Sumários
Review of symmetric faults; introduction to unsymmetric faults
6 novembro 2018, 09:30 • Luis Marcelino Ferreira
Review of all formulas for 3-phase symmetric short-circuits analysis: Voltages and currents everywhere for a short-circuit anywhere
How to use the Z matrix and review of its definition
Starting to look at 3-phase non-balanced systems
Are the systems symmetric wrt phases?
The idea behind symmetric components
Direct, inverse and homopolar
Positive, negative, zero sequences
Fortescue transformation T of F
Illustration of unsymmetrical voltages from direct, inverse and homopolar components
Strong case of assymetry: single phase fault (to ground)
Use of Vabc and Iabc and Zabc directly
Envision the alternative: Vdih, Idih, Zdih
Zdih is diagonal and is obtained from Zabc -- could you do it yoursel?
Notes on hermitian and ortogonality: T, T’, and T^-1
Continuation of study of symmetric faults
30 outubro 2018, 09:30 • Luis Marcelino Ferreira
Review of last class
Review of basic concepts: driving point impedance and trans-impedance (transfer impedance)
How to find voltages and currents anywhere in a fault situation
Steps and base formulas