Demonstrating a Tidal Turbine Control Strategy at Laboratory Scale

Harrold, Magnus; Bromley, Peter T.; Broudic, Merin; Clelland, David

doi:10.1115/omae2016-54364

Cited by 4 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Better control of the tip speed ratio could have been achieved by changing the gain applied to the generator torque in a variable speed turbine control scheme, but this functionality was not possible at the time of testing. However, the results from previous testing of this rotor at model scale using the same RPM stepping method proved to very repeatable [17].…”

Section: Turbine Operationmentioning

confidence: 85%

“…The adoption of this overspeed control strategy removed the requirement for an active pitch system, ensuring that the number of sub-systems and failure modes were minimised for this first-of-kind device. Validation of the design was achieved through detailed numerical modelling [4,16] and subsequent verification from scale-model testing [17], while the overspeed philosophy has also received recent interest elsewhere [18,19]. It is worth noting that power regulation on fixed-pitch rotors is generally achieved through stall control, whereby the rotor is slowed to a lower λ.…”

Section: Designed Rotor Characteristicsmentioning

confidence: 99%

“…This procedure for calculating thrust differs from that typically used in scale-model studies [17] or field testing of smaller rotors [12], where load cells are placed on the turbine support structure and a correction is applied to remove the drag forces acting on the structural elements, leaving only the axial force on the rotor. This involves measuring the drag on the support structure without the rotor, something that was not practical for the turbine in this study and would not provide any information on the individual blade loading and bending moments.…”

Section: Instrumentationmentioning

confidence: 99%

“…Provided that each step change was not accompanied by a proportional change in mean flow speed, the turbine would operate at a different tip speed ratio. This procedure is akin to methodologies adopted in scale-model test studies of tidal turbines [17,29]. Figure 11 shows the time-series of approach flow velocity (U 0 ), turbine rotational speed (Ω), tip speed ratio (λ), and blade root bending moment (M y root ) from a test that took place during an ebb tide, with all values representing 10 s averages.…”

Section: Turbine Operationmentioning

confidence: 99%

See 3 more Smart Citations

Rotor Loading Characteristics of a Full-Scale Tidal Turbine

Harrold

Ouro

2019

Energies

Self Cite

View full text Add to dashboard Cite

Tidal turbines are subject to highly dynamic mechanical loading through operation in some of the most energetic waters. If these loads cannot be accurately quantified at the design stage, turbine developers run the risk of a major failure, or must choose to conservatively over-engineer the device at additional cost. Both of these scenarios have consequences on the expected return from the project. Despite an extensive amount of research on the mechanical loading of model scale tidal turbines, very little is known from full-scale devices operating in real sea conditions. This paper addresses this by reporting on the rotor loads measured on a 400 kW tidal turbine. The results obtained during ebb tidal conditions were found to agree well with theoretical predictions of rotor loading, but the measurements during flood were lower than expected. This is believed to be due to a disturbance in the approaching flood flow created by the turbine frame geometry, and, to a lesser extent, the non-typical vertical flow profile during this tidal phase. These findings outline the necessity to quantify the characteristics of the turbulent flows at sea sites during the entire tidal cycle to ensure the long-term integrity of the deployed tidal turbines.

show abstract

Section: Turbine Operationmentioning

confidence: 85%

Section: Designed Rotor Characteristicsmentioning

confidence: 99%

Section: Instrumentationmentioning

confidence: 99%

Section: Turbine Operationmentioning

confidence: 99%

See 2 more Smart Citations

Rotor Loading Characteristics of a Full-Scale Tidal Turbine

Harrold

Ouro

2019

Energies

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ahead of sea deployment, the performance and control strategy of a 1:30scale commercial horizontal axis tidal turbine model was tested [28]. The 0.4m diameter (D) turbine prototype was placed in a 15m long, 1.20m wide and 1.0m deep recirculating flume located in Cardiff University's hydraulics laboratory.…”

Section: Experimental Studymentioning

confidence: 99%

Hydrodynamic loadings on a horizontal axis tidal turbine prototype

Ouro

Harrold²,

Stoesser

et al. 2017

Journal of Fluids and Structures

Self Cite

View full text Add to dashboard Cite

Until recently tidal stream turbine design has been carried out mainly by experimental prototype testing aiming at maximum turbine efficiency. The harsh and highly turbulent environments in which tidal stream turbines operate in poses a design challenge mainly with regards to survivability of the turbine owing to the fact that tidal turbines are exposed to significant intermittent hydrodynamic loads. Credible numerical models can be used as a complement to experiments during the design process of tidal stream turbines. They can provide insights into the hydrodynamics, predict tidal turbine performance and clarify their fluid-structure interaction as well as quantify the hydrodynamic loadings on the rotor. The latter can lead to design enhancements aiming at increased robustness and survivability of the turbine. Physical experiments and complementary large-eddy simulations of flow around a horizontal axis tidal turbine rotor are presented. The goal is to provide details of the hydrodynamics around the rotor, the performance of the turbine and acting hydrodynamic forces on the rotor blades. The simulation results are first compared with the

show abstract

Assessing extreme loads on a tidal turbine using focused wave groups in energetic currents

et al. 2019

View full text Add to dashboard Cite

Tidal stream turbines are subject to large hydrodynamic loads, including those induced by extreme waves. Scale model testing in the laboratory plays an important role in ensuring that full scale tidal turbines are designed and operated in a manner that is appropriate for harsh ocean environments where waves and tidal currents coexist. For the first time, a fully-instrumented scaled tidal turbine is tested in short-duration focused wave groups representative of extreme environmental load cases expected at energetic tidal sites. In this paper, the subsequent variations in rotor-based loads, power and blade root bending moments are reported. These measurements are found to strongly follow the spectral and temporal form of the focused wave conditions, and peak loads and power output are found to exceed current-only values by 85% and 200% respectively. These rotor-averaged values display a high level of repeatability, demonstrating the suitability of focused waves for testing seabed-mounted tidal turbines. Extreme blade loads, which are dependent on angular position relative to wave phase, are captured through rapidly obtained repeat tests. New insight is subsequently gained into loading and response of tidal turbines in extreme sea conditions.

show abstract

Demonstrating a Tidal Turbine Control Strategy at Laboratory Scale

Cited by 4 publications

References 0 publications

Rotor Loading Characteristics of a Full-Scale Tidal Turbine

Rotor Loading Characteristics of a Full-Scale Tidal Turbine

Hydrodynamic loadings on a horizontal axis tidal turbine prototype

Assessing extreme loads on a tidal turbine using focused wave groups in energetic currents

Contact Info

Product

Resources

About