一种高功率三平板传输线电压测量探头的设计

 为测量高功率水介质三平板传输线的电压，设计、标定了一种D-dot探头，安装在三平板线的入口和出口处，探头感应脉冲电压的微分信号。探头与基座之间的绝缘层为浇注的环氧树脂，可以在满足密封去离子水的要求下，使探头对地电容较小，从而获得良好的高频响应。利用ANSYS对探头结构进行了优化设计，使三相点位置的电场强度得到有效降低。使用经线下标定过的电阻分压器进行标定。实验中采用电容器放电，用一段高压电缆作为脉冲形成线获得逐级上升的快前沿（约70 ns）电压脉冲，并将之作为标定信号源，标定得到三平板线入口、出口探头的灵敏度分别为386 kV/V和402 kV/V。探头测量结果与电路模拟结果一致。在三平板线耐压实验中，板线出口电压达到了3.1 MV，探头的绝缘结构设计能够满足要求。实验结果表明该探头适合高功率三平板传输线电压的测量。

D-dot design for high-power triplate transmission line voltage measurement

Two D-dot monitors have been designed to measure the voltage pulse on a high-power triplate transmission line. One has been installed in the entrance and the other in the exit. A signal proportional to the time derivative of voltage is given from the D-dot monitor, and the voltage can be got by a passive RC integrator. Insulation of probe is achieved by epoxy, and dispersed capacitance between the probe and the ground can reduce by the designed waterproof configuration. Two-dimensional electrostatic simulations show that the amplitude of electric field at water-insulator-metal triple-point is low. These monitors are calibrated in-situ using a calibrated resistive divider and a pulser which produces high voltage with an HV cable as a forming line. The generated signal with steps and rise ti