The course presents a wide view on the emergent aspects in the evolution of the electricity systems, with the on-going transition towards a growing utilization of electricity in many applications. The concept of “smartness” in electricity and energy systems is related to the new ways in which a system can operate and also interoperate with other systems (e.g., transportation) for assuring a socially desirable performance in terms of sustainability (energy efficiency and environmental impacts reduction), economic efficiency and affordability, electricity security and reliability. The course starts from an overview on the structure and operation of modern and future electrical networks (smart grids), with a special focus on Low-Voltage and Medium-Voltage distribution and utilization systems. A conceptual model of the smart grids is presented, in which various aspects (technologies, energy, data, markets, etc.) are analysed, along with their interactions, in a comprehensive way. Some of the most important “smart functions” in the emerging operation of the electricity distribution systems are illustrated, highlighting the concept of interoperability of various systems and actors over the smart grid, e.g., electric vehicles, prosumers, network operators, distributed energy resources (DER), etc. The impact of the DER introduction in the electrical networks is studied by addressing theoretical aspects and application examples concerning distributed generation, distributed storage and demand response. On the local system side, the course deals with the structures of the power electronic conversion systems, including both the source-side converters and grid-side converters. To better understand the power electronic conversion concepts and their application, an experimental activity is carried out in the laboratory of the Energy Department. Some applications are solved through numerical calculations carried out in the computer laboratory.

The student who passes the exam will gain skills for interacting with the operators of the electrical system by using the correct terminology and by showing appropriate knowledge to discuss the basic issues concerning smart grid and distributed energy resources. The student will also become aware of the technological evolution in progress and of the impact of this evolution on the present and future smart electricity systems. The minimum objectives to be reached as learning outcomes include: - ability to use the correct terminology in addressing the problems concerning smart grid applications; - ability to interpret the problems concerning the introduction of distributed energy resources in the smart grids.

The prerequisites include the knowledge of matrix calculations, complex numbers, basic electrotechnics (direct current circuits, single-phase and three-phase alternating current circuits), and the principles of operation of the electrical machines (synchronous machine and transformer).

PART 1 (30 hours): Smart grid architecture and emerging scenarios Probabilistic models of generations and loads. Adequacy of the generation to cover the demand. Adequacy indicators. Structures of electrical transmission and distribution systems. Emerging paradigms (smart grid, distributed energy resources, virtual power plants, microgrids, multi-energy systems, prosumers). Technical evolution of the grid infrastructures. Active electrical networks. Demand Side Management. Smart metering concepts. Advanced Metering Infrastructure (AMI). Notes on the energy markets. Evolution of the tariff structures towards real-time pricing. Smart grid architecture model (SGAM). Smart operation of electrical distribution systems. Smart functions and interoperability of different systems. PART 2 (20 hours): Power electronics for smart grid connection Structures of power electronic conversion systems for distributed generation: grid-side converters and source-side converters. Examples of distributed energy sources (micro-turbines, micro-hydro, wind generators, photovoltaic panels and fuel cells). Grid-side converters: topologies (single-phase and three-phase inverters, output filters); operation in parallel with the grid as current-controlled voltage sources and the corresponding control schemes; island operation or in parallel with a micro-grid as voltage-controlled voltage source with droop control. International standards for the connection with the grid of power converters for distributed generation (IEEE 519, UL1741, IEC 61000-3-12, VDE 0126-1-1). Source side converters: AC/DC converters for electrical generators used by wind turbines and micro-turbines; DC/DC power converters for photovoltaic panels and fuel cells along with control schemes. PART 3 (30 hours): Distributed energy resources (DER) Distributed energy resources (DER). Limits to the DER diffusion. Island operation of a portion of the distribution network. Microgrids. Combined production (cogeneration and multi-generation). Black box analysis. The Energy Hub matrix model. Impact of the combined production on smart grids. The role of the environment. Local and global emissions. Emission factor model. Emission balances. Indices of emission reduction. Storage applications in the smart grid area. Power vs. energy. Drivers to storage development. Parameters of the storage systems. Objectives of the use of storage in the electrical systems. Storage in the Energy Hub model. Standards on storage. Connection schemes. Power-to-X. Storage systems for primary and secondary frequency regulation. Evolution of the regulatory framework and of the standards for smart grids. Grid codes. Active and passive users. Operating modes for the grid-connected local generation. Notes on the Standards CEI 0-16 and CEI 0-21. General scheme of the system protection with possibility of islanding operation. Scenario studies with local generation in smart distribution systems. Capability limits of the generators with transformer-based or converter-based interfaces. Capability curves with storage. Voltage control with distributed generation. Objective function and constraints for voltage control. Fault ride-through capability curves and limits for low voltage and medium voltage systems. Notes on the protection system with voltage and frequency relays. Electrical load representations. Load duration curves. Macro-categories of users. Active and reactive power profiles. Demand Side Management principles. Evolution of the tariff structures towards real-time. Demand response (DR). Incentive-based and price-based DR programmes. Costs and benefits for DR. DR baseline. DR performance metrics. Notes on demand flexibility and on the new generation of smart meters. Grid integration of electric vehicles: Vehicle to Grid and Grid to Vehicle. Charging stations and parking lots. Notes on the traffic models. Framework for studying the grid integration of electric vehicles. Operation and planning aspects. Optimization of the smart grid operation with storage systems and EVs.

The contents of the course are presented during the lectures, with possible numerical examples. The course includes activity held in the computer laboratory, as well as experimental activity, in particular: - 15 hours in the computer laboratory: scenario studies on the impact of the distributed generation in the distribution system. Analysis of a distributed generation mix with various scenarios of diffusion of the local generation. Integration of distributed energy resources in the distribution networks. - 1.5 hours of experimental activity: assessment of the performance of a 15 kVA front-end three-phase converter da 15 kVA with LCL filter on the grid side, DC-supplied from a battery emulator.

The material (slides and handouts) used during the lectures and course activities will be available on the web portal. There is no commercial book covering the contents of this course. Reference books: Nick Jenkins, Ron Allan, Peter Crossley, Daniel Kirschen, Goran Strbac, 'Embedded generation', IET (ISBN 978-0-85296-774-4), 2000. Remus Teodorescu, Marco Liserre, Pedro Rodriguez, “Grid Converters for Photovoltaic and Wind Power Systems”, Wiley 2011, ISBN: 978-0-470-05751-3. D.N. Gaonkar (ed.), Distributed Generation, Intech (ISBN 978-953-307-046-9), 2010. Freely available at the web address http://sciyo.com/books/show/title/distributed-generation.

Modalità di esame: Prova scritta (in aula); Prova orale obbligatoria; Prova orale facoltativa;

Exam: Written test; Compulsory oral exam; Optional oral exam;

... In the two calls of the winter exam session, the exam consists of a written test of duration 2 hours. For the part “Power electronics for smart grid connection”, the written test has closed responses and the score is one third of the total score. For the other parts, the students have to respond in a written way to a number of questions referring to the entire course programme, with possible inclusion of numerical exercises. The results of the exam will be communicated through the web portal. The students will have the possibility of viewing the corrected test in the date communicated by the professor responsible of the course, with possible oral discussion aimed at clarifying specific aspects in case of unclear responses (not in case of incorrect responses). In the other sessions, there is a written test for the part “Power electronics for smart grid connection” (with duration of one hour, prepared in the official dates of exam), while for the other parts the exam is oral (with exam dates agreed with the Commission during the scheduled exam periods). The student can access the oral exam only if the score obtained in the test of the part “Power electronics for smart grid connection” is positive (at least 50% of the maximum score of the test). The score of the written test is one third of the total score. The oral colloquium includes one question for each one of the other parts of the course. The final score refers to the knowledge and ability level reached on the different topics of the course programme. The rationale for this type of exam is that the written test refers to basic aspects and components for power electronics conversion, while the other parts deal with system-related concepts that require elaborating wider responses. The laboratory activities carried out during the course have no dedicated score; the discussion on the outcomes of the laboratory activity may be part of the written or oral exam. The time limit for completing the written test is indicated on the blackboard at the beginning of the period. To access the exam room, each student must exhibit a valid document with photo. During the test the Commission identifies the location of the students. During the test the students may exit from the exam room only if they withdraw from the test or from delivering the final writing. In case of withdrawal the text of the exam has to be given back with the indication of the student’s name and surname on the first page and with the writing “WITHDRAWN”. When the writing is delivered, the text with the indication of the student’s name and surname must be included in the delivered material. During the written exam, the students may use only clean paper, pen and pocket calculator. Personal computers, laptops, tablets, phones or equipment for taking photos are not allowed. The course material, clothes and the personal belongings must not remain on the work plan, nor under the desk, and must be located in a position in which the contents relevant to the exam cannot be reached. Contacting other persons of material is not admitted. If a student is found with any material not allowed in accessible location, or contacting other persons, his/her test is immediately annulled and the student will have to leave the room. Any question concerning the exam must be addressed to a member of the exam Commission. In case the question is of general interest, a member of the exam Commission will inform all the students participating in the exam. The exam is passed if all the minimum objectives indicated in the section "Expected learning outcomes" are reached. Failure in reaching one or more of the minimum objectives determines the non-passed exam evaluation.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.