Magnetic-Field-Sensing-Based Approach for Current Reconstruction, Sag Detection, and Inclination Detection for Overhead Transmission System

Noncontact monitoring technique of mechanical and electrical states is increasingly attractive for the overhead transmission system. This paper proposes a new technique to detect the tower inclination and transmission line sag, and measure transmission current simultaneously. The key of this technique is to use the ground magnetoresistive (MR) sensor to measure the magnetic flux density along the center line from the three-phase transmission lines. Moreover, the magnetic field (MF) calculation formulas for a tilted tower are given in this paper. Finally, with MF calculation formulas, an algorithm based on artificial immune system (AIS) is applied to estimate the transmission line sag and tower tilt angles, and reconstruct currents. Model simulations of an overhead transmission system are carried out to verify the idea. The simulation results validate the feasibility of this noncontact approach to estimate mechanical parameters and reconstruct electrical parameters for overhead transmission system.