中文摘要：

地磁感应电流（geomagnetically induced currents,GIC）引起变压器半波饱和对电力系统的安全运行产生不利影响,甚至引发大面积停电事故。为了有效治理GIC对大规模电力系统的不良影响,提出变压器中性点配置小电阻器减轻电网GIC的解决思路,同时结合甘肃省750/330kV电网GIC相互作用及中低纬地区地磁暴的特点,给出10种不同的组合治理方案。制定了评价电网GIC水平的4个指标,并对上述10种方案的治理效果进行了评估。结果表明750/330k V双电压等级电网GIC治理难度较大,特别是GIC高风险节点的抑制,配置不当会使治理效果恶化,同时,750kV变电站中性点配置小电阻器抑制GIC较330kV变电站的作用大,且在电网末端750kV变电站配置小电阻器抑制电网GIC的效果较明显,可使GIC的最大值降低30%。研究结果希望为电网GIC治理提供理论基础和技术支撑。

英文摘要：

Geomagnetically induced currents（GIC） can cause half cycle saturation of transformers and adversely affect secure operation of power system, even resulting in large scale blackouts. To effectively mitigate GIC negative impacts in large-scale power system, a method is proposed to reduce power network GIC by placing small resistors in grounding neutral-point of transformers. Meanwhile, ten different configurations are presented for mitigating GIC considering characteristics of GIC interaction between 750kV and 330kV power grid in Gansu Province, China and geomagnetic storm in middle-low latitude regions. Four evaluation indexes used to assess GIC level are defined and ten above-mentioned configurations are evaluated. Result indicates difficulty of mitigating GIC in a 750kV/330kV dual voltage level power grid, especially for nodes with large GIC values. If configuration is unsuitable, effect of GIC mitigating measures could be adverse. GIC mitigation effect is better at 750kV substation than that at 330kV substation, and maximum GIC is reduced by 30% when the small resistors are placed in 750kV substations at power grid terminal. Research in this paper will provide support and basis for future researches in GIC mitigation in power grid.