多运行方式下发电机变量的概率特性计算

实际电力系统运行中，发电机和负荷的功率随时都在变化，发电机中各状态变量（功角、转速等）和代数变量（交轴、直轴的电压和电流等）分布在一定范围内。计算发电机变量的概率特性能使运行人员获得较完备的系统运行信息，是基于多运行方式的概率暂态稳定分析的基础。均值和协方差一定程度上可以描述这些随机变量的概率分布特性。文中以节点注入功率和 PV节点电压运行曲线为基础，假定发电机各变量服从正态分布，依据概率潮流计算和随机变量数字特征的基本性质，推导了发电机变量的均值计算公式和协方差的线性化算式。最后对8机系统进行了计算分析。

Probabilistic Characteristic Calculation of Generator Variables Under Multi-operating Conditions

In the practical power system operation,the powers of generators and loads are changing constantly,and the state variables(e.g.power angle,rotating speed)and algebraic variables(e.g.voltages and currents of dq-axis)are fluctuant within a certain range.Probabilistic characteristic of generator variables provide operators more comprehensive operating information and they are the base of the probabilistic transient stability analysis in multi-operating conditions.To some extent,expectations and covariances can describe the probabilistic distribution characteristics of these variables.Based on the operating curves of nodal injections and PV voltages and with the assumption that all generator variables obey the normal distribution,the expectation expressions and linear covariance expressions of generator variables are deduced according to the probabilistic load flow analysis and the basic property of numerical characteristics of random variables.In the end,the studies are carried out on an eight-machine system.