UHVDC系统可靠性分层等值与灵敏度分解

摘要

To quantify reliability and parametric sensitivity of the ultra HVDC (UHVDC) system, hierarchical models for reliability equivalent and improved F&D method are newly proposed. Based on the system configuration and the operation characteristics, multiple capacity levels, transformer winding connections, and single station sharing spare are considered. The UHVDC system is classified to several sub-systems, whose state spaces are derived and combined to yield the whole state space. The traditional frequency and duration (F&D) method necessitates manual search and calculating transition frequency to acquire transition rate, which is fallible, and the calculation efforts increases with the states. Improved F&D method based on matrix description yields relation of the transition matrices before and after equivalence. Sensitivity between system reliability indices and components’ reliability parameters is finally derived. Numerical results show that the proposed model and algorithm can quantify the reliability of UHVDC system and determine the critical parameter and weak component to unavailability of UHVDC system, which validates feasibility and effectiveness of the proposed model and algorithm.%为了量化特高压直流（UHVDC）系统可靠性及其参数灵敏度，提出了可靠性分层等值模型和改进频率和持续时间（F&D）算法。基于UHVDC系统结构和运行特点，计及多容量水平、换流变压器接线形式和单端整体备用模式，将其划分若干个子系统，分别建立状态空间，逐层向上等值，得到整个系统状态空间。传统F&D法需人工查找和计算等值转移频率后才可计算出等值转移率，易出错且计算量随着状态空间维数增加。基于矩阵描述的改进F&D算法，可直接建立等值前后转移率矩阵关系，以及系统可靠性指标对底层元件可靠性参数的灵敏度分解关系。算例分析结果表明，所提模型和算法能够定量评估UHVDC系统可靠性，明确了影响UHVDC可靠性的关键参数和薄弱环节，证实了方法的可行性与有效性。