Chen Zhi-Qiang, Ji Sheng-Chang, Jia Wei, Zhu Xiang-Qin, Liang Tian-Xue, Guo Fan, He Xiao-Ping, Wu Wei
State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 West Xianning Rd., Xi'an 710049, China.
State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69 Branch 20, Xi'an 710024, China.
Rev Sci Instrum. 2019 Dec 1;90(12):124709. doi: 10.1063/1.5118790.
As one of the key components of an electromagnetic pulse simulator, the peaking capacitor is coaxially constructed with a laminate structure utilizing alternative thin metal rings and polymer film dielectrics, which is designed as a part of the antenna. This paper presents a coaxial film capacitor with a novel structure to improve its flashover performance. First, the relationship between the capacitance and the capacitor's structural parameters are deduced, and a theoretical basis of lengthening the polymer film dielectrics to enhance the flashover performance is discussed. Based on the theoretical analysis, two 150 pF, 3-layer coaxial film capacitors with different extended lengths for the polymer film dielectrics (10 and 60 mm) are designed and developed. For the capacitor with a 60 mm extended film dielectric, the polymethylmethacrylate rings are adhered to the thin metal rings to support the polymer film dielectrics using a soft adhesive. Electric field analyses show that a longer extended length could decrease the surface field at the edge of the polymer film dielectric by as much as 93%. Comparative insulation experiments show that the flashover voltage for the improved capacitor is 89.9% higher than the original one. The influence of the capacitor's polymer extensions (including the polymer supporting rings and the film dielectrics) on the radiating field of a cone antenna is analyzed numerically, and the results show that only slight changes are introduced into the radiating field. Finally, a designed 350 pF, 20-layer coaxial film capacitor with lengthened film dielectrics is presented.
作为电磁脉冲模拟器的关键部件之一，脉冲形成电容器采用交替的薄金属环和聚合物薄膜电介质以层压结构同轴构建，其被设计为天线的一部分。本文提出了一种具有新颖结构的同轴薄膜电容器以改善其闪络性能。首先，推导了电容与电容器结构参数之间的关系，并讨论了延长聚合物薄膜电介质以提高闪络性能的理论基础。基于理论分析，设计并研制了两个150 pF、3层的同轴薄膜电容器，其聚合物薄膜电介质的延长长度不同（10和60 mm）。对于聚合物薄膜电介质延长长度为60 mm的电容器，使用软粘合剂将聚甲基丙烯酸甲酯环粘附到薄金属环上以支撑聚合物薄膜电介质。电场分析表明，更长的延长长度可使聚合物薄膜电介质边缘处的表面电场降低多达93%。对比绝缘实验表明，改进后的电容器的闪络电压比原来的高89.9%。数值分析了电容器的聚合物延长部分（包括聚合物支撑环和薄膜电介质）对锥形天线辐射场的影响，结果表明辐射场仅引入了轻微变化。最后，给出了一种设计的具有延长薄膜电介质的350 pF、20层同轴薄膜电容器。
