Fault Detection with Strong Anti-interference Capability and Wider Scope for VSC-MTDC System

Voltage source converter-based multi-terminal DC transmission (VSC-MTDC) system has long-term development prospects, but its protection scheme has poor anti-interference ability. A double-ended protection principle with strong anti-interference ability is given. First, virtual measured wave impedance expression is obtained through equivalent circuit of VSC-MTDC system, and its amplitude characteristics are analyzed accordingly. Then, changes in virtual measurement wave impedance (VMWI) are obtained by analyzing reflection coefficient. Finally, Euclidean distance with weighted is introduced to characterize fault. Theoretical analysis and simulation verify anti-interference ability of the proposed scheme. Results show the proposed scheme has strong anti-interference ability. Results indicate the scheme enhances anti-interference ability and applicable scope of existing scheme.