## 5 Methodology Validation
### Scenario 1: Solar Photovoltaic  
This scenario consists of a MG with the capacity to supply the critical loads. The installed capacity of this is 1.4 MW, and is distributed in two PV arrays, of 700 kW each. Each array contains 1540 PV panels with a capacity of 455 W.  
Medical Services and Biology have back-up generators of 20 and 1250 kW, respectively. These generators have been in service during emergencies and their behavior has been adequate. However, the other loads do not have back-up generators, nor do they have smart meters for telemetry. For this reason, a load study was conducted. A capacity around of 100 kW is necessary to supply this load.  
Table 4 shows the configuration and technical parameters of the PV arrays. The PV array was designed considering variables such as capacity per PV panel, quantity of installed panels, available area, and location. This table shows that the configuration proposed could be installed in the library's parking, known as White Area (WA) and the Biology parking lot (BP). Only a 41% and 66% of the available area is used, respectively, with the capacity of 700.7 kW each one and a total installed capacity of 1.4 MW.  
For the simulation, three profiles of irradiance in Mayaguez were considered, analyzing a database of ambient weather with information of one year [33]. For the test, three different days were selected: one with major solar radiation, one with minor solar radiation, and one with average solar radiation. The profiles of solar radiation used are shown in Figure 14. The green curve represents the day with major solar radiation, the orange curve represents the day with minor solar radiation, and yellow represents the curve of average solar radiation per year in Mayaguez.  
The results shown in this section were obtained using the average solar radiation. The behavior was constructed using an average for each five minutes. The analysis for the solar radiation average per year was done.  
In Figure 15, the colors blue, orange, and gray represent the phases A, B, C, respectively. We can see that the MG contributes to improve the voltage profile and allows that the voltage maintain between the limits of regulation.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**PV Configuration**} & \multicolumn{3}{c}{**Location**} \\ \hline
**Capacity [W]** & **Quantity** & **Area PV Maintenance [m\({}^{\star}\)]** & **Total Area [m\({}^{\star}\)]** & **P [kw]** & **Name** & **Available Area [m\({}^{\star}\)]** & **\% Used Area** \\ \hline
455 & 1540 & 3.31 & 5103.21 & 700.7 & WA & 12,576.9 & 41\% \\ \hline
455 & 1540 & 3.31 & 5103.21 & 700.7 & BP & 7765.72 & 66\% \\ \hline \hline \end{tabular}
\end{table}
Table 4: PV Configuration and Used Area.  
Figure 14: Solar Radiation in Mayaguez.  
On the other hand, the solar panel system at the university contributes to saving energy consumed from the main grid. The percentage of contribution per day is showed in Table 5, where SS represents the consumption of the entire university in steady state and CL represents the consumption of the critical loads. PV systems do not negatively affect the system, the voltage profile stays within the permitted range, this is reflected in the voltage profile graphs (Figure 15). One disadvantage with this test scenario is that the solar panel system cannot operate in islanded mode because it needs a system as a reference.  
According to the MG regulation in Puerto Rico, the scenario met with the requirements. The regulation establishes that the energy produced for the MG should be at least seventy five percent (75%) of the total energy produced by MG ( Regulation 9028. Article 3. Section 3.03 [32]). Analyzing cost per kWh of the PV system, savings in the first year could be USD 408,800, considering that the expected energy production in the first year is 2,555,000 kWh. This saving is considering that currently the cost per kWh of the authority is approximately USD 0.21 and the cost per kWh of PV system is approximately USD 0.04.