智能电表雷电感应过电压防护分析

Protection Analysis of Smart Meters Against Lightning Induced Overvoltage

智能电表的广泛应用伴随着严重的雷电灾害威胁,需要对智能电表雷电感应过电压防护进行详细分析。利用ATP软件搭建配电系统模型,编程计算线路雷电感应过电压,分析雷击点距线路距离和回击速度对智能电表终端过电压的影响,讨论安装线路避雷器、变压器低压侧避雷器、末端SPD的防护效果。分析结果表明:10 kV线路附近发生雷击时,感应过电压传递至智能电表终端时幅值仍然较高,50 kA雷电流幅值下终端过电压超过IV类设备冲击耐受电压;智能电表终端过电压随着雷击点距线路垂直距离的增加、回击速度的减小而降低;输电线路避雷器安装密度会影响智能电表终端过电压幅值出现概率,避雷器安装越密,幅值较低的过电压出现概率越高;变压器低压侧避雷器能够有效抑制智能电表终端过电压,但抑制效果受变压器与智能电表间连接线路长度影响,线路越长,过电压抑制效果越差。为实现更加精细的智能电表过电压防护,可以在智能电表前面安装末端SPD。

The wide use of smart meter goes with severe lightning disasters,so it is necessary to study protection of smart meters against lightning induced overvoltage. A model of the distribution system was established in ATP-EMTP and lightning induced overvoltage was calculated by means of programming. Influence of distance from lightning strike point to the distribution line and current wave propagation speed on overvoltage of the smart meter were discussed. Protection effect of arresters and SPD was presented.Simulation results show that： transferred overvoltage due to lighting induction from 10 kV line remains high which exceeds impulse withstand voltage of class IV distribution equipment at 50 kA lightning current amplitude. Overvoltage decreases with the increasing of vertical distance from lightning strike point to the distribution line as well as the decreasing of current wave propagation speed. Probability of lightning overvoltage of the smart meter exceeding the corresponding value is affected by installation density of line arresters. Protection effect of the low voltage arrester decreases with the increasing of 220 V line length.Overvoltage of the smart meter can be inhibited significantly when the terminal SPD is installed.