## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Protection Zone**} & \multirow{2}{*}{**Fault**} & \multirow{2}{*}{**Protection Device**} & \multirow{2}{*}{**Without DG**} & \multicolumn{2}{c}{**25\% DG**} & \multicolumn{2}{c}{**50\% DG**} & \multicolumn{2}{c}{**75\% DG**} \\  & & & & & **(1 MW)** & & **(2 MW)** & & **(3 MW)** \\ \cline{3-10}  & & & \(I_{sc}\) **[A]** & \(t\) **[s]** & \(I_{sc}\) **[A]** & \(t\) **[s]** & \(I_{sc}\) **[A]** & \(t\) **[s]** & \(I_{sc}\) **[A]** & \(t\) **[s]** \\ \hline \multirow{2}{*}{Zone 1} & \multirow{2}{*}{Bus 645} & R632 & 536.3 & 0.300 & 513.6 & 0.350 & - & - & - & - \\  & & F645 & - & - & 726.4 & 0.010 & - & - & - & - \\ \hline \multirow{2}{*}{Zone 2} & Fault F1 & R632 & 488.3 & 0.380 & 465.1 & 0.389 & 455.5 & 0.393 & 449.3 & 0.400 \\ \cline{2-10}  & Fault F2 & R632 & 498.1 & 0.370 & 477.1 & 0.384 & 467.9 & 0.388 & 461.2 & 0.390 \\ \hline \multirow{4}{*}{Zone 3} & \multirow{2}{*}{Fault F1} & R632 & 1400.1 & 0.300 & 490.0 & 0.800 & 438.2 & 0.840 & 432.5 & 0.840 \\  & & R671 & - & - & 440.1 & 0.380 & 438.2 & 0.390 & 432.5 & 0.380 \\ \cline{1-1}  & & F684 & - & - & 452.3 & 0.113 & 440.8 & 0.112 & 432.5 & 0.110 \\ \cline{1-1} \cline{2-10}  & & R632 & 1113.2 & 0.560 & 420.3 & 0.850 & 490.3 & 0.860 & 438.3 & 0.870 \\ \cline{1-1}  & & R671 & 1113.2 & 0.310 & 420.3 & 0.390 & 427.6 & 0.390 & 438.3 & 0.750 \\ \cline{1-1}  & & F684 & - & - & 439.5 & 0.110 & 427.6 & 0.119 & 438.0 & 0.120 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Relay and fuse currents, \(I\), and triggering times, \(t\), in the protection devices from the defined Protection Zones 1, 2, and 3 (see Figure 2, Figure 3, Figure 6, and Figure 10), in relation to the power supplied by the DG (1, 2, and 3 MW, representing 25%, 50%, and 75% of the photovoltaic installed power). Figure 5: Triggering time, \(t\), of protection relay R632 in Protection Zone 1 (see Figures 2 and 3), in relation to the power supply from DG. The currents detected by the relay when triggering were added to the graph in each case. Figure 8: Protection Zone 2 current-time (\(I\)-\(t\)) performance in case of a three-phase short-circuit at point F2, with 50% DG power (2 MW) at bus 633 (see Figure 6). Figure 9: Triggering time, \(t\), of the main feeder protection relay R632 in Protection Zone 2 (see Figures 2 and 6) for fault F1 downstream from the DG and fault F2 upstream from the DG, in relation to DG power supply. The currents detected by the relay when triggering were added to the graph in each case. Figure 11: Protection Zone 3 current-time (\(I\)-\(t\)) performance in case of a three-phase short-circuit at point F1, with 25% DG power (1 MW) at bus 652 (see Figure 10). Figure 10: Protection Zone 3 electric circuit (see also Figure 2), in which short-circuits in points F1 and F2 are indicated. Figure 12: Protection Zone 3 current-time (\(I\)-\(t\)) performance in case of a three-phase short-circuit at point F2, with 25% DG power (1 MW) at bus 652 (see Figure 10). Figure 13: Triggering time, \(t\), of the main feeder protection relay R632 in Protection Zone 3 (see Figures 2 and 10) for fault F1 upstream the DG and fault F2 downstream the DG, in relation to DG power supply. The currents detected by the relay when triggering were added to the graph in each case. In Table 2, the results obtained in relation to each of the analyzed scenarios are included. The fault currents and the protection relay tripping/triggering times are shown with regard to:  
* the Zone in which the fault was produced; and
* the penetration level (which is the ratio of the power supplied by the photovoltaic DG to the power demanded by the load, as indicated in the Section 2).