基于随机微分方程的光伏电源机电随机特性的代数建模方法及应用

Algebraic Modeling Method and Application of Electromechanical Random Characteristics of Photovoltaic Power Supply Based on Stochastic Differential Equation

以光伏电源为代表的逆变型新能源具有强随机性,且不具备转动惯量,无法套用传统发电机特性模型和电力系统机电暂态分析方法中的转子运动方程。该文研究了用于代数分析的光伏电源随机性建模方法,构造单位随机变量为Gauss白噪声,并根据光伏电源并网装置的结构建立随机微分方程,进而推导出随机微分方程的解析解,然后分析了同时考虑多随机因素时的建模方法,并通过Maple软件计算出方程的数值解,与MATLAB/Simulink平台上仿真电路的波形相对比,结果验证了所提建模方法的有效性。最后,研究了所建模型在新型电力系统机电暂态分析中的应用,通过算例得到了系统稳定性的充分条件临界值,突破了因转动惯性缺失而带来的新型电力系统机电暂态计算瓶颈。

The inverter new energy represented by the photovoltaic power supply has strong randomness and no moment of inertia,which can not be applied to the traditional generator characteristic model and the rotor motion equation in the electromechanical transient analysis method of the power system.This paper researches the randomness modeling method of photovoltaic power supply for algebraic calculation.In this paper,the unit random variable is Gauss white noise.The stochastic differential equation is established according to the structure of the photovoltaic power grid-connected device,and then the analytical solution of the equation is derived.Then,the modeling method,which considers multiple random factors,is analyzed.After that,the numerical solution of the equation is calculated by Maple software and compared with the waveform of the simulation circuit on the Matlab/Simulink platform;the results verify the effectiveness of the modeling method proposed in this paper.Finally,the application of this model in the electromechanical transient analysis of the new power system is researched.The sufficient condition critical value of the system stability is obtained by the Example,which breaks through the electromechanical transient calculation bottleneck caused by the new energy's non-rotational inertia.