负荷对冲击电压发生器输出能力的影响研究

冲击电压试验中,GIS和高压电缆试品的负载电容可达3 000 pF至10 000 pF。为满足这种大负荷试品的冲击试验输出波形要求,对设计中未考虑大电容试品的常规发生器,需要通过改造提高其输出能力。以15级的3 000 kV冲击电压发生器为例,应用ATP暂态电磁仿真软件建立发生器模型,对在发生器输出端串入高压阻容元件这种改进电路方法进行仿真。定量分析了发生器负载、总电感和等效波头电阻对输出波形的影响,以及输出效率随负载的变化。大负载情况下应用这种改进措施后,发生器的负载能力可从4 000 pF提高到11 000 pF,波形过冲可控制在10%以内。对于高压引线的长度限制也给出了建议。

Investigation of Load Impact on Output Capability of Impulse Voltage Generators

The entrance capacitances of GIS and HV cable can reach 3 000 pF to 10 000 pF in impulse voltage test.It is necessary to improve the output capability of the impulse voltage generators(IVG) which were designed without consideration of large capacitance loads.In this paper,by applying the ATP simulation method,a 15-stage 3 000 kV IVG with a high-voltage RC-filter at the output terminal for improving output capability is analyzed.The waveform influencing factors including load,total inductance,and equivalent resistance,and the output efficiency are investigated.It is shown that the above improving method can enhance the IVG output capability from 4 000 pF to 11 000 pF,with the waveform overshoot being controlled within 10%.In addition,the length limit of HV connecting wire is suggested.