Detecting broken strands in transmission line - Part 1: Design of a smart eddy current transducer carried by inspection robot

Abstract

SUMMARY Transmission line is the primary facility for power delivery and is mainly composed of twisted aluminum wires. During the long-term outer door field service, overhead transmission lines will encounter strikes of lightning, corrosion of chemical contaminants, ice shedding, wind vibration of conductors, lines galloping, damage due to external forces and so on which will generally bring a series of latent faults such as aluminum strands fracture. It will induce some fatal accidents such as broken transmission lines which have a very strong impact on the safe operation of power grids if the latent faults can not be recognized and restored as early as possible. The method of detecting broken strands in transmission line by inspection robot with detectors is a method with good prospect. In this paper, a kind of eddy current transducer (ECT) for detecting broken strands in transmission line is developed. The developed ECT can be integrated to the transmission line inspection robot. Simulation and field experiment results show that the magnitude field induced by transmission current has no influence on the detection of broken strands in transmission line. Hence, the developed ECT carried by robot can identify broken strands with high reliability and sensitivity. At the same time, the proposed structural style and design method of the ECT can be applied to different types of transmission line. Copyright © 2012 John Wiley & Sons, Ltd.