# Solutions to Increase PV Hosting Capacity and Provision of Services from Flexible Energy Resources
## 3 Simulation Results and New Frequency Adaptive _Pu_-Droop
### Frequency Adaptive PU-Droops for PVs and BESSs During Larger Under- and Over-Frequency Situations
Figure 8 shows the active power behavior of PV 2 and BESS as well as voltage behavior at PV 2 connection point during simulated under-frequency (49.4 Hz) events in Cases 5a, 7b (with different _PU_-droops, Figure 7 and Tables 7 and 8 ). From Figure 8 and Tables 7 and 8 it can be seen that PV 2 active power \(P_{\text{PV}\_2}\) is much less curtailed during under-frequency events in Case 7b with _PU_-droop 2 than with _PU_-droop 3. In addition, simultaneous change and increase in BESS 3 active power \(P_{\text{BESS}\_3}\) is smaller in Case 7b with _PU_-droop 3 than with _PU_-droop 2. These differences in \(P_{\text{PV}\_2}\) and \(P_{\text{BESS}\_3}\) behavior during under-frequencies are affected by different _PU_-droops as well as the PSCAD implementation logic presented in Figure 7b. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Case**} & **PV** & \multirow{2}{*}{**Load Level**} & \(P_{\text{PV\_2}}\), \(Q_{\text{PV\_2}}\), \(U_{\text{PV\_2}}\) & \(P_{\text{PV\_2}}\), \(Q_{\text{PV\_2}}\), \(U_{\text{PV\_2}}\) & \(P_{\text{PV\_2}}\), \(Q_{\text{PV\_2}}\), \(U_{\text{PV\_2}}\) & \(P_{\text{PV\_2}}\), \(Q_{\text{PV\_2}}\), \(U_{\text{PV\_2}}\) \\  & **Droop** & & **Steady-State, \(t\) = 25 s** & **49.4 Hz, \(t\) = 75 s** & **49.4 Hz, \(t\) = 95 s** * \\  & & & **(kW, kVAr, pu)** & **(kW, kVAr, pu)** & **(kW, kVAr, pu)** \\ \hline
2b & 1 & Low & 316, \(-\)150, 1.053 & 319, \(-\)150, 1.053 & 285, \(-\)150, 1.054 \\
7a & 2 & Low & 316, \(-\)150, 1.053 & 450, \(-\)150, 1.095 & 426, \(-\)150, 1.100 \\
7a & 3 & Low & 316, \(-\)150, 1.053 & 450, \(-\)150, 1.095 & 416, \(-\)150, 1.098 \\
5a & 1 & Low & 450, \(-\)150, 1.046 & 395, \(-\)150, 1.050 & 362, \(-\)150, 1.051 \\
7b & 2 & Low & 450, \(-\)150, 1.046 & 400, \(-\)150, 1.103 & 376, \(-\)150, 1.106 \\
7b & 3 & Low & 450, \(-\)150, 1.046 & 448, \(-\)150, 1.097 & 406, \(-\)150, 1.098 \\ \hline \hline \end{tabular}  
* Part of the load also at PV_2 connection point participates in demand response and disconnects from the LV network.  
\end{table} 
Table 7: PV 2 active (\(P_{\text{PV\_2}}\)) and reactive (\(Q_{\text{PV\_2}}\)) power as well as PV 2 connection point voltage (\(U_{\text{PV\_2}}\)) during larger under-frequencies (49.4 Hz) (Figures 1 and 2, Tables 2–6). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Case**} & **BESS** & \multirow{2}{*}{**Load Level**} & \(P_{\text{BESS\_3}}\), \(Q_{\text{BESS\_3}}\) & \(P_{\text{BESS\_3}}\), \(Q_{\text{BESS\_3}}\) & \(P_{\text{BESS\_3}}\), \(Q_{\text{BESS\_3}}\) \\  & **Droop** & & **Steady-state, \(t\) = 25 s** & **49.4 Hz, \(t\) = 75 s** & **49.4 Hz, \(t\) = 95 s** \\  & & & **(kW, kVAr)** & **(kW, kVAr)** & **(kW, kVAr)** \\ \hline
5a & 1 & Low & \(-\)93, \(-\)67 & \(-\)25, \(-\)67 & \(-\)25, \(-\)67 \\
7b & 2 & Low & \(-\)93, \(-\)67 & 144, \(-\)67 & 135, \(-\)67 \\
7b & 3 & Low & \(-\)93, \(-\)67 & 76, \(-\)67 & 76, \(-\)67 \\ \hline \hline \end{tabular}  
* Part of the load also at PV_2 connection point participates in demand response and disconnects from the LV network.  
\end{table} 
Table 8: BESS 3 active (\(P_{\text{BESS\_3}}\)) and reactive (\(Q_{\text{BESS\_3}}\)) during larger under-frequencies (49.4 Hz) (Figures 1 and 2, Tables 2–6).