Wavelet-Based Detection of Transients Induced by DC Faults Using Boundary Protection Principle

This paper presents a high-speed method for direct current (DC) line fault detection based on the boundary protection principle. It uses only the DC current signal by means of the first level wavelet coefficients resulted from stationary wavelet transform (SWT). There is no need for communication links, and an objective and generic strategy to determine the occurrence of these internal faults is proposed. Simulation results are presented in order to evaluate the suggested method performance addressing the critical cases of DC faults, alternating current (AC) faults at rectifier and inverter sides, and commutation failures.