## 3 Results
### Use of the Developed Application in the Analysis of Some Parameters of Two PV Plants
It can be seen that, in the case of plant 1, the value of the grid voltage measured at its PCC is higher than at the second plant. Even though plant 1 is smaller in size or power rating, the value of the \(V_{ac}\) voltage will depend primarily on the state of the grid at that point, which will be conditioned by all the elements connected to it, and not only by the PV installation. It can be also observed that there are days in which lower voltage values were registered, and occasionally, cases of overvoltage values. The variability throughout the year is not very significant, although a slight increase can be observed during the summer months. Figure 17: Grid voltage values (\(V_{ac}\)) measured every 5 min on phase 1 by inverters 1 (**a**) and 10 (**b**) of plants 1 and 2 respectively during the period 1 November 2020 to 4 July 2022. The maximum, minimum and average voltage values have also been determined for the entire period analysed, but in this case for one of the 288 moments of the day in which the data is recorded, i.e., every 5 min. The results obtained can be seen in the graphs in Figure 19, which show the \(V_{ac}\) values in phase 1 measured by inverters 1 (a) and 10 (b) of plants 1 and 2, respectively. It can be seen in this case that the overvoltage values recorded and shown in the graphs in Figure 16 occur in this case at times of the day when the PV plants are not in operation. If these overvoltage values had occurred during production hours, the inverter would have interrupted the injection of energy until the voltage values had returned to the established ranges. Furthermore, the graphs in Figure 19 show very clearly that the grid voltage value shows a slight increase during the hours when the PV plants are in operation. This behaviour is more significant in the case of installation 2 (Figure 19b), as already shown in Figure 17, as it has already been indicated that it is larger. Although the \(V_{ac}\) voltage values are within the margins accepted by the standards, the grid at these points will have a hosting capacity, so that if the power values of the installations increase, so would the value of the grid voltage, so that the installed power could never be greater than that which would cause the value of the \(V_{ac}\) voltage to exceed the value recommended by the standards. These examples show that, once the data values measured by the different elements of the PV plants have been correctly ordered and stored using the database management system developed, it is possible to quickly analyse the measured data to obtain information on both the behaviour of the plant elements and their influence on the electricity grid in  
Figure 19: Average values (brown) and the difference between daily maximum and minimum (blue) for the period from 1 November 2020 to 4 July 2022 of the \(V_{ac}\) grid voltage measured in phase 1 by inverter 1 of plant 1 (a) and inverter 10 of plant 2 (b), in each of the 288 daily records, with a frequency of 5 min. Figure 18: Average values (brown) and the difference between daily maximum and minimum (blue) of the \(V_{ac}\) grid voltage measured on phase 1 by inverter 1 of plant 1 (a) and inverter 10 of plant 2 (b), in the period from 1 November 2020 to 4 July 2022.  
order to make decisions regarding their O&M for the benefit of both the plant owners and the grid users.