# Novel Internet of Things Platform for In-Building Power Quality Submetering
## 5 Evaluation and Experimental Results  
A complete platform to generate voltage sags and different voltage RMS values has been developed. The experimental platform is composed of a three-phase programmable AC power source, California Instruments 3001 iX [45], a three-phase electronic load, California Instruments Model 3091 LD, and a desktop computer used for configuring and monitoring the power system. An overview of the system is shown in Figure 13. This platform is part of the Smart-Grid test bench (SGTB) laboratory test bench for Smart-Grid research described in [43]. Figure 12: Publish to a channel field feed. Figure 13: Overview of the laboratory test bench. In our experimental test, the IoT PQ sensor has been connected between the AC power source and the electronic load, so that the IoT PQ sensor is continuously recording the voltage from the power source and current at the terminal of the electronic load, and, at the same time, uploading it to the Cloud (ThingSpeak platform). The advantage of using both programmable loads are that the reliability of the platform can be checked, as the registered and uploaded values by the sensor can be checked with values generated by the power source and consumed by the load, as they both integrate measuring devices. The AC programmable power system integrates a transient network analyzer and can also run several standardized PQ tests as voltage sags following IEC 61000-4-11. To have a controlled set of measurements, different voltage sags (according to the standardized tests provided by the power source) as well as different voltage RMS values, have been generated using the power source, to supply the electronic load, which has also been changed simulating different appliances. Simultaneously, the IoT PQ Sensor is measuring real voltage, current, energy as well as other power values and detecting voltage sags. To check the quality of the measurement, apart from the above equipment, two oscilloscopes have been connected for different purposes. The Yokogawa DL850E oscilloscope is recording the generated voltage waveforms at the terminal of the electronic load (i.e., the same voltage as the IoT PQ sensor is recording, and the RMS value can be also checked with it). Moreover, the Tektronix MDO3024 Mixed Domain Oscilloscope is recording the SPI communication signals between ADE7758 IC and the MCU (to check communication stability). The sensor uploads information from the V\({}_{\text{RMS}}\), I\({}_{\text{RMS}}\), Active Energy and Apparent Energy variables, which are obtained by aggregating several raw data points. Additionally, voltage sags are also on-time monitored and stored in the Cloud. All those data uploaded to the Cloud are accessible through an electronic device with an Internet connection. In fact, Figure 14 has been taken directly from the channel of ThingSpeak used for this experiment [50] using a search engine on a PC. Figure 14 (directly obtained from the ThingSpeak platform) shows the instant values as well as the time stamp of the upload data, given by ThingSpeak. Figure 14. (a) VRMS (b) IRMS uploaded in ThingSpeak. Figure 14a,b, represent the voltages at the terminals of the programmable load and the current flowing through it due to applied voltage respectively, representing an appliance. To ensure the reliability of the system, the prototype was subjected to a long-term monitoring test. For one hour, the IoT PQ sensor was monitoring the above variables under different supply voltages and load states, in total six different tests of 15 min duration each, and uploading data every 30 s to the Cloud (aggregating values between sendings). The V\({}_{\text{RMS}}\) was changed in two different voltage levels (220 and 230 V), and the current was also changed in three different levels (0.5, 0.8 and 2 A). Figure 15 shows the monitored voltage and current values taken by the sensor during long-term monitoring test 30 points were recorded in every test, all showing the stability of the sensor.