## 3 Results and Discussion
### Analysis of the Relationship between the Grid Voltage and the Power Generated by the Inverters
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Max \(V_{AC}\) Intercept** & **Min \(V_{AC}\) Intercept** & **Average \(V_{AC}\) Intercept** & **Difference between Max and Min** \\ \hline PV Installation 1 & 236.83 & 232.15 & 234.89 & 4.68 \\ PV Installation 2 & 243.56 & 233.40 & 237.89 & 10.16 \\ PV Installation 3 & 219.78 & 215.23 & 217.47 & 4.55 \\ PV Installation 4 & 237.83 & 223.33 & 236.03 & 5.50 \\ PV Installation 5 & 240.33 & 236.76 & 238.80 & 3.57 \\ PV Installation 6 & 236.81 & 233.54 & 232.89 & 3.27 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Maximum, minimum, and average values of the Y-axis-intercept obtained by correlating weekly over the three-year period the values of the grid voltage versus the power generated in the PV installations. intercept only varies by around 3 V during the entire period analysed, and the slope values found are among the lowest. The network in which installation 3 injects (located in a rural area) would also be among the most resilient, in which the slope is also one of those with the lowest values, together with lower values of the \(Y\)-axis intercept. It can be seen in Figures 16-21 that the slope values found vary from week to week. Except in the case of installation 2, where this behaviour is not observed, in the rest, it can be seen that during the summer months, the slope values are lower than those found during the winter months, indicating that the network is less resilient to PV production during the winter months. Although PV production is lower during the winter months, in summer, the maximum PV production coincides with the hours of highest temperature, and therefore, of highest electricity demand for air-conditioning, which in the geographical area analysed in this work represents a significant percentage of the electricity demand at those hours of the day [45], which could contribute to the fact that at those hours of highest production the voltage values increased less. [PERSON] et al. [31] have already indicated that some impacts of distributed generation can be positive, for example, where PV generation is closely correlated to air-conditioning loads and hence reduces the peak network currents seen in the network. It is obvious that the impact of the PV installation on the grid voltage value will depend on the one hand on the relative size and location of distribution generator (DG). But in addition, the specific pre-existing situation at each point in the network in terms of the connected loads nearby, their distribution topology and the methodology applied for voltage regulation are also influencing [43]. DG connected to the distribution network can significantly influence the aggregated impacts of all components in the grid [31]. If the grid impedance is higher, the PV output will have a greater effect and higher slope values will be obtained. If the voltage value prior to the injection of renewable production is low, the available margin for more renewable generation capacity is higher. It was observed that with the parameters recorded by the inverters themselves, it is possible to assess how this impact is being, without the need to include additional measurement systems. With the values of slopes and \(Y\)-axis intercepts found, it was also possible to estimate the maximum PV production capacity that each phase would admit in each of the grid points studied without exceeding the maximum values of the grid voltage indicated by the regulations, to avoid affecting consumers close to the PCCs with overvoltage values. This would make it possible to know the hosting capacity of the network in terms of the limit set by this parameter. For this purpose, the procedure for installation 3, shown as an example, is plot in Figure 23. In this Figure 23, the most unfavourable regression line is shown in green, the mean regression line in black and the most favourable line in yellow. In red are the maximum voltage values permitted by the standards.