改善直流电流地中分布的接地极互联技术研究

发布时间：2018-08-09 09:33

【摘要】：直流接地极入地电流会造成附近交流电网变压器偏磁、埋地管道腐蚀等问题,成为直流接地极建设、直流系统运行中的难题之一。将已有临近接地极互联是减小直流接地极入地电流影响的措施之一。文章以南方电网在广东地区的4个已有接地极为例,通过考虑接地极之间地中恒流场的影响,以及地上联络线的等效电路,建立场路耦合计算模型,研究不同接地极连接方式下各接地极的电流分配、地电位升等,由此提出一种通过专设集中汇流点将所有换流站的入地电流汇集在一起,再分配到各接地极,通过优化选择汇流点与各接地极联络线的导线调节电流分配的接地极连接方案。对比分析表明,该方案不但减少了直流系统对交流电网变压器、埋地管线等设施的影响,而且今后的新建直流工程可以直接接入,无须再新建直流接地极,具有可靠、灵活、扩展容易、性价比高的特点。
[Abstract]:DC earth-pole earth current will cause magnetic bias of transformer and corrosion of buried pipeline, which becomes one of the difficult problems in the construction of DC earth pole and operation of DC system. It is one of the measures to reduce the influence of DC earth current to connect the adjacent earth poles. Taking the four ground poles of Southern Power Grid in Guangdong as an example, the field coupling calculation model is established by considering the influence of the constant flow field between the earth poles and the equivalent circuit of the above ground tie line. In this paper, the current distribution and ground potential rise of each earth pole under different connection modes of earth pole are studied, and a new method is proposed to collect the incoming current of all converter stations and distribute it to each ground pole by means of a special centralized confluence point. By optimizing the connection scheme of the current distribution between the confluence point and the connection line of each earth pole, the distribution of current is adjusted. The comparison and analysis show that this scheme not only reduces the influence of DC system on AC power network transformer, buried pipeline and other facilities, but also can be directly connected to the new DC project in the future, so it is reliable and flexible. Easy to expand, high cost-performance features.
【作者单位】：南方电网超高压输电公司检修试验中心;清华大学电机工程与应用电子技术系;
【分类号】：TM721.1;TM862

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