


Politecnico di Torino  
Academic Year 2015/16  
01APPNC Electric power distribution and utilization 

Master of sciencelevel of the Bologna process in Electrical Engineering  Torino 





Subject fundamentals
The course belongs to the learning area of Electroenergetic systems and deals with the details of the analysis of components and operation of the electricity distribution systems at Medium Voltage and Low Voltage. The course contents include the structures of the distribution systems, the characteristics of the protection devices, the study and application of the distribution system analysis and optimization techniques, the study of power quality and continuity of supply in distribution networks, the effects of the diffusion of gridconnected distributed generation and distributed resources, and the optimal distribution network planning.

Expected learning outcomes
The course contents aim at providing knowledge and understanding skills, in a specific way or integrated with the contents of other courses belonging to the same learning area, with reference to the following points:
 structures and solutions for electrical energy distribution;  selection and coordination of the protections in electrical installations;  modelling and numerical solution of distribution networks in normal operation and in case of faults;  distribution network optimization;  integration of the distributed generation and distributed resources in the distribution systems;  power quality and reliability of electricity supply;  interactions of the electroenergetic systems with the environment. On the application side, knowledge and understanding aspects refer to the ones indicated for the Electroenergetic systems learning area. More specifically, the minimum objectives of the course include:  selection and interpretation of the operational characteristics of the switching and protection systems for DC and AC distribution systems;  defining the models of the components used in distribution systems and writing the equations describing the distribution system operation;  applying at least one numerical technique for solving each of the problems of distribution system analysis, reconfiguration and planning;  interpreting the aspects of reliability and power quality in the electrical distribution networks;  understanding the main concepts referred to distributed generation and distributed resources and their grid connection. 
Prerequisites / Assumed knowledge
Knowledge and skills required as prerequisites for attending the course refer to:
 basic notions of matrix calculations and electrical circuit analysis;  elements of probability theory and statistics  structure of the electrical systems for electrical energy production, transmission and utilization;  components and devices for operation and protection of Low Voltage systems;  behaviour of electrical machines in normal and fault conditions;  basic programming (e.g., Matlab);  use of basic text editing and spreadsheet tools. 
Contents
The contents are composed of four main parts, reported below together with the indicative number of hours for each part.
PART I – Distribution system structure, analysis and operation (40 hours): Network structures, component models, electrical load classification, aggregate residential loads, uniformly distributed loads, thermostatcontrolled loads and cold load pickup; application examples. Network representations, loadflow calculations in radial and weaklymeshed networks, loadflow of unbalanced threephase systems, probabilistic loadflow. Classification of the optimization problems, optimal reconfiguration in normal conditions, objective functions, constraints, solution techniques. Examples. Optimal distribution operational planning. Single objective functions, multiobjective formulations, constraints and solution methods. PART II – Distribution network switching and protection (27 hours): Definitions of overcurrent, overload and shortcircuit. Shortcircuit currents, symmetrical and unidirectional components. Generalities on the electric arc. Structure and operation of circuitbreakers for Medium and Low Voltage. Transient Recovery Voltage (TRV). Current interruption in threephase circuits. Functional schemes and applications. Generation and measurement of direct, alternative and impulsive high voltages. Interruption of direct currents and DC circuit breakers. Analysis of the neutral point connections (grounded, grounded through impedance, isolated). PART III – Service continuity and power quality (18 hours): distribution network automation, service restoration. Distribution system reliability, local and global reliability indicators. Waveform quality, harmonic distortion in unbalanced systems, voltage dips and related indicators. Flicker. Harmonic power flow. Commercial quality. PART IV – Distributed generation and resources (15 hours): Classification of the distributed resources. Distributed multigeneration. The role of the environment. Distribution network models with distributed resources. Local voltage control. Grid connection of the distributed resources. Island operation. Microgrids and evolution of the networks according to the smart grids paradigm. 
Delivery modes
In addition to lectures, the course programme includes the use of software tools laboratory activities.
Solution of problems with software tools (15 hours): distribution system power flow calculations; optimal reconfiguration; distribution system reliability; optimal distribution system planning. Laboratory and experimental activities (3 hours): measurements on electrical components and systems in nonsinusoidal operating conditions. Laboratory for thermal, highvoltage and highcurrent tests at INRIM Torino (6 hours). Possible technical visits at companies and industries. 
Texts, readings, handouts and other learning resources
Lecture notes and material available on the course web site.
There is no commercial text covering the whole course topics. Reference books: J. Arrillaga, N.R. Watson, Power system harmonics, 2nd edition, Wiley (ISBN 0470851295), 2003 R. Billinton, R.N. Allan, Reliability evaluation of power systems, 2nd edition, Plenum Press, New York (ISBN 0306452596), 1996. M. Bollen, Understanding power quality problems: voltage sags and interruptions, IEEE Press (ISBN 9780780347137), 2000. R.E. Brown, Electric power distribution reliability, Marcel Dekker (ISBN 0824707982), 2002 N. Jenkins, R. Allan, P. Crossley, D. Kirschen, G. Strbac, Embedded generation, IET (ISBN 9780852967744), 2000. W. H. Kersting, Distribution systems modeling and analysis, CRC Press (ISBN 0849308127), 2001. D.N. Gaonkar (ed.), Distributed Generation, Intech (ISBN 9789533070469), 2010. Available online at http://sciyo.com/books/show/title/distributedgeneration. Other references: T.E. Browne, Jr. (ed.), Circuit interruption  Theory and techniques, Dekker, New York, (ISBN 082477177X), 1984 C.H. Flurscheim (ed.), Power circuit breaker theory and design, Peregrinus, London, UK (ISBN 0906048702), 1975 R.D. Garzon, High Voltage Circuit Breakers, Dekker, New York (ISBN 082479821X), 1997 M. Khalifa (ed.), HighVoltage Engineering  Theory and practice, Dekker, New York (ISBN 0824781287), 1990 
Assessment and grading criteria
The file containing the detail of the topics addressed, referring to the four parts of the course programme, is posted on the web site at the end of the activities of the course and serves as a reference for preparing the exam.
The exam is oral. Access to the exam is subject to prior demonstration of the ability to solve application problems with the use of the personal computer; the acquisition of this kind of ability is tested during the activity in the computer laboratory, on the basis of the obtainment of the correct results by running the calculation programs. No written report has to be prepared. The students who do not demonstrate the acquisition of these skills during the course activities have the possibility to participate in a successive test based on the execution of the calculation programs, in one of the exam dates. The exam dates are agreed with the Commission during the scheduled exam periods. The oral colloquium generally includes four questions, one on each part of the course, and could include the discussion on material produced during the execution of the calculation programs and in the laboratory experiences. The final score refers to the knowledge and ability level reached on the different topics of the course programme. 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 nonpassed exam evaluation. 
