Electricity is one of the most crucial discoveries in human history. It offers comfort, luxury, encourages invention and is of enormous importance to our daily life. However, the evolution of their transportation and generation systems cannot keep pace with their increasing demand. In some regions of the world we have already reached critical points where the imbalance between supply, demand and distribution is causing immense direct and collateral damage. The areas affected by these problems seem to be getting bigger and bigger. These infrastructures cannot withstand future demands, especially as the integration of renewable energies and the growing trade in these various energy sources are expanding.
The main enabler of all these possibilities are transformers, which are located on all branches of the power line. However, the majority of all transformers used are already at the end of their life cycle or are about to do so. This means that the goals and visions for expanding our electrical system cannot be achieved now or in the future if no significant changes are made to it. Most transformers already have an operating life of 30 to 40 years, and the ongoing integration of renewable energy systems leads to ever greater and more frequent fluctuations that endanger the stability of the system. This problem is all the more important because replacing defective and defective transformers is an expensive and time-consuming affair, and the replacement can take up to 2 years.
Knowing about this problem and working on it has led to the development of a so-called new "Smart Grid" that can withstand higher future demands and at the same time offer a more stable and robust infrastructure. A task that has to be done "on the fly", ie renewal of a system that is in continuous operation. Understandably, this is a difficult endeavor where even the smallest mistake can lead to a cascade reaction with catastrophic results. Therefore, monitoring of the most critical components, namely the transformers, is a necessity in this structure.
When it comes to the operation of a transformer, the insulating oil is the most important element that ensures its long service life. However, over time it becomes contaminated with undesirable substances that affect its functionality. The analysis of these impurities and their concentrations can provide information about the service life and the aging of the transformer itself and at the same time provide important data about the electrical insulation properties, which ensure the correct operation of the transformer. The standard procedure for obtaining the aforementioned knowledge of the oil is nowadays to carry out selective and sporadic laboratory analyzes of probes taken from transformers in operation. A practice that produces results that represent a condition of the oil far removed from its actual state of use. The lack of integrated monitoring options means that the oil is only examined in the laboratory after 5-10 years of initial commissioning, if at all, and at intervals of 1-2 years when the age of the transformer has reached a critical condition.
Based on this situation and taking into account the current disadvantages of the process, the aim was to develop a sensor that is able to record data about a transformer in operation in real time without impairing or falsifying its functionality. The recorded values should be able to provide the operator of the transformer with all the necessary information in real time so that he can react as quickly and effectively as possible to changes in his products.
