Current Reconstruction and Sag/Wind Deflection Monitoring of Transmission Lines by Magnetic Sensing

The nonintrusive condition monitoring of overhead transmission lines is a key method to ensuring the safe and stable operation of transmission systems. Especially, their sag/wind deflection are important parameter that should be monitored along with its current. In this article, an innovative approach for noncontact and cost-effective monitoring of high-voltage overhead transmission lines (HVOTLs) is developed, utilizing three uniaxial magnetic sensors strategically positioned on the tower, below (or above) the transmission lines. Initially, a magnetic field (MF) decoupling method in the context of spatial state variations across multiple conductors is proposed. Subsequently, an algorithm is presented to perform sag estimation, wind deflection detection, as well as current reconstruction. The efficacy of the proposed approach is corroborated through numerical simulations and finite-element analysis (FEA). Further validation is achieved using a scaled-down model in the laboratory, reinforcing the practical feasibility of the method.