## 3 Results and Discussion
### Optimization Results Using PSO without and with DG integration
#### 3.2.4 Scenario 4: Two DGs Placed at Buses 18 and 33 Based on the CF Ranking Method  
Considering the scenario in which two DGs were placed at the first two buses--18 and 33--identified by the CF ranking method, the results obtained for the system voltage profile are presented in Table 6. Based on the results presented in Table 6, it can be seen that the installation of multiple (two) DGs into the radial distribution network led to significant variation in voltage profiles compared with the base case scenario where no DGs were integrated into the system. As presented, all the voltages were significantly enhanced and all were within the acceptable voltage limits.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Bus No.**} & **Bus Voltage** & **Bus Voltage** & & **Bus Voltage** & **Bus Voltage** \\  & **Profile with No DG (pu)** & **Profile with** & **Bus No.** & **Profile with** & **Profile with** \\  & **No DG (pu)** & **DG (pu)** & & **No DG (pu)** & **DG (pu)** \\ \hline  
& \\ \hline \hline \end{tabular}
\end{table}
Table 4: Voltage profile without and with the integration of one DG at bus 18 into the IEEE 33-bus distribution system using the CF ranking method.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Bus No.**} & **Bus Voltage** & **Bus Voltage** & & **Bus Voltage** & **Bus Voltage** \\  & **Profile with No** & **Profile with** & **Bus No.** & **Profile with** & **Profile with** \\  & **DG (pu)** & **DG (pu)** & & **No DG (pu)** & **DG (pu)** \\ \hline
1 & 1.0000 & 0.9950 & **18** & **0.8297** & **0.9535** \\
2 & 0.9952 & 0.9981 & 19 & 0.9944 & 0.9835 \\
3 & 0.9824 & 0.9882 & 20 & 0.9885 & 0.9824 \\
4 & 0.9704 &  
As can be seen, the minimum voltage obtained after the integration of the DGs was 0.9890 pu, and this was associated with bus 30, while the maximum voltage of 1.0210 pu was obtained at the slack bus 1. The associated power loss in this case was 0.2348 MW, which is about a 77.1% decrease in power losses within the system. This shows a significant decrease in power loss compared to the power losses obtained in the base case scenario.  
3.2.5 Scenario 5: Two DGs Placed at Arbitrary Locations (Buses 16 and 32) Based on an Arbitrary Case  
In this scenario, two arbitrary locations where two DGs would be integrated were selected, which were buses 16 and 32. The results obtained for the system voltage profile, considering the system operating condition, are presented in Table 7. It can be seen from the results in Table 7 that the integration of two DGs at locations (buses 16 and 32) that were arbitrarily selected led to a slight improvement in the general voltage profile of the system. Although with this operating condition all the voltage magnitudes lay within the tolerable voltage limits, a decrease in the voltage magnitudes at some buses compared with the base case voltage profile was observed. For example, a decrease in voltage magnitudes was observed for buses 19 to 29. Under this scenario, it can be seen that the system operation was highly influenced by the positions where the DGs were placed. This was expected since the locations where the DGs were placed were arbitrarily selected. Considering this situation, the power loss obtained was 0.9815 MW, which shows a slight decrease of about 4.41% in power losses. Also, from the results presented in Table 7, the minimum voltage magnitude was 0.950 pu, associated with bus 30, while the maximum voltage profile was 1.0100 pu, associated with the reference bus 1.