A LMF based broken strand faults detection scheme for steel core in ACSR

Overhead transmission lines generally operate in the wild harsh environment, and can be damaged for all kinds of causes. Steel stranded wire plays a supportive role for aluminum conductor steel-reinforced (ACSR), so that detection for broken strand of steel core is an important mean to insure safety operation of transmission lines. As steel core is wrapped in the ACSR, it is hard to detect broken strand fault by traditional artificial distance method. Overhead transmission line inspection robot examines the conductor with detectors, so a detection scheme and correspondingly sensor based on leakage magnetic flux (LMF) theory for broken strand of steel core in ACSR is developed by this paper. The density of LMF field is calculated in the different degree damage and location of steel core in ACSR. The influence of magnetic field generated by transmission current to the detection scheme proposed by this paper is analyzed. Theoretical analysis and simulation results show that the proposed scheme based on LMF can detect all kinds of broken strand faults of steel core in ACSR with high precision and reliability. The principle of the proposed detection scheme is simple, so it could be applied to engineering practice.