Review and Evaluation of the State of the Art of DC Fault Detection for HVDC Grids

This paper reviews the state of the art of DC fault discrimination and detection methods of HVDC grids, and summarises the underlying principles and the characteristics of each method. To minimize HVDC grid disturbance and power transfer interruption due to DC faults, it is critically important to have protection schemes that can detect, discriminate and isolate DC faults at high speeds with full selectivity. On this basis, this paper lists the advantages and disadvantages of the most promising fault detection methods, with the aim of articulating the future directions of HVDC protection systems. From the qualitative comparison of relative merits, the initial recommendations on HVDC grid protection are presented. Moreover, a comprehensive quantitative assessments of different fault detection methods discussed above are carried out on a generic 4-terminal meshed HVDC grid, which is modelled in PSCAD environment. The presented simulation results identify that the voltage derivative and wavelet transform are the most promising methods for DC fault detection and discrimination.