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Analysis of Lightning Surge on Transmission Line by New Numerical Electromagnetic Field Computation Method

新的电磁场数值计算方法分析输电线路雷涌

基本信息

批准号：
10650292
负责人：
KATO Shohei
金额：
$ 2.11万
依托单位：
Toyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

Although only the linear phenomenon had been treated in the numerical electromagnetic field calculation method, we studied how to treat an electric discharge phenomenon and added the function to simulate nonlinear phenomenon to the simulator in this research. Since the impedance changes every moment by the nonlinear phenomenon, a system equation will need be changed for every simulation time step and there is a problem which the computation time increases greatly. We noted that electric discharge and lightning arrestor are limited to be a part of transmission line, and used the algorithm which sets the number of current variables in order automatically so that it becomes the minimum change at the time of creation of a system equation. Even when the nonlinear element existed in the transmission line, it held down to the increase in about 10% of calculation time by this algorithm, and it becomes possible to simulate lightning surge within allowable calculation time.Lightning which compri … More ses electric discharge phenomena complicated from streamers to leaders and the return stroke is also a nonlinear phenomenon. It is important how a model is created in lightning surge analysis. We examined two kinds of models, the first is made by the inductive element and the second is a plasma core surrounded by space *rges. The later model could be easily programmed in the electromagnetic field analysis method, and also clarified that tne surge impedance of lightning channel becomes about five hundreds ohm and a little higher than the conventional lightning channel impedance used in circuit simulator.We have studied two methods to compute parameters for the impulse voltage expressed by the double exponential functions under given front time and tail time. The first method is based on the Newton method and shows good convergence in several iterations over wide ratio of front time and tail time. The second method uses an acceleration factor to decrease the differences of time parameters which are given by the iteration process. We can determine a double exponential function under a millisecond by both methods. However, a short tail impulse needs more number of iterations than standard lightning impulse Less

虽然在电磁场数值计算方法中只处理了线性现象，但本研究对如何处理放电现象进行了研究，并在模拟器中添加了模拟非线性现象的功能。由于非线性现象，阻抗每时每刻都在变化，因此对于每个仿真时间步长，都需要改变系统方程，并且存在计算时间大大增加的问题。我们注意到，放电和避雷器被限制为传输线的一部分，并使用自动设置电流变量的数量的算法，以便在创建系统方程时使其变化最小。即使在输电线路存在非线性元件的情况下，该算法也能将计算时间的增加控制在10%左右，并能在允许的计算时间内模拟雷电冲击。 ...更多信息放电现象从流光到先导是复杂的，回击也是一种非线性现象。在雷电浪涌分析中，如何建立模型是一个重要问题。我们研究了两种模型，第一种是由电感元件构成的，第二种是由空间区域包围的等离子体核。该模型可方便地用电磁场分析方法进行编程，并阐明了雷电通道的浪涌阻抗约为500欧姆，略高于电路模拟器中常用的雷电通道阻抗。第一种方法是基于牛顿法的，在很宽的前、尾时间比下，多次迭代收敛性良好。第二种方法利用加速因子来减小迭代过程中时间参数的差异。这两种方法都可以在毫秒内确定双指数函数。然而，短尾脉冲比标准闪电脉冲需要更多的迭代次数