适用于输变电联合系统的改进CESMC可靠性评估方法

Improved CESMC Based Reliability Assessment Method for Composite Transmission and Substation System

传统的序贯交叉熵(cross-entropy sequential Monte Carlo,CESMC)方法无法对包含多状态变电站等效元件模型的输电系统进行可靠性评估。为此,首先对变电站等效状态数目进行分析,并基于马尔可夫与交叉熵重要性抽样理论推导了变电站等效多状态元件的最优可靠性参数表达式以及参数优化的迭代计算式,提出了一种适用于输变电联合系统的改进CESMC可靠性评估方法,实现了对传统CESMC可靠性评估方法适用范围的扩展,解决了序贯交叉熵无法应用于多状态系统可靠性评估的难题。结合改进CESMC方法,实现包含变电站等效元件的输电系统可靠性评估加速,进一步构建了输变电联合系统可靠性评估模型。通过对IEEE-RTS79测试算例进行可靠性评估,验证了该方法的有效性,仿真结果表明,该方法可以在保证计算精度的前提下,较大地提升输变电联合系统可靠性评估的效率,具有一定的实用价值。

It is unable to analyze the reliability of the composite transmission and substation system which incorporates the equivalent multi-state substation components by using traditional cross-entropy sequential Monte Carlo(CESMC)method.Therefore,this paper first analyzes the number of equivalent states of the substation,and derives the optimal reliability parameter expression and parameter optimization iterative formula for the equivalent multi-state components of the substation based on Markov and cross-entropy importance sampling theory.A modified CESMC reliability assessment method suitable for the transmission and transformation joint system is proposed,which expands the scope of application of the traditional CESMC reliability assessment method and solves the problem that sequential cross-entropy can not be applied to multi-state system reliability assessment.Combined the improved CESMC method,the reliability assessment of the power transmission system containing equivalent components of the substation is accelerated,and a reliability assessment model for the transmission and transformation joint system is further constructed.Finally,as a case for testing the proposed model,the reliability of IEEE-RTS79 system is analyzed.The simulation results show the availability and the advantages of the proposed method when assessing the reliability of the composite system.Meanwhile,the influence of the substations on the reliability of the transmission system can also be found according to the results.