## 5 Results and Discussion
### Results of 69-Bus Radial Distribution System
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Load Levels**} & \multirow{2}{*}{**Parameters**} & \multicolumn{3}{c}{**After Reconfiguration**} \\ \cline{3-5}  & & **Case 2: PSO** & **Case 3: IPSO** & **Case 4: IEPSO** \\ \hline \multirow{4}{*}{Light Load} & Switches & 8, 16, 69, 54, 43 & 14, 20, 8, 9, 69 & 38, 26, 69, 53, 13 \\  & TPL (kW) & 36.5 & 26.70 & 18.80 \\  & VSI min & 0.8423 & 0.8718 & 0.9298 \\  & Voltage profile (p.u.) & 0.9586 & 0.9663 & 0.9821 \\  & Computational time (s) & 44.078821 & 5.646365 & 6.350293 \\ \hline \multirow{4}{*}{Nominal Load} & Switches & 45, 16, 53, 8, 69 & 52, 21, 11, 7, 13 & 9, 13, 61, 52, 19 \\  & TPL (kW) & 145.5 & 69.0 & 61.9 \\  & VSI min & 0.7102 & 0.7772 & 0.8576 \\  & Voltage profile (p.u.) & 0.9180 & 0.9389 & 0.9634 \\  & Computational time (s) & 42.625656 & 6.981524 & 7.968446 \\ \hline \multirow{4}{*}{Heavy Load} & Switches & 17, 69, 13, 10, 57 & 13, 5, 59, 69, 58 & 7, 19, 69, 70, 57 \\  & TPL (kW) & 267.50 & 160.00 & 143.60 \\ \cline{1-1}  & VSI min & 0.6347 & 0.7401 & 0.7930 \\ \cline{1-1}  & Voltage profile (p.u.) & 0.8926 & 0.9348 & 0.9442 \\ \cline{1-1}  & Computational time (s) & 45.526328 & 7.059524 & 7.736560 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The performances of PSO, IPSO and IEPSO for DNR implementation in 69-bus radial distribution system. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Load Levels**} & \multirow{2}{*}{**Parameters**} & \multicolumn{3}{c}{**After Reconfiguration**} \\ \cline{3-5}  & & **Case 2: PSO** & **Case 3: IPSO** & **Case 4: IEPSO** \\ \hline \multirow{4}{*}{Light Load} & Switches & 57, 23, 4, 69, 13 & 19, 57, 45, 10, 12 & 17, 41, 58, 59, 11 \\  & DG sizing (MW) & 1.0100 & 1.0598 & 1.0911 \\  & TPL (kW) & 29.3 & 24.50 & 18.00 \\  & VSI min & 0.9205 & 0.9476 & 0.9649 \\  & Voltage profile min (p.u.) & 0.9801 & 0.9866 & 0.9911 \\  & Computational time (s) & 25.587512 & 6.312718 & 3.691640 \\ \hline \multirow{4}{*}{Nominal Load} & Switches & 53, 4, 14, 69, 20 & 55, 12, 14, 9, 16 & 5, 60, 69, 13, 11 \\  & DG sizing (MW) & 1.0930 & 1.0632 & 1.0376 \\ \cline{1-1}  & TPL (kW) & 108.1 & 62.7 & 54.5 \\ \cline{1-1}  & VSI min & 0.7356 & 0.8328 & 0.9137 \\ \cline{1-1}  & Voltage profile min (p.u.) & 0.9349 & 0.9553 & 0.9777 \\ \cline{1-1}  & Computational time (s) & 28.681047 & 7.874213 & 8.879116 \\ \hline \multirow{4}{*}{Heavy Load} & Switches & 54, 15, 10, 69, 13 & 22, 18, 69, 7, 54 & 9, 20, 53, 14, 41 \\ \cline{1-1}  & DG sizing (MW) & 1.0473 & 1.2238 & 1.0572 \\ \cline{1-1}  & TPL (kW) & 237.3 & 138.30 & 118.90 \\ \cline{1-1}  & VSI min & 0.6653 & 0.8127 & 0.8429 \\ \cline{1-1}  & Voltage profile min (p.u.) & 0.9031 & 0.9502 & 0.9595 \\ \cline{1-1}  & Computational time (s) & 35.443263 & 9.672387 & 5.418619 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: The performances of PSO, IPSO and IEPSO for DNR with DG sizing implementation in 69-bus radial distribution system. for nominal load in case 2 IEPSO technique gave the most reduction for TPL by 76.28%, 34.39% highest VSI, but slightly defeated in computational time compared to IPCSO by 1 s at nominal load. Finally, for heavy load in case 2 IEPSO technique gave the most reduction for TPL by 79.26%, 58.41% highest VSI, and the fastest in computational time compared to other techniques at heavy load. Figures 8 and 9 show the stability is improved for all cases, especially when the proposed algorithm is applied on 69-bus test system. Generally, by increasing the load levels, the VSI will decrease. Thus, the stability of the system is towards the voltage collapse with increasing load demand. Figure 10 shows the comparison of TPL and VSI for three cases which are base case, DNR without DG and DNR with DG for light, nominal and heavy load condition in 69-bus system. From the figure, it is shown that TPL is slightly reduced with DNR implementation. However, the TPL has a significant reduced when DNR and DG was applied to the system. Figure 8: Voltage stability index for different load levels DNR in 69-bus test system.