摘要
针对目前直流接地极选址存在的困难,提出广域接地极的新方案,即通过特定的形式把某一区域内的直流接地极连接起来,形成一个大型的散流体作为直流接地极。以广东电网公司应用该方法的实例证明该方案具有显著的经济性和较高的操作性,并且在技术上有明显优势,能够降低接地电阻,缓解直流输电单极大地运行对交流电网的不利影响,但存在入地电流局部集中的现象。通过进一步分析,提出改进方法,即利用局部串阻和改变入地电流接入点,可改善电流在广域接地极的分布,而实践证明改变接入点的技术性和可靠性更高。通过对广域接地极对后续直流工程的适应性分析,得出结论:广域接地极作为一种创新的设计理念,可通过一系列技术措施的实施及改进,缓解直流落点增多与接地极选址困难的矛盾。
For the difficulty in siting of DC grounding electrode,the new idea of wide-area grounding electrode is presented.By special connection way,grounding electrodes in some area become a large scattering electrode.The example of Guangdong Power Grid Corporation using the method verifies its great economic efficiency and operability.It has obvious technical advantages,able to decrease the grounding resistance and the side-effect of HVDC mono-polar ground operation on AC power network.However,there also exists local concentration of earth current.Improving methods are proposed upon further analysis,in which local series resistance is utilized and earth current injection point is changed to improve the current distribution in wide-area grounding electrode.It is testified in practice that changing current injection point is of higher technical feasibility and reliability.Upon analyzing the adaptability of wide-area grounding electrode to subsequent DC project,it is concluded that as an innovative design idea,wide-area grounding electrode can,through the implementation and improvement of a series of technical measures,ease the contradiction between increasing number of HVDC transmission projects and siting difficulty of grounding electrodes.
出处
《广东电力》
2010年第11期67-72,共6页
Guangdong Electric Power
关键词
直流输电
直流接地极
中性点直流
直流偏磁
HVDC transmission
DC grounding electrode
neutral direct current
DC bias
