Development of a Safety Assessment Framework for Fixed-Type Offshore Wind Power Facilities Using AHP-FMEA Methodology

Abstract

Fixed-type offshore wind power facilities operate under harsh marine conditions—salinity, corrosion, combined wave and current loading, and severe access restrictions—that increase the likelihood of component failure while making periodic inspection and maintenance difficult and costly. Conventional Failure Mode and Effects Analysis (FMEA) based on the Risk Priority Number (RPN) evaluates failure modes only at the component level and cannot reflect the relative importance of higher-level subsystems, which biases the risk ranking toward frequently occurring failures. This paper proposes a two-stage hybrid safety assessment framework that combines the Analytic Hierarchy Process (AHP) with RPN-based FMEA. A component classification aligned with the inspection and diagnostic capability of an electrical safety authority is first derived, comprising four major categories, fifteen sub-elements, and eighty-one failure modes. AHP assigns relative weights to the four top-level categories, while a marine-adapted seven-point RPN scheme evaluates each failure mode; the two are combined into a Weighted Risk Priority Index (WRPI) on a 100-point scale. Both the pairwise comparisons and the S–O–D ratings were elicited from a panel of six field-inspection experts of an electrical safety authority, covering the electrical, civil and mechanical disciplines. The AHP analysis yields the highest weight for electrical facilities (0.565), followed by wind facilities (0.262), the SCADA system (0.118) and the civil foundation (0.055), with a consistency ratio of 0.043. The resulting WRPI ranking shows closer qualitative agreement with published wind-turbine accident statistics than either a raw-RPN ranking or an equally weighted single-stage FMEA, and the framework is expected to support the prioritization of inspection items for future SCADA-based remote assessment.