Abstract

Energy efficiency is a key challenge to build a sustainable society. It can be declined in variety of ways: for instance, from the reduction of the environmental impact of appliances manufacturing, to the implementation of low-energy communication networks, or the management of the existing infrastructures in a smarter way. The actual direction is the integration of different energy systems with a common management scheme with the aim of harmonizing and integrating different energy systems. In this context, smart cities already envision the use of information communication technologies (ICT) to smartify objects and services, connecting people and machines. An important enabling technology for smart cities is certainly the Internet of Things (IoT). Both smart cities and IoT have been extensively investigated over the last few years, under the influence of European funded projects as well. Smart cities apply communication and networking technologies, very often using the paradigm of IoT, to address relevant issues like traffic congestion, population growth, crowding, and others, besides implementing innovative services, modernizing existing infrastructures, e.g. smart mobility. IoT greatly helps in monitoring and better managing energy consumption as well, realizing smart homes, smart buildings and smart grids. For what concern the power grid, in fact, the direction is to harness IoT technologies to improve flexibility, easiness of use and, ultimately, energy efficiency while preserving stability and safety. Today the electrical grid is facing deep changes, mostly caused by the intensive deployment of Distributed Energy Resources (DER) based on renewable sources such as photovoltaic plants or wind farms. Managing such heterogeneous active distribution networks (ADNs), represent one of the most important challenges to be faced in the future of energy systems. The integration of active elements into the grid is challenging because of both the great potential they bring in energy production and the hazard they may represent if not properly managed (e.g. violation of operational constraints). ADN implementation relies on the deployment of high-performance real-time monitoring and control systems. It is well accepted that the phasor measurement units (PMU) are one of the most promising instruments to overcome many problems in ADN management, as they support a number of applications, such as grid state estimation, topology detection, volt-var optimization and reverse power flow management. However, classic PMUs are conceived to measure synchrophasor in transmission systems, while the distribution ones have very different characteristics and, in general, different needs. Therefore, tailoring the characteristics of the new-generation PMUs to the needs of the ADNs is currently very important. This new kind of PMU must address few important design challenges: 1. improved angle measurement capabilities, to cope with the smaller angle differences that distribution grids exhibit; 2. low cost, to promote an extensive deployment in the grid. These two requirements are clearly in opposition. In this dissertation, a low-cost PMU design approach, partially influenced by IoT ideas, is presented.