THE IMPORTANCE OF ENERGY RECOVERY TECHNOLOGIES FOR THE IMPLEMENTATION OF SMART SOCIETY AND SMART CITY CONCEPTS

An intelligently developed society is defined by a concept that integrates information technology in all its fields in which man is the direct beneficiary of this environmentally friendly process. Man is both the main actor and the direct beneficiary of the products and services of the intelligent society. This detail must be the determining factor for the development of any society from a classical to a smart one and here comes the concept of Human Informational Field (HIF) accompanies the human being in his interactions. But smart society is about connecting between people, systems, about sharing information and so we get to the Internet of things, or IoT a system of interrelated computing devices, mechanical and digital machines, objects, animals or people. The internet of things helps people live and work smarter, as well as gain complete control over their lives. Because IoT is a sensor network of billions of smart devices the problem of energy supply appears. Energy recovery or harvesting systems is a possible solution that could enable IoT nodes to scavenge self-sustaining energy from environmental sources. In this article we will review these systems and emphasize their importance in the development of smart society or smart city

TRANSIENT REGIMES OF THE THREE-PHASE POWER TRANSFORMERS

The transient regimes of a three-phase power transformer will be studied in this paper. The transient currents in the windings will be determined both analytically and by finite elements method (FEM). The no load and short circuit regimes will be considered. The current dependence of the instantaneous phase voltage and of the initial current value will be highlighted, by FEM. In order to determine analytically the transient currents, for inductances the analytical and FEM values will be used. The inductances are determined with FEM through the simulation of experimental tests. With FEM, the transient currents will be determined using transient analysis. Finally, the FEM and analytical results will be compared and discussed