基于1989年3月地磁暴的蒙东电网事故风险评估

Risk Assessment of East Inner Mongolia Power Grid Accident Based on Geomagnetic Storm in March 1989

随着电网技术发展,大电网导线的截面越来越大,包括500 kV线路开始采用630 mm24分裂或6分裂导线,相同强度大地磁暴发生电网事故的风险越来越大。针对以前利用2004年11月9日地磁暴数据评估电网风险存在的不足,利用中国地震局地球物理研究所提供的数字化的1989年3月13日地磁暴数据,以及吉林大学地球探测科学与技术学院提供的大地电磁测深的数据资料,建立了蒙东地区地磁暴地电场模型和电网地磁感应电流(geomagneticallyinduced current,GIC)电路模型,提出了评估电网地磁暴事故的评价指标,完成了蒙东220 kV及以上电压等级电网变压器中性点GIC和变压器GIC无功(GIC-Q)扰动的理论计算。结果表明,由于蒙东电网在我国地处磁纬相对高、线路的长度相对长和一些新建电网导线的截面相对大,与1989年3月13日地磁暴诱发的加拿大魁北克400 mm24分裂735 kV电网大停电事故相比,蒙东500 kV电网也存在地磁暴事故的高风险,防治地磁暴事故已成电网建设的重要任务。

With the development of power grid technology,the cross-section of large power grid conductors is getting larger and larger,including 630 mm^2 four-split or six-split conductors used on 500 kV lines,which may leads to a high risk of grid accidents with the same intensity of large-scale magnetic storms.To overcome the shortcomings of the evaluation of the risk of power grids with the geomagnetic storm data on November 9,2004,the digital geomagnetic storm data of March 13,1989 provided by the Institute of Geophysics of the China Earthquake Administration are adopted.With these data and the ones of the electromagnetic sounding in the earth offered by the School of Earth Exploration Science and Technology of Jilin University,this paper establishes a model of the geomagnetic storm geoelectric field and the geomagnetically induced current(GIC)circuit model in the East Inner-Mongolian area.It proposes the evaluation index for assessing the geomagnetic storm accident of the grid,and completes the theoretical calculation of the neutral point GIC and transformer GIC reactive power(GIC-Q)disturbances of 220 kV and above voltage grids in this area.The results show that the East Inn-Mongolian grid lies in the relatively higher magnetic latitude,and there are longer power lines and larger cross sections of the conductors in some new power grids.Compared with the l2 arge-scale power outage accident in the 735 kV grid in Quebec,Canada,which induced a major geomagnetic storm on March 13,1989,the 500 kV power grid in East Inner-Mongolia,China also has a high risk of geomagnetic storm accidents.The control and prevention of the geomagnetic storm accidents has become an important task in the power grid construction.