Bifilar coil is one of the most applicable structures used for resistive-type superconducting fault current limiter. However, the turn-to-turn (longitudinal) insulation of the bifilar coil under lightning and switching impulse is rather different from the conventional pancake coil. The longitudinal insulation is characterized as the distributed circuit of the coil under high-frequency excitation, and the capacitance, inductance, and resistance parameters are solved by finite element model. The influence of those resistance, inductance and capacitance (RLC) parameters on the accuracy of the model is analyzed, and two samples of one bifilar pancake coil and two series connected bifilar coils are fabricated for high-frequency impulse voltage testing. The experimental results are consistent with the simulation results. The initial voltage distribution and impulse response of two samples are calculated under standard lightning impulse. In the initial voltage distribution calculation, the interturn channels of one bifilar coil and two series-connected bifilar coils are subjected to a maximum voltage of 1 and 0.5 times the lightning impulse voltage.

中文翻译：

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双股超导线圈高频脉冲建模及纵向绝缘分析

双线线圈是电阻式超导故障限流器最适用的结构之一。然而，双线线圈在雷击和开关冲击下的匝间（纵向）绝缘与传统的扁平线圈有很大不同。纵向绝缘表征为线圈在高频激励下的分布电路，电容、电感、电阻参数通过有限元模型求解。分析了这些电阻、电感和电容(RLC)参数对模型精度的影响，制作了1个双线扁平线圈和2个串联双线线圈两个样品进行高频冲击电压测试。实验结果与模拟结果一致。在标准雷电冲击下计算了两个样本的初始电压分布和冲击响应。在初始电压分布计算中，一个双线线圈和两个串联双线线圈的匝间通道承受的最大电压分别为雷电冲击电压的1倍和0.5倍。