配电线路-变压器系统对强电磁脉冲的电压响应

电磁脉冲易于耦合进入未经加固的架空线缆系统,对接入电子系统具有很强的干扰和破坏作用。为评估其特性和规律,基于Agrawal传输线模型对电磁脉冲作用下配电线路-变压器系统的感应电压进行数值模拟,得到线缆末端感应电压对电缆长度、高度和地表面参数的计算结果;将线缆感应电压作用到10/0.4 kV变压器上,计算了3类10/0.4 kV变压器低压绕组上的感应电压。数值模拟结果表明,配电线路接入未带负载变压器时,波形形状不变,仅电压峰值减小2/3;变压器接入负载时,电压峰值进一步减小1/3,峰时后延,脉宽减小,波形震荡明显减弱以至快速消失。该仿真结果,可用于指导电磁脉冲防护器件的选择,在防护效能的评估上也具有重要意义。

Induced Voltage Response Characteristic of Power-line Transformer System against Electromagnetic Pulse

The electromagnetic impulse is easily coupled into unreinforced overhead transmission line,which brings strong interference and damage to the connected electronic systems.According to the Agrawal transmission line model,the induced voltage of power-line transformer system is simulated,and the relationship among voltage,the cable's length and height at different ground conditions is analyzed.When the results are applied to a 10/0.4kV transformer,the induced voltage of transformer's low voltage side is worked out.The results indicate that the waveform does not change,when the electric power line is connected to unloaded transformer,only the peak value decreases by 2/3;When the transformer loaded,the voltage peak value further decreases by 1/3,the time of the peak is delayed,the pulse width is also minished,and the fluctuation of waveform is dramatically weakened to vanish swiftly.The simulation results can be used to direct the choice of protective devices and are of great significance in the evaluation of the shielding effectiveness.