Learning objectives
1) Knowledge and understanding
Attending classes and through individual study, students are to acquire basic knowledge of:
- basic concepts and problems of the generation, transmission and distribution of electricity in power systems
- power, frequency and voltage control techniques
2) Applying knowledge and understanding
- A goal of this course is providing students with the ability of applying their knowledge of power electronics, energetics and controls to power systems
- importance is also given to the ability of solving quantitative problems and exercises.
Prerequisites
Students should be familiar with the notions of mathematics, physics, electrical engineering and power electronics typically acquired in first-level degrees in Information engineering (class L-8).
Course unit content
- Part 1: power circuits
1) Controlled rectifiers
2) AC/AC converters
3) Resonant DC/DC converters
4) Switching power supplies
5) UPS
- Part 2: power systems
6) Introduction and general concepts
7) Power and frequency control
8) Control of voltage and reactive power
9) Load flows
10) System stability
Full programme
- Part 1: power circuits
1) Controlled rectifiers - 6 hrs
Single-phase controlled rectifiers: half-wave rectifier; semi-converter; full converter; dual converter. Three-phase semi-converter and full converter. Multi-level rectifiers.
2) AC/AC converters - 4 hrs
On-off power control. Half-wave and full-wave controllers. Common-cathode switch. Single-SCR full-wave converter. Transformer tap changer. Single-phase and three-phase cycloconverter.
3) Resonant DC/DC converters - 2 hrs
L-type ZCS converter. ZVS converter. Half-wave ZCS converter.
4) Switching power supplies - 4 hrs
Linear vs. switching power supplies. Flyback converter. Forward converter. Switching power supply design.
5) UPS - 2 hrs
- Part 2: power systems
6) Introduction and general concepts - 6 hrs
General aspects. Generation of electric power: non-renewable and renewable sources. Electric power generation from renewable sources. Electrical energy storage. Transmission and distribution of electricity. Utilization and loads.
7) Power and frequency control - 4 hrs
Automatic Volate Regulator (AVR). Frequency control with variable load: the “governor”. Load sharing between generators. Power-frequency characteristics of an interconnected system. Systems connected by lines of limited capacity: effect of governor characteristics; frequency-bias-tie-line control.
8) Control of voltage and reactive power - 8 hrs
Generation and absorption of reactive power: synchronous generators. Relationships among voltage, active and reactive power at a node. Voltage control techniques: reactive power injection; parallel and series capacitors; synchronous compensators; reactive power injection by SVCs and STATCOMs; tap-changing transformer; phase-shift transformer. Voltage collapse. Control of voltage in distribution networks. Long lines.
9) Load flows - 2 hrs
Introduction: circuit analysis and load flow analysis. Relationship between load flows and voltage at nodes. The Gauss-Seidel method.
10) System stability - 4 hrs
Steady-state and transient stability.
Bibliography
- Part 1: power circuits
M. H. Rashid, Power Electronics: Circuits, Devices, and Applications, 2nd Edition, Prentice-Hall, 1993.
- Part 2: power systems
B. M. Weedy; B. J. Cory; N.Jenkins; J. B. Ekanayake, G Strbac, "Electric Power Systems," 5th Edition, Wiley, 2012, ISBN-13: 9780470682685.
Teaching methods
Classroom lectures, featuring exercises and numerical examples solved by the instructor.
Assessment methods and criteria
Oral exam.
Students will have to show good understanding of the theoretical aspects treated in the lectures, and the ability to solve simple quantitative exercises by hand calculations.
The student is typically required to answer to two questions, one on the topics of part 1 (1-5), one on those of part 2 (6-10).
Students can choose to speak either Italian or English at the exam. Students who show sufficient fluency with technical english are awarded up to 2 extra points (out of 30).
Other information
The course web site can be found on the Elly platform.
