Volume 12 Issue 2
Field Demonstration of Real-Time Wind Turbine Foundation Strain Monitoring
Tim Rubert, Marcus Perry, Grzegorz Fusiek, Jack McAlorum, Pawel Niewczas, Amanda Brotherston and David McCallum
1Doctoral Training Centre in Wind and Marine Energy Systems, University of Strathclyde, Glasgow G1 1XQ, UK
2Department of Civil & Environmental Engineering, University of Strathclyde, Glasgow G1 1XJ, UK
3Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow G1 1XQ, UK
4Scottish and Southern Energy (SSE), Glasgow G2 6AY, UK
*Author to whom correspondence should be addressed.
Abstract
Onshore wind turbine foundations are generally over-engineered as their internal stress states are challenging to directly monitor during operation. While there are industry drivers to shift towards more economical foundation designs, making this transition safely will require new monitoring techniques, so that the uncertainties around structural health can be reduced. This paper presents the initial results of a real-time strain monitoring campaign for an operating wind turbine foundation. Selected reinforcement bars were instrumented with metal packaged optical fibre strain sensors prior to concrete casting. In this paper, we outline the sensors’ design, characterisation and installation, and present 67 days of operational data. During this time, measured foundation strains did not exceed 95 μϵ
, and showed a strong correlation with both measured tower displacements and the results of a foundation finite element model. The work demonstrates that real-time foundation monitoring is not only achievable, but that it has the potential to help operators and policymakers quantify the conservatism of their existing design codes.
Keywords:wind turbine foundation; structural health monitoring; finite element model; reinforcement strain; fibre Bragg grating