The fault characteristics of voltage source converter-based high voltage direct current(VSC-HVDC)transmission systems connected to offshore wind farms differ from those of conventional power systems.Conse-quently,there exists a potential risk of inadequate adaptability when conventional relay protection schemes are ap-plied to the VSC-HVDC transmission system.This paper analyzes the impact of harmonic components induced by asymmetrical electrical quantities,negative sequence suppression,and current-limiting measures on the perfor-mance of differential protection during fault ride-through(FRT).Sensitivity calculation formulas for differential pro-tection considering sequence components are derived,and adaptability analysis is conducted.It is noted that differ-ential protection is susceptible to odd-order harmonics during fault conditions,while negative sequence suppression and current-limiting measures may also diminish its sensitivity.Extensive simulation calculations are carried out us-ing a simulated system of a practical demonstration project.The findings indicate a decrease in the sensitivity and re-liability of conventional differential protection schemes.
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