**2. Power System Modeling**

A mathematical model has been designed to analyze the proposed VSWT adaptive frequency control in an isolated power system. A generic wind-thermal isolated system is considered in this study (refer to Figure 2), including steam, diesel, gas, and combined cycle units, as well as wind power plants. Consequently, the model developed in Matlab/Simulink (2016) includes these thermal units, one equivalent VSWT acting as the wind power plants, the automatic generation control (AGC), the power system, and the power demand (including a load shedding scheme). The electromagnetic transients are supposed to be much faster than the other components of the model, and their influence in the system's dynamics is omitted [61]. In Figure 3, the block diagram of the power system under study can be seen.

**Figure 2.** Simplified one-line diagram of the generic isolated power system.

**Figure 3.** Block diagram of the frequency analysis model.
