A hybrid UHVDC transmission system applying LCC as the rectifier and MMC as the inverter combines the advantages of both converter types, which makes this protection scheme more complicated. A new pilot protection scheme for a three-terminal hybrid DC transmission system applying energy functions is proposed. The energy function for LCC is applied to MMC to derive the energy level of the hybrid system. Furthermore, an improved Hausdorff distance (IHD) algorithm is proposed to detect the difference in energy levels between the normal and fault states. An abrupt change in energy level is characterized by IHD change rate. Time points at which the IHD change rate exceeds the threshold at converter stations are applied to determine the fault line and to estimate the fault section. The proposed protection scheme is then verified by a simulation model of the Wudongde
Publications
Article type
Year
Open Access
Regular Paper
Issue
CSEE Journal of Power and Energy Systems 2024, 10(3): 891-902
Published: 03 March 2023
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