Teoria das wavelets: estudo e aplicação na análise de transitórios em sistemas de potência.

Abstract

Transient phenomena in power systems are caused by switching operations, faults, lightning surges and other disturbances. These phenomena can produce overvoltages, overcurrents, harmonic distortion and electromechanical transients. So, the simulation of transient phenomena is an important subject for system protection coordination and power quality studies. With the advent of digital computer, many methods have been developed for transient analysis, which are generally classified in two main groups: transform-domain and time-domain methods. The methods of both classes have advantaçes and disadvantages depending on the application. However, they have some common drawbacks: they are not adequate for analysis of short duration transient superimposed with low frequency. Recently, methods based on the wavelet theory have been proposed for transient analysis. Two of these methods are studied: Chen & Hsiao method and Meliopoulos & Lee method. Chen & Hsiao method is modified for support non-null initial conditions and non-linear elements. This study resulted on a altemative method for transient analysis. Detailed study of the wavelet theory and applications to typical problems of power systems are carried out.