磁暴期间中低纬度地区地磁场变化率的规律

Variation Rate Characteristics of Mid-to-low Latitude Area Geomagnetic Field During Geomagnetic Storms

磁暴期间的地磁场将会发生剧烈变化,根据法拉第电磁感应定律,地磁场的变化将在电网中产生地磁感应电流(GIC),这将直接损伤电力设备,威胁电网的运行安全。地磁场变化越剧烈,感应产生的GIC幅度越大,对电网的危害就越大。利用中低纬地区若干地磁台测得近年发生的两次大磁暴的H和D分量秒数据,分析了当地磁场变化非常剧烈时,对应的地磁南北分量变化率dX/dt脉冲幅值和地磁东西分量变化率dY/dt脉冲幅值随地磁纬度的变化规律,讨论了中低纬度地区不同走向的电网随着地磁纬度的变化受GIC影响的可能性,分析结果为中国现状电网及规划电网GIC评估、计算、防治提供了一定科学参考。

The geomagnetic field changes acutely during geomagnetic storms. According to Faraday＇s law of the electromagnetic induction, the change of the geomagnetic field produces a geomagnetically induced current in the power grid, which directly damages the power equipment and threatens the safe operation of the power grid. The more dramatically geomagnetic field changes, the bigger geomagnetically induced current in the power grid becomes, and thus, the greater harm to the power grid. In this paper, based on the H and D components of the recent geomagnetic storm data measured by several mid-to-low latitude geomagnetic observatories, the variation law of the amplitude of north-south and east-west geomagnetic component change rate （dX/dt and dY/dt） pulses with geomagnetic latitude is analyzed when the geomagnetic field changes very severely. Finally, the possibilities of the power grid in different directions being affected by GIC with the change of latitude are discussed. The analysis results will contribute to the evaluation, the measurement and the control of GIC in the current and future power grids in China,