Condition Assessment of Overhead Transmission Line Using Weighting and Scoring Method and IT Application

This paper aims to develop a novel approach for the condition assessment and maintenance management of 115, 230, and 500 kV overhead transmission lines, as well as a data management system. The criteria for assessing the condition are defined using the annual climbing visual inspection, technical laboratory tests, and special tests, e.g., conductor tensile strength, torsional ductility, and thermography tests. The weighting and scoring technique is effectively applied for the condition assessment of eight major components of a transmission line. According to recommendations from several manufacturers, international standards, and experiences of the maintenance crew, the classification score of the condition of major components ranges from very good to end of life. The weighting, used to calculate the component and transmission line health indices, is determined by applying the analytic hierarchy process to brainstorm opinions from experts in a transmission utility working with transmission lines. The obtained assessment can be further used to assign proper maintenance tasks: a normal-condition line requires routine inspection and scheduled maintenance, a medium-condition line requires more frequent inspection and scheduled maintenance, and a poor-condition line requires urgent repair/replacement of the defective component. The proposed procedure is subsequently developed as a web-based application to create a centralized database of transmission lines in terms of technical data and inspection results, to facilitate data collection during routine inspection, and to quickly and systematically process the stored data to determine the condition of a transmission line. This program has been satisfactorily used in the transmission utility to effectively manage the maintenance tasks of transmission lines.