Non-Unit Protection for HVDC Grids: An Analytical Approach for Wavelet Transform-Based Schemes

Speed and selectivity of DC fault protection are critical for High-Voltage (HVDC) grids present significant technical economic challenges. Therefore, this paper proposes a non-unit solution that detects discriminates faults based on frequency domain analysis the transient period faults. The representation generic HVDC grid section corresponding DC-side signatures in form basis generalized approach analytically designing scheme Wavelet Transform (WT). proposed is adaptive within its design stage offers general applicability immunity to system changes, while settings configured optimized performance. validated through offline simulations PSCAD/EMTDC feasibility algorithm real world demonstrated use real-time digital simulation (using RTDS) Hardware-in-the-Loop (HIL) testing. Both demonstrate able detect discriminate between internal external at significantly high speed, remaining sensitive impedance robust disturbances outside noise.