear induction accelerator cells power supply. A PFN's and high-voltage capacitors manufacturing is organized at BINP. The PFN is a LC-network with nonuniform impedance made of capacitive sections with a combined paper-film dielectric filled with a castor oil in a polypropylene case. A PFN's isolation is rated at 50 kV charging voltage. The two types of PFNs are developed for 60 and 380 ns flattop duration. They are capable of producing the pulses up to 21 kV, 10 kA with a ±0.5–1% flattop voltage uniformity at a complex inductive-resistive load of the accelerating cell. The PFNs test results in the nominal regime are presented. The PFNs life test results at a higher electrical field in the dielectric are described.
脉冲形成网络(pfn)用于提供2 kA, 20 MeV的线性感应加速器电池电源。在BINP组织了PFN和高压电容器的制造。PFN是一种具有非均匀阻抗的lc -网络，由电容部分与在聚丙烯外壳中填充蓖麻油的复合纸膜介质组成。PFN的隔离额定充电电压为50kv。两种类型的pfn分别用于60和380 ns的平顶持续时间。它们能够在加速电池的复杂电感-电阻负载下以±0.5-1%的平顶电压均匀性产生高达21 kV, 10 kA的脉冲。给出了在标称工况下PFNs的试验结果。介绍了PFNs在较高电介质电场下的寿命试验结果。
{"title":"PULSE forming networks development for a 60–380 ns pulsed power supply for 2 ka 20 mev linear induction accelerator","authors":"A. Akimov, P. Bak, M. Egorychev, P. Kolesnikov, V. Logunov, O. Nikitin","doi":"10.1109/PPC.2017.8291090","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291090","url":null,"abstract":"The pulse forming networks (PFNs) were developed to provide a 2 kA, 20 MeV linear induction accelerator cells power supply. A PFN's and high-voltage capacitors manufacturing is organized at BINP. The PFN is a LC-network with nonuniform impedance made of capacitive sections with a combined paper-film dielectric filled with a castor oil in a polypropylene case. A PFN's isolation is rated at 50 kV charging voltage. The two types of PFNs are developed for 60 and 380 ns flattop duration. They are capable of producing the pulses up to 21 kV, 10 kA with a ±0.5–1% flattop voltage uniformity at a complex inductive-resistive load of the accelerating cell. The PFNs test results in the nominal regime are presented. The PFNs life test results at a higher electrical field in the dielectric are described.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133007700","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291306
P. Macinnes, V. Bratman, L. Zhang, G. Denisov, W. He, N. G. Kolganov, M. McStravick, S. Mishakin, C. Robertson, S. Samsonov, C. Whyte, A. Young, K. Ronald, A. Phelps, A. Cross
Backward Wave Oscillators (BWO's) utilizing moderately relativistic (~550kV), high-current (~10 kA) electron beams are capable of producing hundreds of MWs of pulsed radiation in the centimeter wavelength range. Such relativistic BWOs (RBWOs) allow for broadband, smooth, frequency-tuning via adjustment of the accelerating potential; making them an attractive source for use in frequency-swept pulse compression. This paper presents results of a 2.86m long 5-fold helically corrugated, dispersive pulse compressor where a maximum power compression ratio of 25 was achieved by compressing an input microwave pulse of 80 ns duration swept from 9.65 GHz to 9.05 GHz into a 1.6ns Gaussian-envelope pulse. For an average input power of 5.8 kW generated by a conventional traveling wave tube amplifier, a peak pulse output power of 145 kW was measured corresponding to an energy efficiency of 66%. An X-band relativistic BWO, designed to drive a 0.97m long 5-fold compressor, was built and tested using the accelerating potential generated by a SINUS-6 highcurrent accelerator. The experimental RBWO operated close to the predicted power of 700MW with its oscillation frequency varied from 10 to 9.6GHz via the falling edge of the voltage pulse. It was demonstrated that the ~15ns duration frequency-swept part of the RBWO pulse was effectively compressed resulting in a 4.5-fold peak power increase with a maximum power of 3.2 GW generated. The potential for a 5-fold helical waveguide to compress longer duration pulses generated by a RBWO is discussed.
{"title":"Periodic GW level microwave pulses in X-band from a combination of a relativistic backward wave oscillator and a helical waveguide compressor","authors":"P. Macinnes, V. Bratman, L. Zhang, G. Denisov, W. He, N. G. Kolganov, M. McStravick, S. Mishakin, C. Robertson, S. Samsonov, C. Whyte, A. Young, K. Ronald, A. Phelps, A. Cross","doi":"10.1109/PPC.2017.8291306","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291306","url":null,"abstract":"Backward Wave Oscillators (BWO's) utilizing moderately relativistic (~550kV), high-current (~10 kA) electron beams are capable of producing hundreds of MWs of pulsed radiation in the centimeter wavelength range. Such relativistic BWOs (RBWOs) allow for broadband, smooth, frequency-tuning via adjustment of the accelerating potential; making them an attractive source for use in frequency-swept pulse compression. This paper presents results of a 2.86m long 5-fold helically corrugated, dispersive pulse compressor where a maximum power compression ratio of 25 was achieved by compressing an input microwave pulse of 80 ns duration swept from 9.65 GHz to 9.05 GHz into a 1.6ns Gaussian-envelope pulse. For an average input power of 5.8 kW generated by a conventional traveling wave tube amplifier, a peak pulse output power of 145 kW was measured corresponding to an energy efficiency of 66%. An X-band relativistic BWO, designed to drive a 0.97m long 5-fold compressor, was built and tested using the accelerating potential generated by a SINUS-6 highcurrent accelerator. The experimental RBWO operated close to the predicted power of 700MW with its oscillation frequency varied from 10 to 9.6GHz via the falling edge of the voltage pulse. It was demonstrated that the ~15ns duration frequency-swept part of the RBWO pulse was effectively compressed resulting in a 4.5-fold peak power increase with a maximum power of 3.2 GW generated. The potential for a 5-fold helical waveguide to compress longer duration pulses generated by a RBWO is discussed.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124297264","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291168
E. Morris, W. H. Siew
The majority of PD monitoring is performed on cables operating under AC conditions, however, the increasing use of high voltage DC links, for subsea, or long land-based connections provides motivation for the increased use of PD monitoring on cables operating under HVDC. However, despite the increased intensity of research into PD in HVDC cables, there are significant knowledge gaps, preventing the practical application of PD monitoring techniques to HVDC cables. This paper seeks to partially address these gaps in knowledge, by presenting results obtained from PD measurements on artificial voids created in polymeric cable insulation under both AC and DC conditions. This work was presented at the 21st IEEE International Pulsed Power Conference.
{"title":"A comparison of AC and DC partial discharge activity in polymeric cable insulation","authors":"E. Morris, W. H. Siew","doi":"10.1109/PPC.2017.8291168","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291168","url":null,"abstract":"The majority of PD monitoring is performed on cables operating under AC conditions, however, the increasing use of high voltage DC links, for subsea, or long land-based connections provides motivation for the increased use of PD monitoring on cables operating under HVDC. However, despite the increased intensity of research into PD in HVDC cables, there are significant knowledge gaps, preventing the practical application of PD monitoring techniques to HVDC cables. This paper seeks to partially address these gaps in knowledge, by presenting results obtained from PD measurements on artificial voids created in polymeric cable insulation under both AC and DC conditions. This work was presented at the 21st IEEE International Pulsed Power Conference.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133944152","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291174
J. Smith, E. Ormond, K. Hogge
The Cygnus Dual Beam Radiographic Facility includes two identical radiographic sources — Cygnus 1 and Cygnus 2. Cygnus is the radiography source used in Subcritical Experiments (SCEs) at the Nevada National Security Site (NNSS). The machine specifications are: Electric 2.25 MV, 60 kA, 60 ns; Radiation 4 Rad, 1 mm, 50 ns; Operation single shot, 2-shots/day. Cygnus has operated at the NNSS since February 2004. In this period, it has participated on five SCE experiments — Armando, Bacchus, Barolo A, Barolo B, and Pollux. SCE projects typically require over a hundred preparatory shots culminating in a single high-fidelity or SCE shot, and typically take over a year for completion. Therefore, SCE shots are high risk and high value making reliability and reproducibility utmost priority. In this regard, major effort is focused on operational performance. A quantitative performance measurement is valuable for tracking and maintaining Cygnus preparedness. In this work, we present a new model for analysis of Cygnus performance. This model uses x-ray dose distribution as the basis for calculation of reliability, record, and reproducibility. It will be applied both to longterm (historical) and short-term (readiness) periods for each of the five SCEs.
天鹅座双光束射线照相设备包括两个相同的射线照相源-天鹅座1和天鹅座2。天鹅座是内华达州国家安全基地(NNSS)亚临界实验(SCEs)中使用的射线照相源。整机规格为:电动2.25 MV、60 kA、60 ns;辐射4 Rad, 1 mm, 50 ns;操作单针，2针/天。天鹅座从2004年2月开始在NNSS运行。在此期间，它参与了五个SCE实验- Armando, Bacchus, Barolo A, Barolo B和Pollux。SCE项目通常需要超过100个准备镜头，最终以一个高保真或SCE镜头结束，通常需要一年多的时间才能完成。因此，SCE拍摄是高风险和高价值的，可靠性和可重复性是最重要的。在这方面，主要的努力集中在业务绩效上。定量的性能测量对于跟踪和维护Cygnus准备是有价值的。在这项工作中，我们提出了一个新的模型来分析Cygnus的性能。该模型使用x射线剂量分布作为计算可靠性、记录性和再现性的基础。它将同时适用于5个企业管理系统的长期(历史)和短期(准备就绪)阶段。
{"title":"Cygnus performance on five Subcritical Experiments","authors":"J. Smith, E. Ormond, K. Hogge","doi":"10.1109/PPC.2017.8291174","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291174","url":null,"abstract":"The Cygnus Dual Beam Radiographic Facility includes two identical radiographic sources — Cygnus 1 and Cygnus 2. Cygnus is the radiography source used in Subcritical Experiments (SCEs) at the Nevada National Security Site (NNSS). The machine specifications are: Electric 2.25 MV, 60 kA, 60 ns; Radiation 4 Rad, 1 mm, 50 ns; Operation single shot, 2-shots/day. Cygnus has operated at the NNSS since February 2004. In this period, it has participated on five SCE experiments — Armando, Bacchus, Barolo A, Barolo B, and Pollux. SCE projects typically require over a hundred preparatory shots culminating in a single high-fidelity or SCE shot, and typically take over a year for completion. Therefore, SCE shots are high risk and high value making reliability and reproducibility utmost priority. In this regard, major effort is focused on operational performance. A quantitative performance measurement is valuable for tracking and maintaining Cygnus preparedness. In this work, we present a new model for analysis of Cygnus performance. This model uses x-ray dose distribution as the basis for calculation of reliability, record, and reproducibility. It will be applied both to longterm (historical) and short-term (readiness) periods for each of the five SCEs.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"14 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124522544","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291173
Y. Kim, H. Herrmann, M. Kaufman, R. Howe, C. Young, R. Malone, J. A. Green, T. Haines
An Aerogel Cherenkov Detector for Cygnus (ACD/C) has been developed to provide time-dependent x-ray spectral information from Cygnus — an intense flash x-ray source operated at the Nevada National Security Site. Time-resolved Cygnus x-ray signals were measured at three energy thresholds: 1.3 MeV (by 197 mg/cc aerogel), 1.1 MeV (by 260 mg/cc aerogel), and 0.3 MeV (by quartz). ACD/C data qualitatively suggest that the high-energy x-ray peak exists on a shorter timescale than the Cygnus voltage or current pulse. A time-dependent, x-ray spectral information can improve the understanding of the physics of dense objects radiography.
{"title":"Time-resolved measurements of Cygnus x-ray production using Aerogel Cherenkov Detector","authors":"Y. Kim, H. Herrmann, M. Kaufman, R. Howe, C. Young, R. Malone, J. A. Green, T. Haines","doi":"10.1109/PPC.2017.8291173","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291173","url":null,"abstract":"An Aerogel Cherenkov Detector for Cygnus (ACD/C) has been developed to provide time-dependent x-ray spectral information from Cygnus — an intense flash x-ray source operated at the Nevada National Security Site. Time-resolved Cygnus x-ray signals were measured at three energy thresholds: 1.3 MeV (by 197 mg/cc aerogel), 1.1 MeV (by 260 mg/cc aerogel), and 0.3 MeV (by quartz). ACD/C data qualitatively suggest that the high-energy x-ray peak exists on a shorter timescale than the Cygnus voltage or current pulse. A time-dependent, x-ray spectral information can improve the understanding of the physics of dense objects radiography.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121518855","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291278
R. J. Alleni, D. Hinshelwood, S. Jackson, P. Ottinger, H. M. Rittersdorf, J. Schumer
Well diagnosed measurements of electrical breakdown between metal electrodes in vacuum have been made using a 1-MV, 50-ns pulse-generator-based test stand [1]. Results with bare, as-machined electrodes showed that cathode surface finish and material have little to no effect on the breakdown electric field. However, changing the AK gap did affect the breakdown field level, suggesting that the anode is involved in cathode turn on. Further tests showed that applying a carbon coating to the anode can dramatically decrease the breakdown field [2]. Here, we report on other anode and cathode surface treatments and how they can enhance or suppress breakdown. Polishing of the anode can prevent breakdown at certain field strengths and decrease the breakdown current at higher fields. Marring a small spot on a polished anode is shown to initiate cathode turn on at a location opposite that spot. The effects of other surface treatments such as metallic and dielectric coatings on anode and cathode surfaces will also be discussed.
{"title":"Effects of anode and cathode surface treatments on vacuum breakdown between metal electrodes with 50-ns high voltage pulses","authors":"R. J. Alleni, D. Hinshelwood, S. Jackson, P. Ottinger, H. M. Rittersdorf, J. Schumer","doi":"10.1109/PPC.2017.8291278","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291278","url":null,"abstract":"Well diagnosed measurements of electrical breakdown between metal electrodes in vacuum have been made using a 1-MV, 50-ns pulse-generator-based test stand [1]. Results with bare, as-machined electrodes showed that cathode surface finish and material have little to no effect on the breakdown electric field. However, changing the AK gap did affect the breakdown field level, suggesting that the anode is involved in cathode turn on. Further tests showed that applying a carbon coating to the anode can dramatically decrease the breakdown field [2]. Here, we report on other anode and cathode surface treatments and how they can enhance or suppress breakdown. Polishing of the anode can prevent breakdown at certain field strengths and decrease the breakdown current at higher fields. Marring a small spot on a polished anode is shown to initiate cathode turn on at a location opposite that spot. The effects of other surface treatments such as metallic and dielectric coatings on anode and cathode surfaces will also be discussed.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132572964","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291179
L. Lamy Rocha, H. Canacsinh, J. F. Silva, L. Redondo, T. Luciano
This paper presents a generalized n stage dynamic model for unipolar semiconductor based Marx generators. The model is tailored for the capacitors charging mode to enable the estimation of the maximum pulse repetition rate of the n stage generator. The maximum pulse repetition rate for the n stage Marx generator can be calculated as a function of the number n of stages, and of the voltage decay allowed in each capacitor (usually less than 10%). Furthermore, given a needed pulse repetition rate the model can estimate the optimum number of stages (n) so that the working voltage of each stage can be selected. Simulation results for a ten-stage (n=10) positive output Marx generators are presented and discussed.
{"title":"Modeling Marx generators for maximum pulse repetition rate estimation","authors":"L. Lamy Rocha, H. Canacsinh, J. F. Silva, L. Redondo, T. Luciano","doi":"10.1109/PPC.2017.8291179","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291179","url":null,"abstract":"This paper presents a generalized n stage dynamic model for unipolar semiconductor based Marx generators. The model is tailored for the capacitors charging mode to enable the estimation of the maximum pulse repetition rate of the n stage generator. The maximum pulse repetition rate for the n stage Marx generator can be calculated as a function of the number n of stages, and of the voltage decay allowed in each capacitor (usually less than 10%). Furthermore, given a needed pulse repetition rate the model can estimate the optimum number of stages (n) so that the working voltage of each stage can be selected. Simulation results for a ten-stage (n=10) positive output Marx generators are presented and discussed.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114667831","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 : 2017-06-18DOI: 10.1109/PPC.2017.8291202
D. Ceylan, M. U. Güdelek, O. Keysan
Barrel side and pulsed power supply module are two crucial parts of an electromagnetic launcher (EML), which affects the efficiency. One of the most important features in the barrel side is the shape of the armature. In this study, the shape of the armature is optimized by using independent variables to define the exact geometry of the armature. The main goal is to maximize the muzzle kinetic energy of the projectile. Armature geometry is divided into pieces which are used in the optimization algorithm as independent variables. Finite element method (FEM) is used to calculate the fitness function of the genetic algorithm (GA).
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