Enhancing HVDC Transmission System Reliability Using a Novel Technique for Fault Type Classification and Fault Location Determination

Reliable fault detection and accurate fault location are critical challenges in high-voltage direct current (HVDC) transmission systems, particularly under high-resistance fault conditions where conventional protection schemes may exhibit reduced sensitivity. This paper presents a novel protection approach for bipolar HVDC transmission lines based on double-terminal current traveling wave analysis combined with discrete wavelet transform (DWT). The proposed method utilizes current measurements from both the sending and receiving terminals and applies the Daubechies-4 (db4) wavelet to extract high-frequency transient components for fault-type discrimination. Fault location is determined using the arrival times of the first traveling waves at both line terminals. The proposed algorithm is validated using a MATLAB/Simulink model under various fault scenarios, including pole-to-ground and pole-to-pole faults, different fault locations, and high fault resistance values. Simulation results demonstrate that the method accurately identifies fault type and estimates fault location with a maximum error of 0.11%, even for fault resistance up to 100 Ω. Additional analysis confirms robustness under varying operating conditions, transmission line lengths, and noisy measurement signals. Comparative evaluation with recently published methods show that the proposed technique offers improved accuracy, reliability, and suitability for real-time implementation in HVDC protection systems.