多直流单极运行下的偏磁直流分布关键站点辨识方法

随着我国±1100kV特高压直流输电工程的建设,新疆电网在多个直流接地极共同影响下的直流偏磁风险也成为了电力部门需要解决的新问题。基于复杂网络理论,提出了多接地极共同作用下的偏磁直流关键站点辨识方法,研究了多接地极下偏磁直流站点间、站点与线路间的偏磁直流影响作用,提出了考虑影响因素不确定下的对偏磁直流分布有重要影响作用的关键度指标,以衡量多接地极作用特征最后,并给出了计算方法,以新疆750kV特高压交流系统为例,分析了在±1100kV准东特高压直流和±800kV天中直流共同作用下的影响偏磁直流分布的关键站点,与2018年10月期间实际测试数据对比,结果验证了方法的可行性和关键站点判据的有效性。论文研究成果可有效辨识对偏磁分布起到关键作用的变电站特征,为提高电网变压器直流偏磁的早期预警能力提供有用参考。

Identification method of key substation of DC bias distribution under multi DC monopole operation

With the construction of 1100kV UHVDC transmission project in China, the DC bias risk of Xinjiang power grid under the common influence of multiple DC grounding electrodes has become a new problem to be solved by the power sector. Based on the complex network theory, a method of identifying the key sites of DC bias under the joint action of multiple grounding electrodes is proposed. The influence of DC bias between sites and between sites and lines under the joint action of multiple grounding electrodes is studied. The key index which has an important influence on the distribution of DC bias considering the uncertainty of influencing factors is proposed to measure the characteristics of the action of multiple grounding electrodes. And the calculation method is given. Taking the 750kV UHV AC system in Xinjiang as an example, the key stations that affect the distribution of bias DC under the joint action of ± 1100kV quasi-East UHV DC and ± 800kV Tianzhong DC are analyzed. Compared with the actual test data in October 2018, the results verify the feasibility of the method and the validity of the key station criteria. The research results in this paper can effectively identify the characteristics of a transformer substation which plays a fundamental role in the distribution of magnetic bias, and provide a useful reference for improving the early warning ability of DC magnetic bias of power grid transformer.