Electric-Field-Based Reconstruction of Transmission-Line Galloping Characteristics Using an Arc-Length Constraint

Conductor galloping threatens the safe operation of overhead transmission lines, motivating non-contact methods for reconstructing its motion characteristics. However, recovering conductor displacement from electric-field measurements near the suspension point requires resolving the coupled effects of deflection and sag. This study develops an electric-field-based reconstruction method that combines local angle inversion with an arc-length constraint. A three-dimensional conductor model relates the tangential deflection angles to multipoint electric-field observations, and relative amplitude measurements provide the inputs for local Jacobian inversion. The reconstructed angles are combined with prescribed spatial modes and the inextensibility constraint to obtain horizontal and vertical displacement components while accounting for sag variation. Spectral analysis of the reconstructed motion sequences extracts the dominant frequencies. The observation model is further extended to three-phase electric-field superposition with known relative phase-voltage magnitudes and phases. Controlled single-conductor laboratory tests evaluate displacement reconstruction against scale references, while separate known-input numerical comparisons assess angle, displacement, and frequency recovery. Error analyses examine the effects of measurement perturbations, geometric uncertainty, and observation sensitivity on reconstruction. The results support recovery of the overall imposed motion patterns while identifying direction-dependent deviations and sensitivity to low-amplitude inputs. The method provides a basis for reconstructing conductor galloping characteristics from local electric-field measurements under specified geometric and measurement conditions.