## 5 Simulation and Verification of Hybrid Reactive Power Compensation Program
### Static Voltage Stability Simulation Verification  
By improving the particle swarm algorithm, as discussed in Section 4 of this paper, when the fixed compensation capacity of the parallel capacitor is set to 10 MVar, the best compensation effect should be obtained when the SVG compensation capacity is set to 9.2 MVar. In order to verify the correctness of the method proposed in this paper, through the P-U characteristic curve of the wind farm in the eastern area of Mahuangou in the Santanghu wind area, the static voltage stability under the control of different types of reactive power compensation devices was analyzed by setting different configuration programs combined with the methods in the literature [5, 11, 13, 17, 18, 26, 27]. Taking the Shengtian and Huaneng wind farms in weak areas as examples, the following six programs are simulated and compared. Program 1: no reactive power compensation device. Program 2: set 20 MVar SC capacitor banks. Program 3: set 20 MVar SVC as wind farm reactive power compensation equipment. Program 4: set the combined reactive power compensation device proposed in this paper; the parallel capacitor capacity is 10 MVar, and the SVC compensation capacity is 9.2 MVar. Program 5: set 20 MVar SVG as the reactive power compensation equipment of the wind farm. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Wind Area** & **Wind Farm Bus (220 kV)** &
\begin{tabular}{c} **Voltage Stability Modal** \\ **Values/p.u.** \\ \end{tabular} \\ \hline \multirow{4}{*}{Southeast wind area} & Kushui West wind farm & 0.027562346 \\  & Kushui East wind farm & 0.025684795 \\  & Yandun South wind farm & 0.021016546 \\  & Yandun West wind farm & 0.020150621 \\  & Yandun North wind farm & 0.016542154 \\ \hline \multirow{4}{*}{Central Hami wind area} & Naomaohu wind farm & 0.043562145 \\  & Guanghui Naomaohu wind farm & 0.040561425 \\  & Shisanjianfang wind farm & 0.045462154 \\ \hline \multirow{4}{*}{Santanghu wind area} & Red Star wind farm & 0.032456218 \\  & Wangyangtai wind farm & 0.027658974 \\ \cline{1-1}  & Wangyangtai east wind farm & 0.028562016 \\ \cline{1-1}  & Wangyangtai west wind farm & 0.027146484 \\ \cline{1-1}  & Mahuanggou west wind farm & 0.015025153 \\ \cline{1-1}  & Mahuanggou east wind farm & 0.014876213 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The 220 kV aggregate busbar value of the wind farm in the Hami area. Program 1: In the case that there is no reactive power compensation device in either wind farm when the active power is about 385 MW, the busbar voltage drops rapidly and quickly reaches the limit instability point. Program 2: When the SC-type capacitor bank is put in, it leads to a large oscillation of the wind turbine terminal voltage. The active power is about 500 MW when the bus voltage shows a sudden drop, but the static voltage stability limit of the wind farm convergence area is improved compared to option 1. Program 3: When the static reactive power compensation device SVC is put in, compared to the first two programs, the ultimate destabilizing active power output of the wind farm voltage can reach 543 MW before the voltage destabilization phenomenon finally occurs. This raises the voltage destabilization threshold and can further enhance the static voltage stability limit of the wind farm cluster to a certain extent. Program 4: When combined SVC and shunt capacitor reactive power compensation equipment are used, the SVC can smooth the reactive power output and further maintain a constant voltage at the controlled bus within the reactive power regulation capacity. Compared with the aforementioned programs, it can more significantly improve the static voltage stability limit, for which the wind farm group's active output reaches 570 MW when voltage instability eventually occurs. Figure 10: P-U characteristic curve in programs 5 and 6. Figure 9: P-U characteristic curve in programs 3 and 4.