Análise de Sistemas Elétricos

Per unit system (p.u.). Power Flow Analysis: bus admittance matrix, active and reactive power flow balance equations, Newton-Raphson method, Fast Decoupled Power Flow (FDPF) method, DC power flow method.

The teaching methodologies, that promote active and collaborative learning, follow a temporal sequence that enables students to acquire theoretical concepts, solve a set of exercises and carry out practical case studies.

Goals
The main aims of this course unit are:
– to model major types of components used in electrical power systems;
– to analysis fault conditions including both balanced and unbalanced faults;
– to understand the use of sequence networks in the analysis of faults and unbalanced power system operation;
– to evaluate the electric power system dynamics and its stability;
– to acquire knowledge to analyse the security of an electrical power system and propose/implement measures to improve it;
– to understand the basics of power system protection systems.

Skills
At the end of this course unit the learner is expected to be able:
– to know the characteristics and behaviour of an electric power system;
– to understand and apply the techniques required to analyse the effects of short-circuits in an electric power system;
– to manage, design, implement and maintain electrical power systems;
– to design and conduct experiments and to analyse and interpret data;
– to identify, formulate and solve engineering problems;
– to communicate in a professional and technical manner, both in written and oral form, the subjects related to this course.

Program Contents

1. Short-circuit Analysis
– Introduction
– Symmetrical Fault Analysis
– Electrical Power System Models: Generators, Transformers, Lines and Loads
– Short-circuit Capacity
– Algorithm for Short Circuit Studies
– Bus Impedance Matrix Formulation
– Systematic Fault Analysis using Bus Impedance Matrix
– Symmetrical Components
– Sequence Impedances of Generators, Transformers, Transmission Lines and Loads
– Construction of Sequence Networks of a Power System
– Methods for measurement of symmetrical components
– Unsymmetrical Fault Analysis
– Symmetrical Component Analysis of Unsymmetrical Faults: Single Line-To-Ground (LG) Fault, Line-To-Line (LL) Fault, Double Line-To-Ground (LLG) Fault
– Bus Impedance Matrix Method for Analysis of Unsymmetrical Shunt Faults
– Limitation of short circuit currents

2. Power Systems Security Analysis
– Introduction
– An Overview of Security Analysis, Factors Affecting Power System Security, Detection of Network Problems
– Contingency Analysis: Linear Sensitivity Factors, Calculation of Network Sensitivity Factors, AC Power Flow Methods, Contingency Selection

3. Power System Stability
– Introduction
– Dynamics of a Synchronous Machine
– Steady-State Stability
– Transient Stability: Equal Area Criterion, Numerical Solution of Swing Equation, Multimachine Stability, Some Factors Affecting Transient Stability
– Voltage Stability

4. Power System Protection
– Protection concepts
– Protective devices and controls, Transmission protection, Apparatus protection
– System aspects of protective systems

5. Introduction to SCADA and Control Centres, EMS/DMS, importance and functions

NAO

Mandatory literature (available in the ISEC library):
– Paiva, J. P. (2007). Redes de Energia Eléctrica, uma Análise Sistémica (2ª ed.). IST Press.
Cotas: 1-2-262 e 1-2-264 (two available)
– Saadat, H. (1999). Power System Analysis. McGraw-Hill.
Cotas: 1-2-153 e 1-2-394 (two available)

Complementary Bibliography
– Gómez-Expósito, A., Conejo, A. J., & Cañizares, C. (Eds.). (2018). Electric Energy Systems: Analysis and Operation (2nd Ed.). CRC press.
– Glover, J. D., Sarma, M. S., Overbye, T. & Birchfield, A. (2022). Power System Analysis and Design (7th Ed.). Cengage Learning.
– Delgado, M. (2011). Protecção das Redes Eléctricas de Distribuição, Transporte e Interligação. Publindústria, Edições Técnicas.
– Castro, R. & Pedro, E. (2014). Exercícios de Redes e Sistemas de Energia Elétrica. IST Press.

Available Support Material
Lecture notes, notes of practical classes and examples of practical exercises.