基于k／n(G)模型的柔性直流输电系统换流阀可靠性建模与冗余性分析

Reliability Modeling and Redundancy Analysis of Converter Valves for VSC-HVDC Power Transmission System Based on k-out-of-n:G Model

采用电压源型换流器以及脉宽调制技术的柔性直流输电系统具有功率控制灵活、可向有源和无源网络输电、产生的谐波含量小等优点。文章主要对柔性直流输电换流器的换流阀进行可靠性建模与分析。首先介绍换流阀及其控制、冷却和保护系统的内部结构和功能。然后基于k/n(G)模型,以ABB公司StakPakIGBT换流阀为例,建立换流阀模块及其次级子模块的可靠性数学模型。通过计算,得到不同电压等级和不同冗余下的换流阀可靠性指标,最后选择合理的冗余方案。

VSC-HVDC power transmission system based on voltage source converter （VSC） and pulse width modulation （PWM） control possesses following advantages： flexible power control, capability of transmitting power to active and passive network as well as lower harmonics amount, etc. The reliability model and analysis method of the converter valves in VSC-HVDC system is mainly concerned. The authors present the internal structure and functions of converter valve and its control, cooling and protection system. Based on the k-out-of-n： G model and taking the StakPak IGBT from ABB Semiconductors for example, the mathematical reliability model for converter valve and its sub-module is established. By means of calculation and analysis, the reliability indices of converter valve under various voltage classes and different redundancies are obtained, then rational redundant scheme is chosen.