一种10kV方波电压发生器

High Voltage Square Wave Generator

为了对高电压分压器进行实验标定,研制了一台最高输出电压为10 kV的方波发生器。它由直流高压源、脉冲形成线、高气压气体火花开关和脉冲传输线构成,以波阻抗为50Ω的聚乙烯高频同轴电缆作为脉冲形成线和脉冲传输线,并采用紧凑型氮气火花开关,改变脉冲形成线的长度和开关的气压可分别改变方波脉宽和幅值（3-10 kV）。实验中脉冲形成线的长度为10 m,对应的方波脉宽为100 ns。开关中氮气为0.2-0.7 MPa时,输出方波前沿的上升时间为14.1-1.5 ns,随气压的上升而急剧下降,且上升时间和气压的关系式不同于由J.C.Mar-tin公式推导的结果。0.7 MPa时间隙静态击穿场强高达500 kV/cm,为输出方波上升时间大大减小的根本原因。由上述实验知：该方波发生器完全适合于高电压分压器的实验标定。

In order to calibrate high voltage dividers, a square wave generator was constructed and its maximum output voltage was 10 kV. The generator consisted of a DC high voltage source, a pulse forming line （PFL）, a spark switch filled with pressurized nitrogen and a pulse transmission line （ PTL）. Both PFL and PTL were made from the cables with wave impedance of 50 Ω. The length of the PFL was 10 m, corresponding to a pulse width of 100 ns. The spark switch was made as compact as possible to reduce inductance. The pulse amplitude varying from 3 kV to 10 kV could be easily obtained by changing the nitrogen pressure. The rise time of square wave from the generator was in the range of 14.1 ns to 1.5 ns when the nitrogen pressure filled in the spark gap varied from 0.2 MPa to 0. 7 MPa. It is found that the dependence of rise time on gas pressure is different from that derived by the famous J. C. Martin formula. The 0.4mm gap filled with pressurized nitrogen of 0.7 MPa is broken down at an electric field as high as 500 kV/cm, making the rise time much decreased. The experimental results show that the generator is quite suitable for the calibration of high voltage dividers.