Classificação de faltas e seleção de fases para linhas de transmissão com meio comprimento de onda

Abstract

Growing demand for electricity around the world contributes increasingly to the expansion of power transmission systems. Therefore, to harness the produced energy it is necessary to establish connections between these regions with high energy potential and the load centers. Very long-distance point-to-point connections are currently made over High Voltage Direct Current lines. In the 1930s the first studies were made in the former Union of Soviet Socialist Republics, showing that the AC line has a robust behavior in terms of voltage, current and stability of the system when its electrical length corresponds to half of the electromagnetic wavelength (2500 km to 60 Hz). However, the usual simplifications with respect to modeling are no longer valid due to its long length, implying several inadequacies of the paradigms and traditional methodologies of protection of electrical power systems. In this work, using the MATLAB software, it was obtained a model coherent with the behavior of a half wave transmission line, based on a real proposal evaluated in the Brazilian Grid, with the objective of analysing the performance of fault classification and selection techniques proposed for this line and also the assembling of a method, based on the uncoupled currents variation, through modal transforms. The methods were evaluated for different load conditions and fault resistances in order to obtain answers about their robustness.