非等分布置的特高压直流输电接地极导流系统设计

为满足特高压直流输电(UHVDC)工程传输容量不断提升的需求,针对接地极导流系统等分布置常规方案的技术缺陷,提出适用于额定直流电流6 250 A及更高的UHVDC接地极导流系统"外六内三"的非等分布置方案。基于电力系统行业标准规定的2种N-1故障及行标未规定但实际运行中可能出线的3种N-2故障,给出接地极导流系统通流能力阈值计算方法,并据此给出"外六内三"非等分方案下接地极导流系统稳态通流及故障态校验。搭建适用于实际工程的仿真模型,详细研究其导流电缆截面选型依据,并根据文中提出方案与常规方案的经济性对比分析,给出非等分布置时高压直流输电接地极导流系统通用设计。

Current guiding system design of electrode for UHVDC transmission with non-equally divided scheme

For the demand of transmission of bulk power through UHVDC, based on the faultiness of the equally divided current guiding system of traditional electrode design, this paper proposes a new outer-6 and inner-3 non-equally divided scheme to optimize the current guiding system design of the electrode for the UHVDC transmission system with 6 250 A rated dc current or higher. Based on the two N-1 faults which stipulated in grid code and other three N-2 faults which occur during real operation, the threshold value of current guiding capability of current guiding system of UHVDC electrode is calculated. Besides, the current loading capacity calculation of guiding system under both normal operation and fault condition with the proposed outer-6 and inner-3 scheme is analyzed. A simulation model is established in the ETTG to discuss the selection of section of current guiding cable. Moreover, an economic comparison between the non-equally divided scheme proposed in this paper and traditional equally divided scheme is conducted. The general conclusion of the electrode current guiding system design with non-equally divided scheme is summarized in the end.