基于改进FD法的柔性直流输电系统可靠性评估

在直流系统可靠性评估中,传统FD法需要建立状态空间图,求解过程繁琐。提出一种基于参数矩阵化的FD法,即将所有子系统的相关参数矩阵化,包含容量矩阵、容量概率矩阵、状态转移率矩阵。通过矩阵运算实现子系统组合,从而避免建立状态空间图,在保证计算精度的同时,使子系统组合计算简明快速,克服了传统方法在元件众多结构复杂时计算困难的弊端。对一个双极两端柔性直流输电系统进行了可靠性建模与评估,并研究了元件故障率变化对柔性直流输电系统可靠性的影响。

Reliability assessment of the VSC-HVDC transmission system based on a modified FD method

The traditional FD method is based on state-space diagrams, which would be extremely complex if the number of system states increases. A modified FD method is proposed and applied to the reliability assessment of the VSC-HVDC transmission system. In the proposed method, parameter matrices, including capacity matrix, probability matrix and departure rate matrix, are introduced into the reliability evaluation procedure to replace the state-space diagrams. A case study is conducted on the basis of the proposed method. Results show that the matrix based method overweighs the traditional FD method on both the calculation speed and simplicity, thereby providing an efficient approach to assess the reliability of VSC-HVDC transmission system. Furthermore, the impact of parameter variance on the system reliability is analyzed in order to identify the weakest component in a VSC-HVDC transmission system.