Protection scheme for multiterminal HVDC system based on wavelet transform modulus maxima

Fault protection is a major issue in the development of multiterminal high-voltage direct current (HVDC) system based on voltage-source converter. Owing to the rapid increase in fault current under DC faults, protection requires a fast fault detection method to isolate the fault current. However, the selectivity and reliability of the fast protection scheme should be primarily guaranteed. Therefore, a new protection strategy based on modulus maximum under wavelet transform is proposed in this paper. Fault detection and discrimination are achieved using single-end signals of fault current. The external and internal faults can be discriminated via local information. The reliability and robustness of the proposed scheme against potential factors are verified. Numerous simulation cases are performed in PSCAD/EMTDC under different fault scenarios, and signal data are analyzed in MATLAB to demonstrate the effectiveness of the proposed fault protection scheme. (c) 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.