# Software Integration of Power System Measurement Devices with AI Capabilities
## 4 Laboratory and Field Tests
### PV Plant Integration Testbed and Results  
The designed framework was tested for the local monitoring and diagnosis of two PV plants. As shown in Figure 10, the selected PV plants are located near the town of Pozoblanco, Cordoba, Spain, and are approximately 4.1 km apart. Measuring equipment was installed in each of the Transformation Centers (TCs) so that the entire plant could be monitored by sectors rather than just being monitored at the grid injection point, as is typically done with other types of DERs. This decision would enable sector-by-sector analysis of the plant. The synchronization of the measurements that took place at the different plants--and, of course, at the different TCs--is therefore essential. A National Instruments (NIs) device was placed in each TC; either an NI compactRIO-9054 (cRIO) or an NI compactDAQ-9185 (cDAQ). These devices are highly configurable, both in terms \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Grid**} & \multicolumn{3}{c}{**Mean**} & \multicolumn{2}{c}{**Median**} & \multicolumn{2}{c}{**Standard**} & \multicolumn{1}{c}{**Deviation**} \\  & & **PQM** & \(\upmu\)PMU & **PQM** & \(\upmu\)PMU & **PQM** & \(\upmu\)PMU \\ \hline
200 \(\Omega\) & L1 & 234.844350 & 234.868278 & 234.857178 & 234.871002 & 0.314561 & 0.289386 \\  & L2 & 233.636106 & 233.665480 & 233.628845 & 233.692093 & 0.292432 & 0.266356 \\  & L3 & 233.859748 & 233.874439 & 233.909607 & 233.896378 & 0.249912 & 0.254858 \\ \hline
100 \(\Omega\) & L1 & 229.208301 & 229.203424 & 229.206848 & 229.233902 & 0.345478 & 0.308342 \\  & L2 & 228.065891 & 228.078867 & 228.118896 & 228.158340 & 0.420111 & 0.409235 \\  & L3 & 228.204456 & 228.208538 & 228.259277 & 228.283234 & 0.348560 & 0.322407 \\ \hline
500 \(\Omega\) & L1 & 220.302708 & 220.182244 & 220.292664 & 220.214401 & 0.239520 & 0.267840 \\  & L2 & 219.254813 & 219.162677 & 219.274902 & 219.166412 & 0.191814 & 0.197216 \\  & L3 & 219.133311 & 219.015484 & 219.204712 & 219.071167 & 0.245116 & 0.260246 \\ \hline \end{tabular}
\end{table} 
Table 4: Voltage comparison. Figure 9: Voltage measurements of a PQM PQube3 vs. \(\upmu\)PMU. of software and hardware. On the one hand, the cRIOs were configured to record synchrophasors, effectively functioning as PMUs. To achieve this, a GPS module was added for synchronization. On the other hand, the cDAQs were set up to record RMS voltage and current measurements, similar to a PQM. The cDAQs installed at TC1 and TC2 in plant 1 (Cruz del Doctor, 4 MW), and the cDAQ at plant 2 (Cabeza Oliva, 1.8 MW) were also equipped with an analog input module to record irradiance measurements from a pyranometer grid, as shown in Figure 10.  
The objective was to measure the entire production of the two PV plants by capturing data simultaneously from all TCs. In each plant, a PMU was installed in one TC, while cDAQs were placed in the remaining TCs. The devices within each plant were connected via a dedicated Ethernet line using the Time-Sensitive Networking (TSN) standard, which ensures synchronization levels of the order of 1 \(\upmu\)s [59]. In this setup, the PMU acts as the Master, while the cDAQs function as Slaves. Together, all devices in the same plant form a single conceptual measurement unit known as an extended PMU (ePMU). The cDAQs transmit their measurements to the Master PMU, which then forward these measurements to the framework exposed in this paper via the IEEE Std. C37.118.2. Figure 11 illustrates the data flow. This strategy aims to ensure a rapid response to eventsm as well as the joint management of energy produced by multiple plants. To achieve this, it is crucial to have the  
Figure 11: Framework data flow at two PV plants. Figure 10: PV plants located in Pozoblanco, Cordoba, Spain. measurements from both plants synchronized with each other. Figure 12 shows the frequency recorded at the two plants. As can be seen, both records show the same variations, which are likely due to the behavior of the electricity grid, showing that this grid parameter is not affected by the operation of the PV plants.