时变激励下接地网模拟计算

Numerical Calculation of Substation Grounding Systems in Time-Varying Field

接地网模拟计算对工程接地网设计有着重要的指导作用。接地阻抗、接触电压、跨步电压是接地网设计的重要指标, 根据这些接地网参数来判断接地网设计的合理性。时变激励下的接地网模拟计算能够较为准确地求得接地网上的电压分布, 从而进行变电站内电子设备之间的电磁干扰分析。基于时变场中电流元在分层媒质中产生的电磁场问题的研究, 利用接地网导体棒表面沿轴向电场强度分量连续的边界条件, 列写了以各段导体棒电流为未知量的方程组, 从而求得各段导体电流, 进而得到各接地网参量以及接地网电压分布。采用该方法编制的一套软件可以得到接地网的接触电压、跨步电压、接地阻抗及其频率特性、接地网各点和接地网周围各点电压, 在计算效率和计算精度上能够满足实际工程设计的需要。

Grounding impedance, contact voltage and peace voltage are very important parameters for identifying rationality of the grounding design. Getting the potential distribution of grounding grids accurately in time-varying field, the analysis of electromagnetic interference may be analyzed. Based on the result of the research about the electromagnetic field generated by current element in layered medium, the equations for calculating the current values of the conductor segments may be got by using the boundary conductions for tangential component of the electric field at the surface of the conductor segment. The parameters and the potential distribution and the potential distribution of grounding grids are obtained.