Análise comparativa entre métodos de detecção de faltas em linhas de transmissão do tipo HVDC.

Abstract

With the development of new devices in power electronics, direct current transmission is becoming more and more common, and its use is more advantageous in certain situations than the transmission in alternating current. Based on this importance, it is proposed to carry out a comparative study between the methods of detecting faults in direct current transmission lines. The selected methods for comparative study belong to the group of methods based on the theory of traveling wave. The methods used were those based on the discrete wavelet transform, the redundant discrete wavelet transform, the Park transform and a method based on the energy of the signal derivative. The performances of the methods are compared based on simulations performed via MATLAB/Simulink of two different configurations of HVDC systems, a monopolar and a bipolar system. In the analyses to evaluate the performance of the methods, the fault points, fault type and fault resistance were varied in order to test the robustness of the methods for high and low impedance faults. In all the evaluated methods, a self- adaptive threshold for fault detection was applied. From the results it was verified that the methods that obtained the bests results were those based on the energy of the signal derivative and the method based on the Park transform. The method based on signal derivative energy has simpler code, when compared to the method that makes use of the Park transform, thus performing the detection of faults faster.