ANALYSIS OF LIGHTNING SURGE IN SUBSTATION BY NEW SORGE

该项目旨在开发瞬变电磁场传播程序(TEPCO)，该程序可以用矩量法分析输电线路中的浪涌现象。该方法处理雷电浪涌中典型的非线性现象--线性电阻和感应元件的闪络模型，以及雷电在同一时间范围内的时间响应。为了验证程序的正确性，我们在一个微型模型上通过实验研究了雷电浪涌如何进入变电站，并注意到了电力线电流、地线电流和龙门电流之间的关系。如果在地线和龙门之间插入400OMEGA电阻，变电站入口处电力线上的浪涌电流峰值不到无电阻时峰值的一半。电力线电流与地线电流方向相反。还研究了在双地线和三地线情况下，地线的倍增效应对防止反闪络的影响。在地线电流感应的原因中，三根地线的电力线电流比双根地线增加了15%。然而，弧间的电压以三倍的速度相反地减小。因此，地线倍增是防止反闪络的有效措施。由于相对几何关系对输电线路雷电冲击的影响，在分析输电线路雷电冲击进入变电站时，必须考虑线路与门架之间的相互耦合。

The project aimed to develop the Transient Electromagnetic Field Propagation Code (TEPCO) which can analyze surge phenomena in transmission lines by Moment Method. The method deals the time response in same time range, and linear resistance and inductive element flashover model which is a typical nonlinear phenomena in lightning surge. To verify the code, we studied how the lightning surge travels into a substation by experimentally in a miniature model taking notice of the relations between the power line currents, ground wire currents and gantry currents. If we insert the resistance 400OMEGA between ground wire and gantry, the surge current on the power lines at the entry of the substation shows the peak value less than a half of the peak in the resistance free. The power line current flows in the opposite direction with the ground wire current. It is also investigated the multiplication effects of ground wire to prevent back flashover in case of double and triple ground wires. In the cause of the induction by the ground wire current, the power line current in triple ground wires increases 15% greater than the double ground wires. However, the voltage between are hones in triple decreases contrariwise. Therefore, the multiplication of ground wire is effective for the avoidance of back flashover. As the relative geometrical relations influence the lightning surge on the power lines, it is necessary to account the mutual coupling between the power lines and gantry in the analysis of the surge traveling into a substation.