中文摘要：

由于高压直流输电（HVDC）系统结构复杂、元件众多，各元件对系统不可靠性的影响各不相同，如能找到一种不可靠性分摊方法，给出各元件对系统不可靠性的贡献大小，以确定直流输电系统的薄弱环节，将为运行和规划人员提供一种新的可靠性分析方法。针对该问题，提出基于比例分摊思想的系统不可靠性跟踪准则，结合可靠性计算中的子系统划分，又提出了直流输电系统可靠性跟踪的2次分摊方法。在子系统可靠性跟踪中，应用比例分摊准则得到各子系统内部元件对子系统可靠性指标的分摊；在整个直流系统可靠性跟踪中，基于该准则得到各子系统可靠性指标对直流系统各可靠性指标的分摊；最后合并2次分摊结果即可得到各元件对系统可靠性指标的分摊。采用某工程算例进行测试分析，结果证实该文提出的可靠性跟踪方法能够将HVDC输电系统可靠性指标公平合理地分摊到各元件或子系统，并有效地辨识了系统的薄弱环节。

英文摘要：

Generally, HVDC transmission system has a quite complex structure with a large number of components. As is well known, each component has a different impact on the system reliability. The technique of determining the contribution of each component to the system unreliability can be used to identify the system weak parts and provide a useful tool for the decision-making on HVDC system operation and planning processes. This paper proposes an unreliability-tracing principle based on the proportional sharing principle （PSP）, and an unreliability-tracing model for HVDC transmission systems. The PSP was used in this model twice based on the sub-system division scheme. In the unreliability-tracing process of the sub-system, the contribution of each component to a sub-system unreliability index can be calculated using the PSE In the unreliability-tracing process of the whole system, the contribution of each sub-system to the system unreliability can also be calculated using the PSP. The contribution of each component to the system unreliability can be obtained by combining the two contribution results. The case study indicated that the proposed technique can distribute the HVDC transmission system reliability index to components or sub-systems impartially and reasonably, and it can also be used to identify the system weak parts.