## 4 Overcurrent Protection Coordination Results, Analysis and Discussion
### Protection Coordination Results in Scenario 4
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**The OCRs**} & \multirow{2}{*}{**50P**} & \multirow{2}{*}{**50G**} & \multirow{2}{*}{**50G**} & \multicolumn{4}{c}{**51P**} & \multicolumn{4}{c}{**51G**} \\ \cline{5-12}  & & & & **GA** & **GSA** & **PSO-GSA** & **GA** & **GSA** & **PSO-GSA** \\ \hline \multirow{5}{*}{\begin{tabular}{c} The REC \\ Can-Thanh-Vo \\ OCR \\ \end{tabular} } & \multirow{5}{*}{\(I_{f}\)} & \multirow{5}{*}{18,791 A} & \multirow{5}{*}{\(I_{f}\)} & A & 10.84 & 42.61 & 15.58 & A & 21.36 & 70.52 & 149.95 \\  & & & & B & 1.24 & 2.39 & 1.47 & B & 2.21 & 2.40 & 2.50 \\  & & & & C & 1.08 & 0.39 & 1.12 & C & 0.94 & 0.60 & 0.08 \\ \cline{2-12}  & & & & & TDS & 0.13 & 0.14 & 0.12 & TDS & 0.19 & 0.09 & 0.05 \\ \cline{2-12}  & & & & & TDS & 0.13 & 0.14 & 0.12 & TDS & 0.19 & 0.09 & 0.05 \\ \cline{2-12}  & & & & & & \multicolumn{4}{c}{The tripping time of the relay for the typical fault at Bus 3:} \\ \cline{5-12}  & & & & & \(t_{trip}\) & 0.64 s & 0.63 s & 0.65 s & \(t_{trip}\) & 0.64 s & 0.63 s & 0.65 s \\ \hline \multirow{5}{*}{\begin{tabular}{c} The REC \\ Can-Thanh-Vo \\ OCR \\ \end{tabular} } & \multirow{5}{*}{\(I_{f}\)} & \multirow{5}{*}{1798 A} & \multirow{5}{*}{\(I_{f}\)} & A & 8.43 & 72.23 & 0.01 & A & 18.43 & 77.10 & 1.52 \\  & & & & B & 2.42 & 2.44 & 0.02 & B & 2.31 & 2.37 & 1.83 \\ \cline{2-12}  & & & & C & 0.50 & 0.62 & 0.29 & C & 0.97 & 0.77 & 0.01 \\ \cline{2-12}  & & & & & TDS & 0.26 & 0.05 & 0.50 & TDS & 0.12 & 0.04 & 1.16 \\ \cline{2-12}  & & & & & & \multicolumn{4}{c}{The tripping time of the relay for the typical fault at Bus 3:} \\ \cline{5-12}  & & & & & \(t_{trip}\) & 0.32 s & 0.31 s & 0.33 s & \(t_{trip}\) & 0.32 s & 0.31 s & 0.33 s \\ \hline \multirow{5}{*}{\
\begin{tabular}{c} The REC \\ Can-Thanh \\ 163 OCR \\ \end{tabular} } & \multirow{5}{*}{0.01 s} & \multirow{5}{*}{\(t_{trip}^{defined}\)} & A & 1.10 & 53.82 & 0.01 & A & 1.93 & 39.27 & 0.01 \\  & & & & B & 1.73 & 1.87 & 0.71 & B & 2.37 & 2.28 & 1.31 \\ \cline{1-1} \cline{2-12}  & & & & & C & 0.00 & 0.65 & 0.01 & C & 0.11 & 0.77 & 0.00 \\ \cline{1-1} \cline{2-12}  & & & & & TDS & 0.04 & 0.01 & 0.52 & TDS & 0.03 & 0.01 & 2.98 \\ \cline{1-1} \cline{2-12}  & & & & & & \multicolumn{4}{c}{The tripping time of the relay for the typical fault at Bus 3:} \\ \cline{5-12}  & & & & & \(t_{trip}\) & 0.01 s & 0.01 s & \(t_{trip}\) & 0.01 s & 0.01 s & 0.01 s \\ \hline \multirow{5}{*}{
\begin{tabular}{c} A CB GEN \\ OCR \\ \end{tabular} } & \multirow{5}{*}{\(I_{f}\)} & A & 4.39 & 57.46 & 0.01 & A & 0.23 & 67.95 & 0.01 \\  & & & B & 2.41 & 2.17 & 2.50 & B & 2.45 & 2.24 & 2.25 \\ \cline{1-1} \cline{2-12}  & & & & C & 1.18 & 0.59 & 0.05 & C & 0.76 & 0.80 & 0.80 \\ \cline{1-1} \cline{2-12}  & & & & TDS & 0.09 & 0.01 & 7.16 & TDS & 0.35 & 0.01 & 0.45 \\ \cline{1-1} \cline{2-12}  & & & & & \multicolumn{4}{c}{The tripping time of the relay for the typical fault at Bus 3:} \\ \cline{1-1} \cline{2-12}  & & & & & \(t_{trip}\) & 0.35 s & 0.32 s & 0.35 s & \(t_{trip}\) & 0.35 s & 0.32 s & 0.35 s \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Optimal protection coordination results of the OCRs in Scenario 4 and their tripping time when the fault is at Bus 3. Figure 13: _Cont_. In summary, the optimal protection coordination results of the related OCRs regarding four different operation scenarios of the real 22 kV DG-based distribution system have been analyzed and validated in this section. These relay coordination results of Scenarios 1, 2, 3 and 4 can be briefly concluded as follows. * Three meta-heuristic algorithms, GSA, hybrid PSO-GSA and GA have efficiently solved the adaptable and scalable protection coordination problem of the OCRs in the DG-integrated DN as demonstrated in Figures 11-13.