并联换流器特高压直流输电系统可靠性研究

Reliability Research for UHVDC Transmission System with Parallel Converters

特高压直流输电工程输送容量大、送电距离远,其安全、可靠运行具有重要的现实意义。该文建立了并联换流器特高压直流输电系统的"故障树"模型,可以有效计算特高压直流输电系统的强迫能量不可用率和单、双极停运次数等可靠性指标;然后,提出了一种新的反映设备影响系统可靠性的灵敏度指标,可以有效发现钳制系统可靠运行的薄弱环节。最后,基于国家电网公司近10年的直流工程可靠性运行统计数据,对3种并联换流器特高压直流输电系统主接线方案,进行了可靠性指标计算和对比分析,并完成了设备影响系统可靠性指标的灵敏度分析,确定了影响系统强迫能量不可用率和单、双极停运次数的关键环节。结果表明,本研究能够确定可靠性高的并联换流器特高压直流输电系统拓扑结构,可以为提高特高压直流工程的可靠性提供重要的参考信息。

The safety and reliability operation of UHVDC projects, which are characterized by large transmission capacity and long working distance, has vital practical significance. This paper establishes a fault-tree model of UHVDC system with parallel converters, which can help to calculate the forced energy unavailability, monopole forced outage times and bipole forced outage times of UHVDC projects effectively. Then, this paper proposes several sensitivity indices which show the impact of every equipment on the reliability of UHVDC system, thus to effectively find the weak points of the project. Finally, based on the statistical data of the reliability of HVDC projects of SGCC （ State Grid Corporation of China） in the past 10 years, this paper calculates and compares the reliability indices for the main wiring schemes of three different kinds of UHVDC system with parallel converters. Moreover, this paper completes the sensitivity analysis on the reliability index of system affected by equipments, and finds the key links which affect the forced energy unavailability, monopole forced outage times and bipole forced outage times. The results show that this research can determine the topology Of high- reliability UHVDC system with parallel converters, and provide important reference information for the reliability improvement of UHVDC projects.