A Single-Ended Fault Location Method for DC Transmission Lines Based on Inverse Distance Weighted Interpolation

The accuracy and reliability of single-ended fault location methods are often affected by boundary elements and transition resistances. This paper proposes a single-ended fault location method for DC transmission lines based on the initial traveling wave dominant frequency (ITWDF) attenuation characteristics. Firstly, the attenuation characteristics of the initial traveling wave frequency component are analyzed, and the attenuation law and distribution differences between the frequency component and fault distance are revealed. Secondly, to accurately extract and describe the trend of the initial traveling wave frequency component with the change of fault distance, the energy of the initial traveling wave is constructed, and the mathematical expression of the ITWDF related to the fault distance and unit length distortion coefficient is obtained. Theoretical analysis verifies that the ITWDF exhibits a monotonic attenuation mapping relationship with increasing fault distance. In addition, the attenuation characteristics of the ITWDF are not affected by fault impedance. Finally, a fault sample set containing the ITWDF and reference unit length distortion coefficients at different positions is constructed. The fault location is calculated using the ITWDF and the reference unit length distortion coefficient, with continuous wavelet transform and inverse distance weighting interpolation algorithms applied, respectively. Simulation results show that the proposed method can reliably locate faults under high-impedance conditions of up to 800Ω, and the absolute error is less than 200m. Moreover, the proposed method can be applied to DC lines with various boundary structures, improving the reliability of single-ended fault location.