Discharge characteristics of a gas switch triggered by ejected plasma
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摘要: 利用内嵌微孔火花放电产生喷射等离子体、作用于两电极开关,研究了间隙距离、气压、气体种类、开关工作系数和电压极性配合等因素对等离子体喷射控制开关导通特性的影响。实验结果表明,等离子体喷射触发开关可在工作系数为10%的条件下可靠快速导通,当开关采用0.5 MPa_N2作为绝缘介质、间隙距离5 mm时,触发导通时延为11.7 μs,抖动为1.42 μs;当间隙距离增大到18 mm时,触发导通时延增大至19.7 μs,触发可靠性降低;当工作系数由10%增大到60%时,触发导通时延由11.7 μs降低至1.1 μs。在确保开关自击穿电压一致的前提下,短间隙、高气压、负触发脉冲电压、正工作电压更有利于减小开关触发导通时延。Abstract: High speed ejected plasma, generated by the discharge in an actuator, can be applied as a trigger to gas gap switch which is working at low coefficient or with wide gap. This paper studies the influence of working conditions of gas switch on the discharge characteristics of ejected plasma triggered gas switch .The effects of gap distance, gas type, gas pressure, switching coefficient and cooperation mode of trigger pulse polarity and main voltage polarity on the discharge characteristics of ejected plasma triggered gas switch were studied by experiments. The results indicate that the ejected plasma triggered gas switch can be reliably and rapidly triggered with switching coefficient of about 10% . When the gas pressure of N2 in the switch is 0.5 MPa and the gap distance is 5 mm, the delay time and jitter are 11.7 μs and 1.42 μs, respectively. When the distance increases to 18 mm, the probability is reduced, the delay time increases to 19.7 μs. When the switching coefficient increases from 10% to 60%, the delay time decreases from 11.7 μs to 1.1 μs. With the same self-breakdown voltage, high pressure, short gap distance, negative trigger pulse and positive main voltage are better best choices to reduce the delay time.
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Key words:
- ejected plasma /
- gas switch /
- gap distance /
- switching coefficient /
- discharge characteristics
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图 1 喷射等离子体触发气体开关结构及等离子体喷射腔结构
1-HV electrode; 2-ground electrode; 3-micro cavity; 4-connecting rod; 5-connecting rod; 6-insulative shell; 7-insulative shell; 8-insulative shell; 9-screw; 10-gas hole; 11-insulative ring; 12-needle electrode
Figure 1. Construction of the gas switch triggered by ejected plasma and structure of plasma ejection cavity
表 1 不同间隙距离下,主回路电压及开关触发导通概率
Table 1. main voltage and discharge probability at different gap distance
distance/mm main voltage/kV discharge number in 40 triggers discharge probability/% 5 −7 40 100 13 −20 38 95 15 −22 34 85 18 −27 28 70 表 2 不同气体种类和间隙气压下,开关的间隙距离
Table 2. Gap distance changes with gas type and pressure
gas pressure/MPa distance/mm SF6 0.2 12 0.3 8 0.5 5 N2 0.2 32 0.3 22 0.5 13 20% SF6+80% N2 0.2 16 0.3 11 0.5 7 表 3 不同工作模式下,工作电压与触发脉冲电压极性
Table 3. Polarities of main voltage and trigger pulse at different working mode
working mode polarities of main voltage polarities of trigger voltage Ⅰ negative positive Ⅱ positive negative Ⅲ positive positive Ⅳ negative negative -
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