Estudo e implementação de técnicas de análise de componentes supraharmônicos

Abstract

In the last decades, electric power distribution and transmission systems have been equipped with technological resources with a high degree of automation, in order to significantly increase their efficiency and control of the energy flow. The grid that provides such advantages and innovations to the conventional power system is cal led Smart Grids. Smart grids encourage the use of new technologies such as electric vehicles, intelligent metering systems as well as the use of renewable energy sources. One of the crucial challenges in the creation of Smart Grids is the improvement of the power quality available in the grid. In addition to the emission of harmonics and other distortions located in the frequency range below 2 kHz, these new technologies are also responsible for emissions in the range of 2 kHz to 150 kHz, usually referred to supharmonics. The supraharmonic distortions analysis has not been explored for years due to the lack of standards and measuring equipment capable of reaching this frequency range. In the last years, with the increased use of supraharmonic emitting devices, the frequency range above 2 kHz has become the object of study of power quality (PQ) researchers. This work is aimed to contribute to the improvement of the analysis of these frequency components and, in this sense, it proposes a techni que to access the supraharmonic components of the signal with reduced sampling rate and refined frequency resolution. The proposed structure contemplates the use of an analog filter bank, the application of the concept of subsampling and the use of the Compressive Sensing (CS) technique. The filter bank acts on the decomposition of the analyzed signal, separating it into its supraharmonic components. Subsampling was used as a strategy to decrease the sampling rate. The CS algorithm represents a powerful tool that enables an improvement in the frequency resolution of the suprahar monic estimation. Subsequently, a new methodo is developed based on digital filter bank to supraharmonic estimation. The employed approach exploits different concepts of digital signal processing, such as uniform DFT filter bank, multirate filtering and polyphase representation. The methodologies proposed showed quite expressive results in relation to both in the supraharmonic estimation efficiency and to the computational performance