计及风电随机激励的电力系统暂态稳定分析

Transient stability analysis of power system considering wind-power stochastic excitation

为了探讨风电随机激励对电力系统暂态稳定的影响,提出一种基于随机微分理论对含风电电力系统进行建模和稳定分析的方法。首先将异步风机机械功率作为随机激励,在暂态过程中利用伊藤型随机微分方程对异步风机的转子运动方程进行建模,将传统的微分代数方程模型扩展成随机微分代数方程模型;然后针对新的模型,通过时域仿真进行求解,分析风电功率随机波动对电力系统暂态过程的影响。算例结果表明:相比于确定性和概率性暂态稳定分析方法,所提方法能够更好地揭示风电不确定性对电力系统暂态稳定性的影响。

In order to study the impact of wind-power stochastic excitation on the transient stability of power system,a modeling and stability analysis method based on stochastic differential theory is proposed for power system with wind power,which takes the mechanical power of asynchronous wind turbine as the stochastic excitation,applies the stochastic differential equation in the transient process to model the rotor motion equation of asynchronous wind turbine for expanding the traditional DAE（Differential Algebraic Equations） model into SDAE（Stochastic Differential Algebraic Equations） model,which is then solved by the time-domain simulation to analyze the impact of stochastic turbulence of wind power on the transient process of power system at any moment. Results of case study show that,compared with the deterministic and probabilistic transient stability analysis methods,the proposed method reveals more accurately the impact of wind-power uncertainty on the transient stability of power system.