## 3 Results and Discussion
### Results and Discussion for Area 2  
Detailed simulation results of the interconnected network in area 2 are given in Figures 20-22. The variations of \(ACE_{2}\) values throughout the entire simulation are illustrated in Figure 20a and the special cases are shown in Figure 20b,c. Here, the case of both sudden load fluctuations and the responses of the system variables for long-term power reduction in solar power plants, are observed. As noted in Table 6, the proposed GA-FLC reached a settling time value of 5.1 s and then quickly minimized the error. In addition, the proposed GA-FLC provided at least three times more overshoot than the GA-PID controller, as shown in Figure 20b and Table 6. In Figure 21, \(U_{(t)2}\), as the new status after controlling the \(ACE_{2}\) value, is demonstrated. The results of the PID, GA-PID, FLC, and the proposed GA-FLC controllers modelled to minimize the frequency variation, \(\Delta F_{2}\), in area 2, are revealed in Figure 22. In Figure 22b, it is shown that the GA-FLC maintains a balanced frequency in the second region. The power change over the connection line between area 1 and area 2 is shown in Figure 23. As shown in Figure 23 and Table 6, the frequency deviation in the second area is minimized. When the situation at the 5 th s is examined, the settling time value of the GA-FLC is set to 5.5 s, GA-PID is set to 5.9 s, FL is set to 8.3 s, and PID is set to 9.6 s.  
When the responses given by the controllers to the situation caused by the decrease in power at the 70 th s in the solar power plant are examined, it is seen that the settling time value of 70.1 s obtained by the proposed controller is the fastest and best result.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & \multirow{2}{*}{
\begin{tabular}{c} **Designs** \\ **Controller** \\ \end{tabular} } & \multicolumn{2}{c}{**Area 1**} & \multicolumn{2}{c}{**Area 2**} \\ \cline{3-8}  & & **Loads Increase** & \multicolumn{2}{c}{**Solar Power Decrease**} & \multicolumn{2}{c}{**Loads Increase**} \\  & & **(5 th s)** & \multicolumn{2}{c}{**(70 th s)**} & \multicolumn{2}{c}{**(5 th s)**} \\ \cline{3-8}  & & **Overshoots** & **Selling Time** & **Overshoots** & **Selling Time** & **Overshoots** & **Selling Time** \\ \hline \multirow{4}{*}{\(ACE\)} & PID & \(-0.00114\) & 13.1 & \(-0.00032\) & 80.5 & \(-0.00655\) & 8.9 \\ \cline{2-8}  & FL & \(-0.00025\) & 8.6 & \(-0.00012\) & 78.5 & \(-0.00267\) & 8.4 \\ \cline{2-8}  & GA-PID & \(-0.00016\) & 6.8 & \(-0.00009\) & 71.5 & \(-0.00177\) & 5.8 \\ \cline{2-8}  & GA-FLC & \(-0.00005\) & 5.5 & \(-0.00003\) & 70.6 & \(-0.00069\) & 5.1 \\ \hline \multirow{4}{*}{\(\Delta\)\(\mathcal{F}\)} & PID & \(-0.00665\) & 9.6 & \(-0.00077\) & 76.1 & \(-0.00128\) & 9.6 \\ \cline{2-8}  & FL & \(-0.00244\) & 9.1 & \(-0.00031\) & 73.4 & \(-0.00381\) & 8.3 \\ \cline{2-8}  & GA-PID & \(-0.00078\) & 6.7 & \(-0.00021\) & 70.5 & \(-0.00556\) & 5.9 \\ \cline{2-8}  & GA-FLC & \(-0.00018\) & 5.1 & \(-0.00008\) & 70.1 & \(-0.01224\) & 5.5 \\ \hline \multirow{4}{*}{\(\Delta\)\(\mathcal{F}\)\({}_{\Delta\text{F1-2}}\)} & PID & \(0.00207\) & - & - & - & - \\ \cline{2-8}  & FL & \(0.00084\) & - & - & - & - & - \\ \cline{1-1} \cline{2-8}  & GA-PID & \(0.00024\) & - & - & - & - & - \\ \cline{1-1} \cline{2-8}  & GA-FLC & \(0.00002\) & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 6: The obtained results.  
Figure 19: The detailed display of frequency, \(\Delta F_{1}\) change in area 1.  
Figure 21: \(U_{(02}\) changes using controllers in area 2: (a) PID; (b) GA-FLC; (c) GA-PID; (d) FLC.  
Figure 20: Changes in the \(ACE_{2}\) in the area 2: (a) during all simulation time; (b) 5 th change; (c) 18 th change.