Single-ended line fault location method for multi-terminal HVDC system based on optimized variational mode decomposition

In order to provide a backup plan for double-ended fault location scheme when data communication and synchronization are not effective or available, a single-ended fault location method is proposed using traveling wave (TW) theory. The time-frequency characteristics is utilized to extract fault feature for fault location estimation. Specifically, Variational Mode Decomposition (VMD) is adopted and further improved with singular entropy based parameter optimization and TW arrivals can be clearly identified via intrinsic mode function (IMF) result. In order to solve the issue of highly attenuated TW front, Teager Energy Operator (TEO) is used to visualize the singular points in IMF and the peaks in TEO spectrum indicate the fault TW arrivals. Moreover, frequency dependent TW propagation velocity is determined by center frequency of selected IMF to enhance accuracy. The fault simulation is performed on the platform PSCAD/EMTDC based on example model of 15-bus CIGRE HVDC system and MATLAB is used for signal processing and algorithm development. The effectiveness and superiority of this method is verified with simulation study considering potential influence.