Chen Zhi-Qiang, Jia Wei, Wu Wei, Mei Kai-Sheng, Guo Fan, Cheng Le, Wang Yi, Xie Lin-Shen, Wu Gang, Wang Ge-Fei, Shi Yue-Wu, Wang Wei
National Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, No. 28, Road Ping-Yu, District Ba-Qiao, Xi'an 710024, China.
Rev Sci Instrum. 2023 Nov 1;94(11). doi: 10.1063/5.0169862.
Coaxial peaking capacitor is a key component in high-altitude electromagnetic pulse (EMP) simulators with fast front pulse output. It poses significant technical and engineering challenges in limiting radiation field amplitude and test space. This paper presents the design and testing of a 180 pF, 3 MV coaxial peaking capacitor with improved insulation performance. In the insulation design, the length of the dielectric film is extended to reduce the background electric field on the flashover path. The electric field threshold obtained from image diagnosis is used as a reference. During capacitor testing, the insulation characteristics are diagnosed using both direct and indirect methods. The voltage measured by a D-dot probe, the output waveform of the Marx generator in the primary source, and the radiation field waveform are analyzed to understand the flashover characteristics of the capacitor and to improve the reliability of the test results. The experimental results demonstrate that the peaking capacitor can operate stably at 3.0 MV. If flashover occurring on the dropping edge of the pulse is permitted, the operating voltage can be greater than 3.7 MV without significantly affecting the radiation field waveform. The analysis on the surface flashover morphology of the peaking capacitor reveals that the flashover mainly occurs at the dropping edge of the capacitor's waveform, indicating that the damage to the film is not serious. This research significantly increases the working voltage of coaxial peaking capacitors and contributes to the development of high-altitude EMP simulation technology.
同轴脉冲形成电容器是具有快前沿脉冲输出的高空电磁脉冲（EMP）模拟器中的关键部件。它在限制辐射场幅度和测试空间方面带来了重大的技术和工程挑战。本文介绍了一种绝缘性能得到改善的180 pF、3 MV同轴脉冲形成电容器的设计与测试。在绝缘设计中，延长了介质膜的长度以降低闪络路径上的背景电场。将图像诊断获得的电场阈值用作参考。在电容器测试期间，使用直接和间接方法诊断绝缘特性。分析由D-dot探头测量的电压、初级源中马克思发生器的输出波形以及辐射场波形，以了解电容器的闪络特性并提高测试结果的可靠性。实验结果表明，该脉冲形成电容器可在3.0 MV下稳定运行。如果允许在脉冲下降沿发生闪络，则工作电压可以大于3.7 MV，而不会显著影响辐射场波形。对脉冲形成电容器表面闪络形态的分析表明，闪络主要发生在电容器波形的下降沿，这表明膜的损伤并不严重。这项研究显著提高了同轴脉冲形成电容器的工作电压，并有助于高空EMP模拟技术的发展。
