A smart monitoring device of photovoltaic systems

Worldwide growth of photovoltaics (PV) is a continuous exponential curve, evolving from a niche market of small scale applications to a mainstream electricity source. Nevertheless, frequently varying output of PV caused by clouds movement and weather condition make it an intermittent and unreliable source when connected to grid. Connecting intermittent sources to grid introduces challenges in various technical aspects such as power quality, protection, generation dispatch control and reliability. In this context, the use of advanced forecasting of variable generation has become an essential strategy, allowing users to proactively manage the system’s output and maintain grid’s stability. Moreover, evaluation of performance in highly variable conditions is difficult without the use of precise data. When calculating the expected power yield from a system, there are many uncertainties in the estimation, but the solar resource estimate is the highest driver to the uncertainty that typically ranges from 5% to 17%. There are mainly two types of data from which we can take insights about the solar resource variable: modeled data sources and on-site measurements. Modeled data sources have measurement uncertainties in the 8 to 15% range. On-site measured data usually have a measurement uncertainty between 2 and 7%. Short-term quality measurements can be used to correct modeled data sources and improve their certainty. By comparison and validation of satellite based models, the uncertainty can be reduced by 2% to 6%. Short time on-site measurements can increase P90-probability of exceedance by over 5% and P99-probability of exceedance by over 10%. The solution consists of a portable meteorological station which is installed on the location of the photovoltaic system and centralized database with web based software interface. The data from the sensors can be used for: - Assessment of solar resource variable for prospective PV plants, therefore reducing the risk and increasing feasibility of the project. - Monitoring of existing PV systems, providing early fault detection and continuous evaluation of system performance, resulting with increased system availability and increased performance - Evaluation of soiling - Evaluation of system degradation rate - Evaluation of system performance - Optimization of the technical specification of system components by simulation of power yield The Macedonian company has developed a functional prototype and currently needs a partner that will test and evaluate the solution. The feedback will be used to improve and bring the solution to a higher TRL. Technical cooperation agreement is possible, enabling joint further development of the technical aspects and later exploitation of the improved solution for the benefit of both parties.