Abstract:

The IDEA Research Group has developed a new method that improves the analysis performance of Stand-alone photovoltaic (SAPV) systems with batteries as the storage element and with charge regulators without Maximum Power Point Tracker, keeping in mind the idiosyncrasy of these systems. Moreover, and in order to aid in the monitoring and the analysis of performance of SAPV systems, the IDEA Research Group has developed a monitoring system for SAPV applications based on a graphical user interface (GUI) that allows users to interact and check the operating status of the SAPV systems through graphical charts and visual indicators. Moreover, it has been developed a web application where the collected and derived parameters are shown in real time in order to provide an online monitoring. The monitoring system controlled by an application developed in LabVIEW manages to provide data in real time which allows the possibility of remote supervision and system fault detection if any. In this way, it can be used by scientific and engineers in order to analyse historical data and to asses the performance and reliability of the SAPV systems. Moreover, the web application here developed can not only highlight interesting technical aspects about the monitoring of stand-alone photovoltaic systems, but it can be also used for educational purposes too.

Once the investigation tasks have been achieved, the web application has been slightly modified in order to use it for educational purposes, in particular in a post-graduate Master in Renewable Energies that is offered in Jaén University. In this way, three SAPV systems installed in the Polytechnic School of Jaén University are being monitorised and historical data are presented online and in real time using a web interface. The main function of the website is to provide the student the daily evolution of all monitored parameters, as well as the daily value of the derived parameters of analysis. All this through the automatic graphical representation system that have been implemented. Moreover, it is offered the possibility of downloading the figures and text files, relating to the monitored variables and parameters of analysis included in the methods of analysis considered as complying with the format proposed in the standard IEC 61724. In that way, the student can make its own offline analysis. Furthermore, it has also been not only enabled the student to download the files obtained from the monitoring system and in this way, the latter can manage to develop its own performance analysis and compare it with the results given in the web, but each student can also define different load profiles during a determined period of time in order to study the effect of the former on the SAPV system performance.

The different load profiles are managed through a load box connected to each SAPV system. This loads box consists of four power halogens. All of them can be switched on/off in order to provide different hourly discharge currents ranging between 0,90 and 13 A. The student through the web application will introduce the daily load profile to be studied. Each student is given a five-day period to set its load profile and develop its study.