作　　者： ; ; ;

机构地区： 清华大学

出　　处： 《中国电机工程学报》 2007年第36期8-13,共6页

摘　　要： 土壤结构模型决定了HVDC接地极极址选择、布置形式和地表电位的分布,对分析HVDC单极运行对变压器产生的影响有重要作用。该文利用土壤水平分层和垂直分层后的格林函数,通过镜像法,根据其物理意义推导出在复合分层土壤结构中地表电位的解析公式。海洋在面积上远大于陆地,电阻率很小,对地表电位有影响,会降低靠近海洋附近土壤的电位。根据复合土壤模型和交流电网模型计算得到变压器中性点流过的直流电流,和实测值相符合。靠近海洋层的地表电位受到海洋的影响将下降至接近零电位,导致更多的直流电流从靠近海洋的变压器中性点流出,影响了变压器的正常运行。 The soil model determines fundamental rule of site selection, HVDC ground electrode design and surface potential distribution. It is important to analyze the influence of HVDC monopolar operation with ground return on transformers. By means of deriving the Green＇s function in horizontal-layer and vertical-layer soil structures, the formula calculating potential for complex soil layer was derived using the concept of image. Sea area is larger and its resistivity is smaller than that of the land, so it reduces soil surface potential where is near the sea. The calculations of DC currents through the neutrals of transformers are matched to the measures, taking into account complex soil model and AC power grid. Simulation results show the surface potential closed to sea drops to zero influenced by sea. The lower potential of substation makes more DC currents of power grid flow through transformer neutrals and causes DC bias of transformers.

关 键 词： 电力系统 直流输电 土壤模型 接地极 电流分布

领　　域： [电气工程]