Failure Risk of 230 kV Electricity Transmission Lines in South Carolina under Hurricane Wind Hazards

Abstract

High wind events such as hurricanes are one of the leading causes of electricity transmission line failures. There are two main failure mechanisms associated with de-energized transmission systems during hurricanes: 1) failure of the super-structures or the support towers; and 2) breakage of the transmission lines due to extreme wind loads. This paper presents a methodology for analyzing the reliability of spatially distributed transmission lines under hurricane wind hazard. As a case study, the vulnerability of the spatially distributed 230kv transmission lines in south Carolina was analyzed using 40,000 years of simulated hurricane events. Since the response of transmission lines under wind loads is highly nonlinear, a simplified nonlinear analytical model, verified by a 3-dimentional finite element model, was developed to simulate the tension forces considering the geometric nonlinearity induced by the sagging of the transmission lines. The reliability analysis results are presented in a GIS map, which can be easily used in pre-hurricane planning by power companies.