A Basic Study of New Design Method for Higher Lightning Protection Performance in Electrical Apparatus

在计算机网络系统中，由多根线组成的双绞线传输线被广泛用作数据通信信号线。采用电磁场数值计算方法矩量法研究了双绞线单相电力线的浪涌特性。频谱分析通常需要大量的计算时间，但该方法具有易于对双绞线等复杂结构建模的优点，本文研究了利用矩量法分析风力发电系统电力电缆和控制电缆系统中浪涌的电缆模型。作为应用，研究了电缆接地方式对过电压的影响，明确了降低过电压的接地方式。在降低过电压的有效接地电极的浪涌特性方面，通过与实验结果和仿真结果的比较，明确了矩量法和时域有限差分法各自的特点。采用矩量法和时域有限差分法（FDTD）对Transformer的铁心进行了仿真，考虑了铁心的等效模型，分析了铁心磁导率与铁心电阻率的关系，从趋肤深度到块状模型和层状模型，得到了导电率和层合数。为了验证仿真模型的正确性，采用冷轧硅钢片进行了实验，仿真结果与实验结果吻合较好

Twisted pair transmission line composed of several lines is used widely as data communication signal lines in computer network system. We used the Method of Moments (MoM), which is a numerical electromagnetic field computation method, to study the surge characteristics of twisted pair single phase electric power line. In generally large computing time is required for the frequency spectrum, but the method has an advantage that it is easy to model complex structures such as twisted pair.The cable model was studied to analyze the surge which arises in power cable and control cable system of wind power generation system by MoM. As the application, the overvoltages depending on the grounding method of the cable was examined, and grounding method which reduced the overvoltage was clarified.In respect of the surge characteristic of the effective grounding electrodes for the reduction in the overvoltage, it was shown that it clarified features of each analysis method, MoM and FDTD, in comparison with experimental results and simulation ones,and that we can apply them to the electrode design.The simulation model of iron core used to analyze surge characteristic of the transformer using moment method and FDTD method was examined.Equivalent core model is considered, and the relationship between the core permeability, conductivity and the number of lamination is obtained from skin depth to the massive model and the laminated one. In order to verify the simulation model, the experiment using cold rolling silicon sheet was carried out, and the simulation result and experimental result shows good accordance