Reliability Analysis of Offshore Wind Structures Considering the Korean Met-Ocean Conditions

Abstract

IEC and DNV documents, which are developed for the design of offshore wind turbines, have been developed based on the experiences of the offshore wind industry. Moreover, IEC and DNV documents adopt the reliability design method, a partial safety factor based on the limit state design. However, since these documents were developed under European met-ocean conditions, it is necessary to develop a reliability design method suitable for the Korean met-ocean conditions to satisfy the safety level required by overseas documents. Thus, this paper conducted the reliability analysis of offshore wind structures considering the Korean met-ocean conditions. The Monte Carlo Simulation method was used as a reliability analysis technique. Moreover, design variables such as waves and winds of the Korean west sea were calculated by numerical simulation, and design parameters were estimated using extreme analysis. In addition, partial safety factors were suggested to satisfy the target reliability required by IEC. As a result, in the case of the Korean west sea, where typhoons are dominant, the reliability index was calculated lower than in Europe due to the higher variation of design variables such as wind. These results showed that a more careful approach should be taken to installing offshore wind turbines in areas affected by typhoons. Furthermore, it is judged that it is necessary to calibrate the partial safety factors considering the met-ocean conditions of the specific sites.