IoT Network and Sensor Signal Conditioning for Meteorological Data and Photovoltaic Module Temperature Monitoring

The present paper describes the design, development, implementation and validation of an Internet of Things (IoT) network with sensors signal conditioning circuits for monitoring decentralized photovoltaic (PV) plants. The system intends to reduce costs of commercial dataloggers and sensing modules which require control and data storage using proprietary software. We applied our IoT monitoring network in three PV plants installed in Fortaleza and Maracanaú cities, Brazil, and in Cologne, Germany. The applied embedded solutions (namely, ESP 8266 and ESP 32) are based on free software and hardware and communicate with a Cloud server via Wi-Fi. A website, called Web Monitor, was developed in PHP for online and real-time data consultation in form of charts. The main objective of the proposal is to measure PV module temperature, providing data for the analysis of PV module’s efficiency and for fault detection in case of PV cells overheating. Solar irradiance, ambient temperature, relative air humidity and wind speed are also monitored, getting more data to analyze the effect of meteorological parameters on the PV module’s performance. The proposed system was designed in compliance with IEC 61724:1998 standard and the obtained charts are discussed in the results section considering different periods of the year. Finally, we validate the proposed temperature conditioning system with a commercial piece of equipment and a correlation of 0.9999 was achieved.