Conceptual Study of a Real-Time Hybrid Simulation Framework for Monopile Offshore Wind Turbines Under Wind and Wave Loads

Abstract

As an attractive renewable energy source, offshore wind plants are becoming increasingly popular for energy production. However, the performance assessment of offshore wind turbine (OWT) structure is a challenging task due to the combined wind-wave loading and difficulties in reproducing such loading conditions in laboratory. Real-time hybrid simulation (RTHS), combining physical testing and numerical simulation in real-time, offers a new venue to study the structural behavior of OWTs. It overcomes the scaling incompatibilities in OWT scaled model testing by replacing the rotor components with an actuation system, driven by an aerodynamic simulation tool running in real-time. In this study, a RTHS framework for monopile OWTs is proposed. A set of sensitivity analyses is carried out to evaluate the feasibility of this RTHS framework and determine possible tolerances on its design. By simulating different scaling laws and possible error contributors (delays and noises) in the proposed framework, the sensitivity of the OWT responses to these parameters are quantified. An example using a National Renewable Energy Lab (NREL) 5-MW reference OWT system at 1:25 scale is simulated in this study to demonstrate the proposed RTHS framework and sensitivity analyses. Three different scaling laws are considered. The sensitivity results show that the delays in the RTHS framework significantly impact the performance on the response evaluation, higher than the impact of noises. The proposed framework and sensitivity analyses presented in this study provides important information for future implementation and further development of the RTHS technology for similar marine structures.

Seismic behaviour analysis of a wind turbine tower affected by sea ice based on a simplified model

“…Before derivation of similar formulas, we make the following assumptions: In the shaking-table tests on interplays among ice, structure, and water, it is ideal when the model and prototype structures satisfy similarity relationships in terms of gravity, inertial force, and resilience; whereas, there are strict requirements on density and elasticity modulus of structural materials. Hence, researchers generally use a similarity law of elastic force-gravity when performing the tests, to ensure consistency of the Cauchy constant and Froude constant in prototype and tested structures 27 .…”

Reinforcement learning control method for real‐time hybrid simulation based on deep deterministic policy gradient algorithm

“…1 Hence, it is essential to investigate the responses of large-scale and complicated engineering structures, such as bridges and tall buildings, subjected to extreme multi-hazard effects. According to previous research, scholars have dedicated themselves to RTHS for (i) external effects analysis, such as seismic, wave, fire, and current effects, [2][3][4][5][6] and (ii) various applications of structural components and control methods for nonlinear behavior of complicated systems and environment interactions, especially when subjected to aleatory uncertainties. [7][8][9][10] An RTHS is usually set up with two types of hydraulic loading facilities: an actuator and a shaking table.…”

Reproduction of seismic responses of wind turbine tower by hybrid tests considering shear and bending coupled boundary control

“…Recent studies (Chabaud et al 2018; Hall et al 2018; Sauder et al 2016; Thys et al, 2018) have adopted the wind tower as the physical substructure, and the aerodynamic loads have been calculated in the numerical substructure and imposed on the top of the physical substructure by cable-driven parallel robots or a rotor-coordinate transformation frame system. Similarly, Song et al (2020) proposed the testing of the lower substructure of a monopile offshore wind turbine using actuators to impose the aerodynamic force on the physical substructure.…”