Wavelet-Based Analysis and Detection of Fault-Induced Transients in HVDC Systems
Fault-induced transients, traveling waves, wavelet transform, fault detection and location, HVDC systems.
A fast and accurate detection of the transients is essential to ensure a reliable protection system capable to act with high-speed. In this work, a theoretical foundation regarding the highvoltage direct current (HVDC) transmission systems and the wavelet transform is provided. Then, a qualitative analysis of the traveling waves induced by faults on direct current (DC) transmission lines of HVDC systems is presented for detecting the wavefronts arrival times using the boundary wavelet coefficients from real-time stationary wavelet transform (RT-SWT). This qualitative analysis takes into account the steady-state and the detection of the inception times of both first and second wavefronts at the converter stations. The behavior of the boundary wavelet coefficients in DC transmission lines is examined considering the effects of the main parameters that influence the detection of the traveling waves, such as mother wavelets, sampling frequency, DC transmission line terminations, as well as fault resistance and distance. An algorithm designed to run in real-time and with self-adaptive criteria is proposed to detect the surge arrival times. Quantitative results were achieved based on the accuracy of one- and two-terminal fault location estimation methods to evaluate the algorithm performance.