Evaluation criteria for condition and importance assessment of high voltage transmission line

This paper proposes a program development for condition and importance assessment of high voltage transmission line in Thailand. The condition criteria consist of age, stress, symptom, failed-type, obsolescence, as well as environment and safety while importance criteria consider line loading, N-1 criteria, system stability, possible of force outage, pollution and social impact. The score and weight techniques are applied to the assessment. In addition, Analytical Hierarchy Process is used to determine weighting of criteria. The components of transmission system such as conductor, conductor accessories, insulator structure, foundation, lightning, accessories and right of way are evaluated while subcomponents of each component and classified. The 10 of 500 kV transmission lines in Thailand transmission network is used in example in the assessment program. The results show the criteria renovation index, equipment performance index, and equipment importance index in forms of percentage and finally risk of ten lines is shown in risk matrix. The results can provide an effective maintenance schedule for transmission system.