Qualità e Sicurezza Elettrica MOD A
The course aims to provide the basic concepts related to metrology and power quality problems as well as tools needed to analyze the problems of electrical safety.
1.Knowledge and understanding
The student must know:
-the general criteria of measurement and evaluation of power quality disturbances
-the laws on the electrical safety.
-the general criteria for designing the protections against overcurrent and against direct and indirect contacts.
2.Applying knowledge and understanding
The student must demonstrate to be able
-to integrate knowledge in the field of power quality disturbances and electrical power systems.
-to apply the criteria for the selection and use of protective installation against electrical risk.
The student must demonstrate that he has the basic knowledge for dealing and deepening in an autonomous way the issues related to the power quality and electrical safety problems.
The student must demonstrate the ability to easily explain to people
- the methodologies for the evaluation and reduction of the power quality disturbances
- the solutions adopted in the electrical distribution systems for the achievement of prefixed safety levels.
The student must be able to update information about power quality and electrical safety problems through texts, standards and publications in order to acquire the ability to undertake further courses, specialized seminars and master
The student must have acquired the following knowledge provided by the courses of "Electrical circuits and Network Analysis" and "Electrical power systems":
The circuit model: ideal circuit elements, voltage and current. Kirchhoff’s laws. Linear resistive circuits: series and parallel equivalence, superposition principle, Thevénin-Norton’s theorem. Linear circuits in DC and AC steady state. Complex power, active power, reactive power, and conservation properties. Dynamical circuits, general methods of solution. Symmetric three-phase circuits: balanced, unbalanced.
Normal and abnormal operating conditions of an electrical power system; overcurrent and over voltage protection systems
a) Power quality (PQ)
Definitions and basic concepts of measurements. (1 ECTS – 8 hours)
Classification of PQ disturbances. (0,5 ECTS – 4 hours)
Main PQ disturbances (0,5 ECTS – 4 hours)
Harmonic distortions: definitions, evaluation methods, indices and objectives (1,5 ECTS – 12 hours).
Main solutions to minimize disturbance levels. (0,5 ECTS – 4 hours)
Interruptions: definitions, evaluation methods, indices and objectives (1 ECTS – 8 hours).
Voltage sags: definitions, evaluation methods, indices and objectives (0,5 ECTS – 4 hours).
Main solutions to minimize interruptions and voltage sags. (0,5 ECTS – 4 hours)
b) Electrical safety
Introduction on Electrical safety (0.5 ECTS - 4 hours): definition of security and risk, security of a system, reliability and security, the acceptable level of security.
The legislative bases of security (0.5 ECTS - 4 hours): CEI Standards, the DM 37/08.
Overload protection devices (0.75 ECTS - 6 hours): current rating of the cable, overload capability curve of a cable, time-current characteristic curves of protection devices, requirements for the overload protection device(circuit breakers, fuses)
Short-circuit protection devices (0.75 ECTS - 6 hours): recalls on the short-circuit current, thermal stress on a cable in short circuit conditions, short circuit current calculation, requirements for the short-circuit protection device (Fuses and Circuit breakers)
Effect of current on the human body (1.25 ECTS - 10 hours): introduction to electrical shock Limits of the electric current, electrical resistance of the human body, the earth resistance and resistance to earth of a person, full voltage and touch voltage.
Protection against direct contact (0.25 ECTS - 2 hours):total and partial protection measures
Protection against indirect contact - TT system (1.0 ECTS - 8 hours): protection by means of maximum current devices, limits of maximum current protection, protection by means of a differential circuit breaker, selective coordination, earthing system
Protection against indirect contact - TN system (0.5 ECTS – 4 hours): equivalent circuit, distribution circuits and terminals, differential circuit breakers sizing of the Earthing Resistance of HV/MV Transformer
Testing and inspection (0.5 ECTS – 4 hours): DPR 462, measuring earth resistance, test of differential circuit breaker
Power quality and safety course includes are the following: description of the electronic measurement systems and of the fundamentals on measurement uncertainty. Power quality: fundamental definitions, methods for disturbance levels evaluation, indices, objectives and technical solutions for disturbance limitation. Electrical safety: legislation and regulations on electrical safety. Design of protection systems against overcurrents. Protection against direct contact and indirect contact. Electrical safety testing.
Lectures, classroom exercises
Caramia, P., Carpinelli, G. and Verde, P. Power Quality Indices in Liberalized Markets, John Wiley & Sons, Ltd, Chichester, UK, 2009.
V. Carrescia, Fondamenti di sicurezza elettrica, TNE, Torino.
Peter E. Sutherland: Principles of Electrical Safety, John Wiley & Sons
Notes provided by the teacher
The exam consists in an oral test in which the level of knowledge of the topics addressed during the course will be assessed. The oral exam typically involves two questions about power quality (one on definitions, causes and effects of power quality disturbances; the other one on power quality indices and compensation methods) and two questions about electrical safety (one on overcurrent protection systems and one on protection against contact). The exam has a total duration of about one hour. The final grade is the average of the grades obtained by the student for the four questions.
Information about the time table for student interaction are at the following link
Lectures are in Italian. The professor is fluent in English and is available to interact with students in English, also during the examination.