基于安全风险概率的双特高压直流馈入网架关键断面通道检修评估方法研究

双特高压直流(Ultra High Voltage Direct Current, UHVDC)馈入同一网架,通道间存在强耦合性。合理制定受电端关键断面通道检修方案及评估方法,对于防御UHVDC受端交流系统失稳引发大面积停电事故至关重要。针对此问题,提出一种基于安全风险概率的UHVDC馈入网架关键断面通道检修评估方法。首先,在分析受端网架强度评估指标基础上提出基于多馈入短路比的网架强度评估方法,以短路比对网架结构耦合强度进行评估。然后,根据网架评估结果并综合考虑关键断面通道检修安全影响因素,提出高压直流馈入网架关键断面检修的安全风险量化评估方法,构建安全风险模糊评价模型,以各指标变化率对直流通道关键断面检修时整个网架运行可靠性进行量化评估。最后,以某省电网双馈入"青豫直流"及"天中直流"所构成的网架及实际案例仿真评估,验证所提出检修评估方法的有效性,识别出部分危险检修方式以引起生产部门重视并在实际操作中予以禁止。

Research on a maintenance evaluation method of the key section channel of a double UHVDC feed in a grid based on safety risk probability

A dual UHVDC is fed into the same grid, and there is strong coupling between the channels. It is necessary to develop a suitable maintenance evaluation method for the key section of the power receiving terminal. In order to do this, a maintenance evaluation method based on safety risk probability for the key section channel of double UHVDC feed in a grid is proposed. First, a grid strength evaluation method is established based on the analysis of the strength evaluation index of the grid receiving terminal. The coupling strength of the grid structure is evaluated by short circuit ratio. From the results of the evaluation and considering the safety factors of critical section channel maintenance, a quantitative assessment method of safety risk for UHVDC critical section maintenance is proposed. A fuzzy evaluation model of safety risk is constructed, and the reliability of the whole grid during the maintenance of the key section of UHVDC channel is evaluated quantitatively according to the change rate of each index. Finally, simulation and evaluation are carried out on the grid structure composed of Qing-Yu UHVDC and Tian-Zhong UHVDC in a provincial power grid, and the effectiveness of the proposed maintenance evaluation method is verified. Dangerous maintenance scenarios are identified by the proposed method and have gained the attention of the grid operation department and are forbidden in actual operation. This work is supported by the National Key Research and Development Program of China (No. 2018YFB0905200) and the Project of State Grid Henan Electric Power Company (No. 52170219000M).