雷击终端场时电缆金属护套过电压及其影响因素研究

The Research on Lightning Overvoltage of Cable Sheath and Its Influencing Factors in Cable Terminal Field

为了研究雷击终端场时电缆金属护套过电压,基于ATP-EMTP电磁暂态计算软件建立110kV终端场过电压计算仿真模型,对雷击杆塔和绕击线路两种工况进行研究,并讨论了金属护套过电压的影响因素。研究结果表明:雷击杆塔时相比绕击时金属护套的过电压更大,但震荡时间更短;线路越长绕击的过电压越大,而雷击杆塔的过电压相反;电缆分段不均匀会增大过电压;接地电阻对绕击的影响更大;大地电阻率对过电压基本无影响。

In order to study the lightning overvoltage of the cable sheath in cable terminal field,Asimulation model of overvoltage about 110 kV cable terminal field is established based on ATP-EMTP,an electromagnetic transient calculation software.Two working conditions of the lightning tower and shielding failure are studied,and the influence of influencing factors on the overvoltage of cable sheath are discussed.The results show that the overvoltage of the cable sheath when the lightning tower is larger than that when shielding failure,but its oscillation time is shorter.Besides, when shielding failure,the longer the line is,the greater the overvoltage is,while it is contrary when lightning tower, and non-uniform cable segments will increase the overvoltage.The grounding resistance has greater impact when shielding failure,and the earth resistivity has little effect on the overvoltage.