两次磁暴期间广东电网地磁感应电流的分析

Analysis of geomagnetically induced currents generated in guangdong power grid during two magnetic storms

地磁感应电流(Geomagnetically Induced Current, GIC)会对低纬和赤道地区高压电网安全运行构成威胁.本文利用广东肇庆地磁台在2006年12月14-15日,2015年3月17日两个磁暴发生期间监测到的地磁场数据,研究和计算了广东500 kV电网两条输电线路上由地磁暴激发的GIC,并利用NASA Space Physics Data Facility网站提供的太阳风和行星际磁场数据分析了该区电离层赤道电急流(Equatorial Electrojet, EEJ).结果显示:广东500 kV电网输电线路易受地磁暴引发的GIC干扰.GIC除和输电线路的长度、线路所处的地貌特征、沿海输电线路遭受到的海岸效应有关外,赤道电急流在GIC的激发方面起着重要的作用.赤道电急流对GIC的影响发生在地磁暴的急始期,也发生于地磁暴的主相期,和行星际磁场B_z在太阳风动压增加时产生的南向偏转有关.

The operation of power grid infrastructures in the low latitude and equatorial regions are susceptible to the threat from Geomagnetically Induced Current(GIC). In this paper, the magnetometer data collected from geomagnetic station at Zhaoqing, Guangdong were analyzed to investigate the GICs caused in two transmission lines of Guangdong 500 kV power grids during two geomagnetic storms of 14-15 December 2006 and 17 March 2015. The Equatorial Electrojet(EEJ) was also investigated using data from NASA Space Physics Data Facility Network. We have found that Guangdong 500 kV power grid infrastructures were susceptible to the GIC induced by two geomagnetic storms. And the EEJ played a significant role in inducing GIC. The level of GIC is also associated with the length of transmission line, the topographical features and the shore effect of the coastal transmission line. The effects of EEJ on GIC occurred at the Storm Sudden Commencement(SSC) or during the main phase of the storm which is associated with the southward turning of Interplanetary Magnetic Field(IMF) B_z due to the increases of the solar wind dynamic pressure.