基于调速系统等值模型的电力系统发生扰动后最低频率预测

Minimum frequency prediction of power system after disturbance based on equivalent model of governor system

电力系统发生扰动后的最低频率预测是电力系统频率安全稳定分析的重要内容。提出一种基于调速系统一阶等值模型的电力系统发生扰动后最低频率预测模型。在传统的平均频率响应模型的基础上,将各调速系统的动态模型等值为一阶模型,并对调速系统的反馈输入进行不同形式的线性化近似,进而实现对平均频率响应闭环模型框架的开环处理,最终根据最低频率出现时刻的边界条件,建立耦合系统最大频率偏差的非线性代数方程。通过求解非线性代数方程组即可得到最低频率。通过与PSS/E中10机39母线系统的仿真结果进行比较,证明了所提算法能够快速、准确地计算得到系统发生扰动后的最低频率。

The minimum frequency prediction of power system after disturbance is an important part of power system frequency safety and stability analysis. A minimum frequency prediction model of power system after disturbance based on the first-order equivalent model of governor system is proposed. On the basis of the traditional average frequency response model,the dynamic model of each governor system is equivalent to the first-order model,and different types of linearized approximation of the governor system’s feedback input are carried out to realize the open-loop processing of the closed-loop model framework of average frequency response. Finally,according to the boundary conditions of minimum frequency occurrence time,the nonlinear algebraic equation of the maximum frequency deviation of the coupled system is established,by solving which,the minimum frequency is obtained. By comparing the calculative results of the proposed model with the simulative results of 10-machine 39-bus system in PSS/E,it is proved that the proposed model can quickly and accurately calculate the minimum frequency of power system after disturbance.