A hybrid fault locator for three-terminal lines based on wavelet transforms

This paper presents a hybrid fault location algorithm for three-terminal transmission lines based on wavelet transforms (WT). In this work, the WT were used to analyze the low and high frequency components of the current and/or voltage signals generated by an electric fault. A simple routine was used to determine which method should be used for each case. The methodology is called “hybrid” as it uses either traveling waves or impedance calculation methods to locate the fault. The traveling wave method analyses the current and/or voltage high frequency signals extracted by WT to determine the fault location. On the other hand, the fundamental frequency components of the voltage and current signals, also extracted by WT, can be used for the same purpose. The hybrid algorithm was tested for different fault conditions by simulations using alternative transients program (ATP) software. The results obtained are promising and demonstrate a highly satisfactory degree of accuracy and reliability of the proposed method.