基于解析法的概率暂态稳定扰动后初值计算

根据一段时间内负荷和发电机的运行曲线,采用解析法计算和分析了在电力系统受到扰动后瞬间节点电压和电流的均值和协方差,完成了解析法概率暂态稳定分析的初值计算。以节点注入功率和PV节点电压运行曲线构成系统的多运行方式,计及了节点注入之间的相关性,在发电机变量的概率特性计算基础上,推导了扰动后节点电压、电流的均值和协方差的线性化算式。为便于协方差的计算,由电力系统的运行特点提出了变阻抗负荷模型,对其余的各种负荷和发电机模型也提出了相应的解决方法。根据线性化和完整二阶2种概率潮流的计算结果,以三相短路故障为例,在一8机系统的算例上完成了计算分析。结果表明,短路电压均值的计算精度较高,短路电压协方差的误差较大。

Calculation of post-disturbance initial value for probabilistic transient stability analysis based OH multi-operating conditions

The post-disturbance initial value is obtained for probabilistic transient stability analysis, which calculates the means and covariances of post-disturbance nodal voltage and current of power system based on the operating curves of loads and generators for a period.The operating curves are formed with nodal injections and PV voltages,considering the relativity of nodal injections.The expressions of post-disturbance mean nodal voltage and current and the linear expressions of eovariances are deduced based on the probabilistie characteristic calculation of generators.For the convenience of eovariance calculation,the variable impedance model,as well as the models of various loads and generators,is introduced according to the operating characteristics of power system.Based on the results of probabilistie power flow calculations with the linearized model and the complete second order model,case study of an eight-machine system is carried out for three-phase short -circuit fault,which shows that,compared with the eovariances,the means of short-circuit voltage have better computational accuracy.