中文摘要：

雷击接地网或者发生短路故障时，变电站接地网导体上的电流以及土壤中的泄漏电流会产生较强的空间磁场，可能影响站内设备的正常工作进而危害变电站的安全运行，计算接地网常用的矩量法无法考虑土壤中的泄漏电流对空间磁场的影响。为此，基于矩量法提出了一种计算土壤中泄漏电流所产生的磁场的方法。利用矩量法求得的接地网导体上的泄漏电流可以计算土壤中任意位置的电场强度，进而求出该位置土壤中的泄漏电流密度。接地网周围土壤区域的泄漏电流所产生的磁场与地网导体轴向电流所产生的磁场之和即为实际接地网所产生的磁场。研究结果表明，采用该方法进行空间磁场计算不仅可以克服传统矩量法的缺点，而且计算速度明显优于同样可以考虑土壤泄漏电流的有限元方法。通过与有限元方法进行比较验证了该方法的有效性。

英文摘要：

The safety of substation may be affected by the magnetic field generated by the currents on the metal conductors of the grounding grids and the leak currents in the soil around the grids when a fault occurs. Consequently, a fast method is developed to analyze the leak currents in the soil based on the moment method. As the electric field intensity at any position in the ground can be calculated using the leak currents on the conductors of the grids obtained by the moment method, the leak currents density in the soil can be obtained. The magnetic filed generated by the grounding grids can be treated as the sum of the magnetic field induced by the currents on the conductors and in the soil around the grids. This method can be faster than the finite element method. Compared with the finite element method, the present method is proved to be correct and effective.