特快速暂态过电压(Very fast transient overvoltage,VFTO)对电力设备的稳定安全运行造成了严重危害,因此对VFTO进行准确测量具有重要意义。针对目前应用较为广泛的基于耦合电容法的VFTO传感器,本文设计的2 kV方波标定平台采用同轴传输腔体结构用以模拟GIS母线筒,并通过仿真研究探索了不同腔体结构参数对方波标定平台传输特性的影响,给出了结构优化方案。仿真结果表明,同轴传输腔体主段内导体外半径为44.75 mm,外导体内半径为10 mm时,同轴传输腔体的波阻抗为50 Ω；内导体绝缘支撑采用三支柱支撑方式,并且在窗口直径设置为57.5 mm,过渡段长度400mm,末端匹配筒为指数型且长度为30 mm时,该方波发生器具有较好的传输性能。结合仿真研究结果搭建方波标定平台,输出幅值>2kV,上升沿<1ns,满足VFTO传感器标定要求。
英文摘要:
VFTO (Very fast transient overvoltage) has caused serious damage to the stable and safe operation of power equipment. Therefore, accurate measurement of VFTO is of great significance. Aiming at the widely used VFTO sensor based on coupling capacitance method, the 2kV square wave calibration platform designed in this paper useing coaxial transmission cavity structure to simulate GIS busbar. The effects of different cavity structure parameters on the transmission characteristics of the square wave calibration platform are explored by simulation research, and the structure optimization scheme is given. The simulation results show that when the outer diameter of the inner conductor of the coaxial transmission cavity is 43.46 mm and the inner diameter of the outer conductor is 100 mm, the wave impedance of the coaxial transmission cavity is 50 Ω. The inner conductor insulation support shall adopt the three-pillar support mode, and the square wave source has better transmission performance when the window radius is set to 57.5 mm, the transition section length is 380 mm, and the end matching cylinder is exponential with the length of 30 mm. Combined with the results of simulation research, the square wave calibration platform is built. The output amplitude is >2kV and the rising edge is <1ns, which meets the calibration requirements of VFTO sensor.