中文摘要：

地磁扰动（geomagnetic disturbances,GMD）下的特高压直流输电（ultra high voltage DC,UHVDC）系统,送受端交流电网的地磁感应电流（geomagnetically induced current,GIC）会侵入UHVDC换流变压器,导致其直流偏磁及产生谐波和温升等次生干扰。为研究地电场方向和接入系统结构对换流变GIC的影响,针对规划的蒙西换流站的2个接入系统方案,提出建模计算以15？为间隔的24个不同方向感应地电场作用下换流变GIC,并评估了2004年11月9日强磁暴作用下的GIC。结果表明,强磁暴产生的GIC会引起换流变严重的直流偏磁,同一地电场作用下2种接入系统方案中换流变GIC值差别较大,地电场方向对换流变的GIC也有较大影响。

英文摘要：

For ultra-high voltage direct current（UHVDC） power transmission system during geomagnetic disturbances（GMD）,geomagnetically induced currents（GICs） generated in sending and receiving AC systems will flow into convertor transformers in UHVDC system and cause DC-bias of convertor transformers,leading to a number of undesirable effects,such as harmonic generation and transformer heating.In order to analyze impact of geoelectric field direction and connected AC system structure on GICs in convertor transformers,this paper took planned Mengxi convertor station and its two programs of AC system connection as example,established a model to calculate GIC in convertor transformers under 24 electric fields with different directions with 15° interval,and assessed GIC under strong storms in 9-10 November 2004.Analysis shows that GICs driven by strong storms cause serious DC-bias of convertor transformers,and GIC amplitudes of these two programs are quite different for the same electric field,and electric field direction has obvious impact on GIC in convertor transformers.