AC spectrum analysis for detecting DC faults on HVDC systems

This paper analyzes the impacts of Direct Current (DC) faults on the AC side for Voltage Source Converter (VSC)-based High Voltage Direct Current (HVDC) systems. This aims to understand deeply the system behavior under such faults. DC faults with pole-to-ground type on DC transmission lines is mainly considered as it is the most popular faults in HVDC systems. Performance during pole to pole faults is also examined. As observed, the current and voltage waveforms in the AC grid system are distorted due to the DC faults occurrence. Then, analyzing the spectrum of the AC waves is performed under different fault cases. A basic detailed MATLAB simulation model is utilized to study the system performance of the prepared test cases. The results confirmed the possibility of implementing an efficient spectrum analysis tool to detect DC faults for HVDC systems to be utilized as a backup DC fault detection method.