High Power Laser and Particle Beams, Volume. 36, Issue 11, 115014(2024)
Research on spherical graphite cast iron electrode based gas switch
Gas switches with high power capacity are the first choice for large-scale pulsed power devices at home and abroad, but the self-breakdown voltage jitter due to the randomness of gas discharge has always been the bottleneck problem for pulsed power devices. The electrode is the key to affect the stability and life of the gas switch, and the previous designs had to face the trade-off between low jitter and long life. This paper proposes a spherical graphite cast iron gas switch that takes into account the characteristics of low jitter and long life. Based on the characterization of the spherical graphite cast iron material, it is proposed that the uniform distribution of spherical graphite in the electrode is conducive to the mechanism of improving the breakdown stability of the gas switch, and the spherical graphite is uniformly distributed in the whole electrode, which has the native advantage of long life compared with the surface structure. A single-stage switching stability test experiment was designed and carried out, and the results show that the ductile graphite electrode can effectively reduce the heavy frequency self-breakdown jitter of 3%-4% in the traditional electrode structure to 2.5%. Ultimately, a 5-stage 1 MV equal self-breakdown probability type fully sealed gas switch was designed using low jitter ductile electrodes, and the switching jitter was further reduced to less than 2%. Under the test voltage range of 960-980 kV, discharge current of about 9 kA, and maintenance-free conditions, the switch was tested for 300 000 pulses, and the self-breakdown jitter was maintained at less than 2%, with an optimum of 1.7%. The switch conduction front is less than 5 ns, and the transmission efficiency is more than 90%. The results demonstrate the potential application of spherical graphite cast iron cathodes as gas switches.
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Wei Shang, Jiancang Su, Bo Zeng, Rui Li, Gang Wang, Jie Cheng, Yongdong Li, Mingzhu Gao, Binxiong Yu. Research on spherical graphite cast iron electrode based gas switch[J]. High Power Laser and Particle Beams, 2024, 36(11): 115014
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Received: Apr. 27, 2024
Accepted: Aug. 27, 2024
Published Online: Jan. 8, 2025
The Author Email: Jiancang Su (sujiancang@nint.ac.cn)