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- Category: Articles
Reliable Verification of Design Parameters at Prototype and Serial Turbines
For reasons of cost reduction, modern large wind turbines and blades are designed to use less material and to make use of new materials. They are designed using new simulation tools and smaller safety factors, going beyond established knowledge. Therefore, turbine type certification requires simulation validation by real-life prototype measurements to prove that design dimensions (e.g. clearance between blade tip and tower), parameters and assumptions assure safe operation during the planned service life. For safe and reliable operation, every serial turbine also has to comply with certified design parameters. This keeps O&M costs and lifetime consumption low, despite unmanned 24/7 operation in remote areas. Hence, highly accurate but also cost efficient and safe measuring methods are needed to avoid excess fatigue loads, such as those from resonance issues related to the tower’s natural frequencies or intolerably high rotor imbalance and blade angle deviation. For these applications, video-based analysis is a suitable method to measure motion and vibration.
By Anke Grunwald, Christoph Heilmann and Michael Melsheimer, BerlinWind GmbH, Germany
- Category: Articles
Assessing Long-Term Hub Height Wind Specifications
Numerous wind energy yield assessments are based on measurements carried out with a met mast located at a lower height than the hub of the planned wind turbine. This article deals with the issue of vertical extrapolation of measured wind characteristics. It benchmarks four distinct empirical extrapolation methods based on a simple measurement set-up – two heights of anemometers, a wind vane, a short-term measurement of a remote sensing device (lidar, sodar) and different assumptions about the wind shear (α). These methods were tested on nine of Maïa Eolis’ 80-metre met masts in France and benchmarked to a WAsP calculation.
By Olivier Coupiac, Maïa Eolis, France
- Category: Articles
First Reference to Help Ensure Decisions are Rational and Unbiased
The Top 30 Wind Turbine Faults chart is a database of the most significant failure mechanisms, identified through a failure modes and effects analysis (FMEA), which is validated and regularly updated using information available in the public domain and Lloyd’s Register’s experience of working with wind farm operators. This provides a basis for intelligent decision-making during new product design, sensor selection, configuration of condition monitoring software, SCADA specification, O&M management specification and O&M task prioritisation.
By Mark Spring, Senior Wind Loading Specialist, Lloyd’s Register, UK
- Category: Articles
The Multiple Facets of this Subject, Challenges and Latest Advances
Noise is one of the environmental impacts of a wind farm that requires attention, and can in some cases represent a key constraint on the farm’s operation. Regulation and therefore control of this noise has tended to focus on the level or ‘loudness’ of the noise, which is challenging in itself to measure. But recently increasing attention has been given to features in the noise (in other words its character). Objective measures of these aspects have been developed but they still require careful and time-consuming analysis. Advances in the capabilities of sound measuring equipment are, however, helping practitioners and wind farm operators to obtain results more directly.
By Matthew Cand, Executive Acoustic Engineer, Hoare Lea Acoustics, UK
- Category: Articles
A Pathway to a New Offshore Wind Business Model
Numerous organisations and agencies are focused on offshore wind cost reduction initiatives throughout the life cycle and across the supply chain but few are focused on the issue of installation. Capacity will have to increase three-fold to meet even the most conservative of 2050 estimates for offshore wind energy needs. While significant cost reduction is a big prize, it and the problem of lack of construction capacity will not be solved without major change, unless there is massive expenditure on installation vessels. However, as projects are risk averse and resistant to change and the industry is capital intensive, the risk of major change is not one that projects are keen to bear. For them, minor change is preferable. This article sets out how a pathway to major change can help the industry mature and reach its potential.
By Matt Bleasdale, Director, OWLC, UK
- Category: Articles
The Blade Way Concept
During the past few years the market for servicing existing wind turbines has grown rapidly. One of the more significant market segments is for exchanging blades. Commonly, large mobile cranes are used, together with a blade yoke. The costs associated with the use of a crane are high, and so cheaper solutions are being sought.
By Per Fenger and Ruben Tjell Lambertsen, Liftra, Denmark
- Category: Articles
Advanced Modelling Makes This Possible Without Compromising Safety
Unlike wind turbine towers and rotors, which are fabricated under controlled conditions, in general foundations must be tailor-made. This is because soil conditions (hard or soft) and available space dictate the solutions for the foundation. However, the perception is that optimisation of foundation designs leads to higher risk. Maybe due to this the average foundation designer takes a simple, conservative and conventional design approach. But a client should look at things in a different way. Saving money is one thing, saving materials and reducing CO2 emissions is another. A client should aim to have an optimised design. The skills and experience are available and have shown that substantial design optimisations are possible, without increasing risks.
By Axel Jacobs, Civil Consultant Wind Energy, ABT, The Netherlands
