中文摘要：

地磁感应电流（geomagnetically induced currents,GICs）流入高压变压器会造成其铁心产生半波偏磁饱和,吸收的无功增加,导致整个电网的无功波动与电压降低,可能威胁电网的安全运行。以甘肃750 k V电网和330 k V电网GIC的计算数据为基础,基于变压器GIC无功（GIC-Q）损耗系数K值算法,计算了750 k V和330 k V变压器的GIC无功损耗增量;在此基础上,利用电力系统综合分析程序和考虑全网GIC-Q同时增大、不同运行方式等因素的影响,采用牛顿法计算了甘肃750 kV电网和330 kV电网各节点GIC-Q波动的量值及其电压水平的指标;最后,研究了GIC-Q波动对750 kV电网和330 kV电网的节点电压的影响,以及两个电压等级电网之间GIC-Q和电压波动的相互影响。结果表明：整体上750 kV和330 kV电网节点GIC-Q和电压的波动不是非常大;与普通节点相比,750 kV终端变电站节点的GIC-Q和电压的波动相对大,是GIC侵害致灾风险相对高的站点。

英文摘要：

Geomagnetically induced currents（GICs） in power systems generated during magnetic storms can lead to severe half-cycle saturation and increase reactive power consumption in transformers, causing subsequent reactive power fluctuation and voltage drop and thus threatening safe operation of power systems. Based on GIC data of 750 k V and 330 k V power networks in Gansu province in China, the paper calculated transformers＇ GIC-Q increment according to transformers＇ reactive loss coefficient K. Then Newton method and Power System Analysis Software Package 7.1 was used to calculate GIC-Q fluctuation and voltage level of 750 k V and 330 k V grids. Influence of different operation modes and simultaneity of GIC-Q loss increase were considered in the process. At last, impact of GIC-Q fluctuation on 750 k V and 330 k V grids was analyzed. Mutual influence between these two power grids was investigated. Results showed that GIC-Q and voltage fluctuation of 750 k V and 330 k V grid nodes were not salient overall; but GIC-Q disturbance and voltage fluctuation in 750 k V nodes of terminal substations were relatively larger than that in ordinary nodes, making them more vulnerable to GIC encroachment.