Cumulative damage risk assessment for transmission tower-line system considering copula-based joint distribution of wind speed and direction

This paper proposes a cumulative damage assessment framework for a transmission tower-line system under long-term wind loads from a holistic and dynamic spatiotemporal perspective. The joint probability distribution of wind speed and direction is obtained employing Copulas. Based on Miner rule, the damage resistance surface of the system under overall wind vectors is established by the rain-flow method. Joint probability distribution and damage resistance surface were utilized to introduce the damage risk of the system and derive its mathematical expression. Applying this framework, the overall damage risk of a service tower-line system designed in the 1990s was evaluated, and its life was predicted. The results indicate that Weibull and von Mises are suitable models for wind speed and direction marginal distributions in Linyi. The Gumbel copula was the best of five copula functions. The proposed damage resistance surface effectively reflects the damage resistance capacity of the element. The damage risk framework comprehensively captures the status of the system, enhancing life predictions. The tower-line system comprises multiple elements with similar high damage rather than just one or a few. During maintenance, comprehensive reinforcement should focus on locations with high damage risks to ensure the long-term safe service of the transmission lines.