【摘要】 为研究短尾波下空气间隙的放电特征,通过PSCAD/EMTDC仿真了雷击过程中绝缘子串电压的仿真波形,发现仿真波形与标准双指数波在上升时间和波尾时间上均有较大差异。通过改装冲击电压发生器,得到了与实际作用在绝缘子两端的电压波形比较接近的短尾冲击电压波。0.5～1.4m长棒板空气间隙在短尾波作用下放电特性的试验及数据分析表明:其放电电压显著高于标准波作用下的对应值,正极性冲击放电电压差别可达40%。最后分析了先导模型参数对结果的影响,利用实验结果结合先导发展判据,计算了适用于短尾波仿真的先导发展参数。更多还原

【Abstract】 To investigate the overvoltage during direct lightning strike,models on PSCAD/EMTDC platform were designed to simulate the transients during lightning direct strike on transmission tower and impulse voltage waves imposed on insulators According to the simulation results,the actual impulse voltage is not same as standard one.And the differences may cause errors in the evaluation of lightning performance.The breakdown characteristics of air gap under short-tail impulse,which is similar to actual waveform,were experimentally investigated.In the experiment,the impulse wave featured a reduced wave-tail time which was less than 10μs.It would cause equivalent effects to the air-gap with actual lightning strike.The air gap under study was a rod-plane gap with the length ranging from 0.5 ～ 1.4 m.The experimental result indicates that the breakdown voltage of air gap under short tail impulse is significantly higher than that of standard wave,about 40% higher for positive impulses,implying that previously-used methods may yield much lower withstand lightning current and consequently causes an over-investment on insulation.Finally,the parameters of Leader Propagation Model were studied and their effects on the simulation results were illustrated.Experimental data shows that the LPM can be applied to calculate the breakdown characteristics of short-tail waveform with good accuracy,and a set of parameter suitable for short-tail impulse is acquired.更多还原