磁暴期间技术系统感应电压的计算

Calculation of the Induced Voltages in Technological Systems During Geomagnetic Storms

磁暴期间,导电网络(如电力系统、管道和电话电缆)中会感应出电压。用计算穿过环路的变化垂直磁场或者计算由沿环路变化的水平磁场来得到地面水平环路感应出的电压,这两种方法是等效的,都应用了麦克斯韦方程组,但是它们的等效很难形象化地给予解释。考虑到磁场的发散特性,穿过水平环路的垂直磁场如何相关到环路外围的水平磁场(由于地面线电流),用磁扰动的例子来说明两种方法在计算导电网络中感应电压上是等效的。

During geomagnetic storms, voltages can be found induced in electrically conducting networks such as power systems, pipelines, and phone cables. The voltages produced in a horizontal loop at the earth＇s surface can be calculated by considering the changing vertical magnetic field through the loop or by calculating the electric field around the loop from the horizontal magnetic field variations. The two approaches are equivalent, both being a consequence of Maxwell＇s equations, however, it is not easy to visualize this equivalence. On account of nondivergent nature of the magnetic field, it is shown how the vertical magnetic field through a horizontal loop is related to the horizontal magnetic field at the periphery of the loop. The case of a magnetic disturbance due to a line current above the earth＇s surface is used to illustrate the equivalence of the two approaches for calculating the voltage induced in a conducting network.