Protection Considerations of High Power Vacuum Tubes Against Reflected Power Fault

Document Type : Original Article

Author

sharif university

Abstract

The ceramic fracture in output RF1 window is one of the most important failure factors in high power vacuum tubes. Fast protection systems are used to protect the tube. These protection systems are activated with some measured variables such as the level of backward RF power. On the other hand, a fast protection system can be activated with noise. Therefore, a tradeoff must be done between the response time of the protection system and its sensitivity to the noise. There are many methods to determine the response time of the protection system. The level of allowable power loss in the tube failure process is one of the conventional figures of merit for protection response time determination. However, these methods are conservative and the resulted response time is usually less than the critical time which is necessary for protecting the tube. In this paper, an experimental investigation is presented about the relation between the response time of the tube protection system and the crack growth in the ceramic of RF window. It is shown that the twin growth in ceramic can be a reliable figure of merit for the response time calculation of the tube protection system.    

Keywords

References

[1]     H. Zibaeinejad, H. Abiri, “Analysis of Cathode Shape Effect on the Performance of Realistic Magnetron,” Scientific Journal of Radar., Vol. 5, No. 4, 2018 (in persion).##
[2]     A. Farajzadeh, S. Kaboli, “Analysis of Spark Gap Shape Effect on the Output Voltage of Blumlein Bipolar Pulse Former,” Scientific Journal of applied electromagnetics, Vol. 7, No. 2, 2020 (in persion).##
[3]     S. Mohsenzade, M. Zarghany, and S. Kaboli, “A Series Stacked IGBT Switch With Robustness Against Short-Circuit Fault for Pulsed Power Applications,” IEEE Transactions on  Power Electronics., Vol. 33, No. 5, pp. 3779–3790, 2018.##
[4]     Y. Satio, N. Matuda, S. Anami, A. Kinbara, J. Horikoshi, J. Tanaka, “Breakdown of alumina RF windows”, IEEE Transactions on Electrical Insulation., Vol. 24, No. 6, pp. 1029–1032, 1989.##
[5]     S. R. Jang, J. H. Seo, and H. J. Ryoo, “Development of 50-kV 100-kW Three-Phase Resonant Converter for 95-GHz Gyrotron,” IEEE Transactions on Industrial Electronics, Vol. 63, No. 11, pp. 6674–6683, 2016.##
[6]     S. Mohsenzade, M. Zarghany, M. Aghaei, and S. Kaboli, “A High-Voltage Pulse Generator with Continuously Variable Pulsewidth Based on a Modified PFN,” IEEE Transactions on Plasma Science, Vol. 45, No. 5, pp. 849–858, 2017.##
[7]     K. Pouresmaeil and S. Kaboli, “A Reopened Crowbar Protection for Increasing the Resiliency of the Vacuum Tube High-Voltage DC Power Supply Against the Vacuum Arc,” IEEE Transactions on Plasma Science, Vol. 47, No. 5, pp. 2717–2725, 2019.##
[8]     S. Mohsenzade, M. Zarghani, and S. Kaboli, “A Voltage Balancing Scheme for Series-connected IGBTs to Increase Their Expected Lifetime in Pulsed Load Applications,” IEEE Journal of Emerging and Selected Topics in Power Electronics, Vol. 9, No. 1, pp. 461–471, 2021.##
[9]     F. Zhao, L. Wang, D. Fan, B. X. Bie, X. M. Zhou, T. Suo, Y. L. Li, M. W. Chen, C. L. Liu, M. L. Oi, M. H. Zhu, S. N. Luo, “Macrodeformation Twins in Single-Crystal Aluminum”, Physical Review Letter, Vol. 116, No. 7, pp. 075501-1-075501-5, 2016.##
[10]  H. Matsuo, M. Mitsuhara, K. Ikeda, S. Hatab, H. Nakashima, “Electron microscopy analysis for crack propagation behavior of alumina,” International Journal of Fatigue, 32, pp. 592-598, 2010.##
[11]  H. Ao, H. Asano, F. Naito, N. Ouchi, J. Tamura, K. Takata, “Impedance matching of pillbox-type RF windows and direct measurement of the ceramic relative dielectric constant,” Nuclear Instruments and Methods in Physics Research. Section A, 737, pp. 65-70, 2014.##
[12]  J. Castaing, A. He, K. P. D. Lagerlof, A. H. Heuer, “Deformation of sapphire (a-Al2O3) by basal slip and basal twining below 700oC”, Philosophical Magazine, Vol. 84, No. 11, pp. 1113–1125, 2004.##

Files

History

  • Receive Date: 28 March 2020
  • Revise Date: 21 July 2020
  • Accept Date: 01 August 2020

Share

How to cite

Statistics