A New Power System Frequency Response Model with Different Types of Generator Units

In order to accurately and quickly estimate the system frequency characteristics in large power grid after a disturbance, the paper presents a system frequency response modeling method based on the data-driven method. Firstly, the same type of turbine-governor models in system is aggregated into a single turbine-governor system by means of the parameter identification method. Then, the $\boldsymbol{H}_{\infty}$ norm based on the state space equation is used to reduce the order, and different types of turbine-governor systems with the same order are obtained. Finally, by using the idea of parameter aggregation, a first order turbine-governor system is obtained. According to the equivalent first-order model, the rate of change of frequency (RoCoF), the frequency nadir and the steady frequency after a disturbance can be quickly and accurately calculated. The method is validated in IEEE-39 node system and IEEE-118 system. The results show that the proposed method can meet the requirements of accuracy and greatly improve the computational speed.