OPTIMAL DESIGN OF MFL SENSOR FOR DETECTING BROKEN STEEL STRANDS IN OVERHEAD POWER LINE

Aluminum conductor steel-reinforced (ACSR) cable is a specific type of stranded cable typically used for electrical power delivery. Steel strands in ACSR cable play a supportive role for overhead power line. Inspection timely is an important means to insure safety operation of power lines. As steel strands are wrapped in the center of ACSR cable, the common artificial inspection methods with optical instruments are limited to find inner flaws of power line. Recently, inspection of power line by robot with detectors is a method with good prospect. In this paper, the optimal design model of detector based on magnetic leakage flux (MLF) carried by robot for detecting broken steel strands in ACSR cables has been proposed. The optimal design model of MFL sensor is solved by niche genetic algorithm (NGA). Field experiment results show that the design method of the detector can be applied to different types of ACSR cables. The magnitude field induced by transmission current has nearly no influences on the detection of broken steel strands, and the developed detector carried by robot can identify broken steel strands with high reliability and sensitivity.