masterThesis
Estimação de Fasores para Proteção de Sistemas Elétricos Baseada em Mínimos Quadrados e Morfologia Matemática
Fecha
2012-12-18Registro en:
FORMIGA, Diego Alves. Estimação de Fasores para Proteção de Sistemas Elétricos Baseada em Mínimos Quadrados e Morfologia Matemática. 2012. 114 f. Dissertação (Mestrado em Automação e Sistemas; Engenharia de Computação; Telecomunicações) - Universidade Federal do Rio Grande do Norte, Natal, 2012.
Autor
Formiga, Diego Alves
Resumen
This work proposes a new technique for phasor estimation applied in microprocessor
numerical relays for distance protection of transmission lines, based on the recursive least
squares method and called least squares modified random walking. The phasor estimation
methods have compromised their performance, mainly due to the DC exponential
decaying component present in fault currents. In order to reduce the influence of the
DC component, a Morphological Filter (FM) was added to the method of least squares
and previously applied to the process of phasor estimation. The presented method is implemented
in MATLABr and its performance is compared to one-cycle Fourier technique
and conventional phasor estimation, which was also based on least squares algorithm. The
methods based on least squares technique used for comparison with the proposed method
were: forgetting factor recursive, covariance resetting and random walking. The techniques
performance analysis were carried out by means of signals synthetic and signals
provided of simulations on the Alternative Transient Program (ATP). When compared to
other phasor estimation methods, the proposed method showed satisfactory results, when
it comes to the estimation speed, the steady state oscillation and the overshoot. Then,
the presented method performance was analyzed by means of variations in the fault parameters
(resistance, distance, angle of incidence and type of fault). Through this study,
the results did not showed significant variations in method performance. Besides, the apparent
impedance trajectory and estimated distance of the fault were analysed, and the
presented method showed better results in comparison to one-cycle Fourier algorithm