# Software Integration of Power System Measurement Devices with AI Capabilities
## 4 Laboratory and Field Tests
### Laboratory Testbed and Results  
The designed software was implemented and tested in the laboratory using four units of the most demanding commercial electrical monitoring devices. Two Powerside PQMs, specifically the three-phase PQube3 model and two \(\upmu\)PMUs of the same brand, were used as measuring equipment. The \(\upmu\)PMUs generate the measurements shown in Section 2.2 for each phase, plus some power measurements that are only displayed on the device and are not transmitted. The PQM, on the other hand, generates more than 3000 values among power, energy, harmonics, and other PQ measurements. As described in Section 3.1, \(\upmu\)PMU uses, as usual, the IEEE Std. C37.118.2. It can be configured to the different existing versions, and in this case, the 2011 version was picked. In the case of PQMs, they use Modbus TCP/IP. The four devices were connected simultaneously to the TSDB, storing the data they generate in real time. Both the TSDB and the Telegraf agent were located on one PC, while OpenPDC ran on another PC, both within the same local network. Grafana monitoring software was also in the same computer where the TSDB was hosted. Figure 4 shows how the equipment was placed in the laboratory, while Figure 5 shows the data flow. Figure 6 shows a dashboard in Grafana where the most significant measurements collected by the PQMs are represented in real time. In the upper-left corner, the PQM for which the data are to be displayed is selected, whereas in the upper-right corner, the time and date are selected. A similar dashboard was created for the \(\upmu\)PMUs. In these tests, the equipment was conveniently compared in pairs. First, we compared the equipment of the same type with each other, followed by comparisons between the  
Figure 4: Experimental testbed in the laboratory. Figure 5: Experimental test data flow. Figure 6: Real-time monitoring of a PQM (PQube3) analyzer with Grafana dashboard. PQMs and \(\upmu\)PMUs. Both PQMs and \(\upmu\)PMUs offer high measurement quality, but due to their differences in technology, comparing them is challenging. PQube3 analyzers are class A, while a \(\upmu\)PMU is guaranteed to have a Total Vector Error (TVE) of \(\pm 0.01\%\). PQube3 collects data every second, whereas for the \(\upmu\)PMU, a sending rate of 10 ms was chosen. Figure 7 displays two tests in which measurements were collected at the same point by two PQM PQube3s over a duration of 5 min. Although all available measurements were collected, only the frequency is shown. In the first test (Figure 7a), data were collected from an ideal source, in particular from a single-phase Agilent 6811B source. The second test was performed by collecting data from the laboratory grid on a connected load of 200 \(\Omega\). In both cases, the measurements appear similar and synchronized, which is particularly evident in Figure 7b, where changes in the grid frequency have been accurately captured. PQM measurements are timestamped upon arrival at the TSDB. A limitation of the test is that the measurement devices were located in close proximity to each other, specifically within the same LAN network. Nonetheless, the possible delay added by placing the equipment farther apart would be in orders of magnitude much smaller than  
Figure 7: AC power source and grid frequency measurements using two PQM PQube3s. one second. The delay added in Wide Area Networks (WANs) will also remain, regardless of the software. Figure 8 presents data from a PQM PQube3 and a \(\upmu\)PMU under the same conditions as those shown in Figure 7b.The most significant difference between the measurements of both devices is the number of samples per second, with the second device sampling at a rate 10 times higher than the first. Even so, the central tendency recorded by the PQM PQube3 and by the \(\upmu\)PMU, as well as \(\sigma\), are similar, meeting up to the third decimal place. The results obtained for a set of tests are shown in the Table 3. Under the same conditions, only the load was changed.