Sumários
Reviews
15 dezembro 2016, 11:00 • Luis Marcelino Ferreira
Questions
Should DY transformers be considered as phase-shifters?
Role of DY and role of phase-shifters
Os transformadores DY devem ser considerados como phase-shifters?
The clock hour for phase-shift representation in DY, YY, and DD transformers
Resolution of part of a past exam, 18Jan13
Circuit compensation for contingency analysisHVDC links
13 dezembro 2016, 09:30 • Luis Marcelino Ferreira
Why DC links
Advantages and disadvantages
Losses, transmission capacity, induction and capacitance of transmission lines and cables
Conversion stations (rectification and inversion)
Figures for the rectification inversion process
Valves and thyristors
Firing angles: alpha and gamma
Structure of the stations: multiple transformers, large inductors and capacitors, filters
High voltage and high power
Circuit model of a HVDC link: controlled-voltage sources and resistances
Resistance at commutation
Voltage sources controlled by alpha, gamma, and transformer tapsProblem9 and Problem10
13 dezembro 2016, 08:00 • Luis Marcelino Ferreira
Discussion of Problem9
Step by step solution, following code
Numerical results
Drawings of phasor diagrams
Complete voltage phasor diagrams, with 12 voltage phasors
Discussion
Presentation and discussion for Problem10
Reviews and Problem11
6 dezembro 2016, 09:30 • Luis Marcelino Ferreira
Reviewing of critical aspects of unsymmetrical faults
Problem11
Review of state estimation problem
Identify the state
Identify the function
Run optimization
Compute the objective
Interpret the results