A cross section of the AW3000, shows some internal components. 1. Rotor Blades 2. Hub 3. Control System Monitoring 4. Main Shaft 5. Gearbox 6. Disk Brake 7. Generator Coupling 8. Cooling Radiator 9. Wind Measuring System 10. Generator 11. Yaw Drive 12. Hydraulic System 13. Yaw Bearing 14. Tower
Acciona Windpower’s AW3000/116 improves on its predecessor with several features, one of which is a larger rotor to suit less windy sites. The 3-MW model sports a 116-m rotor diameter and is certified for application at IEC Class IIA locations—those with medium wind speeds.
But that doesn’t mean the turbine can’t perform well at low wind speeds, too. Its manufacturer says the model delivers a power curve that yields high capacity factors at almost any site. Options for 92-m steel or 120-m concrete towers also increase the turbine’s versatility. Such taller towers let the AW 3000/116 reach a better wind resource higher up, giving even average wind-speed sites a competitive advantage. Furthermore, the company’s concrete towers can be constructed onsite using a mobile concrete batch plant. This reduces transportation costs while increasing use of local content and labor.
Other specs include: Hub Height: Steel (92m), Concrete (100 or 120m); Gearbox: 3 stages-2 planetary, 1 parallel (helical); Generator: 6 poles, double feeding
The 3-MW turbine’s large nameplate rating also helps cut costs. A wind project that uses 3-MW turbines versus 1.5-MW turbines requires fewer foundations, roads, and less balance of plant infrastructure. Acciona says these savings can add up to more than 15% of the balance-of-plant costs of a typical project. The AW3000 was also designed with transportation in mind as there are four possibilities for transporting the nacelle, including shipping in pieces and on rail.
Also, while competing models generate at 690V, the AW3000 generates at 12,000V. This may eliminate the use of a step-up transformer in smaller projects, which cuts down on energy losses and reduces maintenance costs. Acciona says this can result in up to 50% savings in collection system costs and 1% greater wind energy production.
Furthermore, the OEM says the AW3000 is high-tech and grid friendly. It has zero voltage ride-through beyond current regulatory requirements, in addition to centralized voltage control which ensure seamless grid integration in even the most stringent interconnect locations. Control software also allows automatic monitoring and operation.
Reliability is the main feature of the turbine design. Double bearing support on the turbine’s main shaft reduces bending loads on the gearbox. Hydraulic pitch controls allow safe and reliable blade pitching in all wind conditions. The medium voltage (12kV) generator implements a 6 pole design, reducing the speed in the high speed shaft by about 18%.
Safety is also an important part of the turbine design. Roomier and simpler layout provides a more friendly and spacious work environment for working in the nacelle. Direct access to the hub from the nacelle and a standard two-person service lift are additional key safety features.
Due to the 12-kV generator, electrical installation is simpler, eliminating low/medium voltage electrical equipment such as intermediate step up transformers, which in turn reduces the risk of electrical hazards.
While other turbines generate 690V, Acciona’s design generates 12,000V which eliminates a step-up transformer. This results in significant savings over the project’s life, including decreased collection system costs, greater energy production by avoiding transformer electrical losses, and avoiding transformer maintenance and potential failures. The diagram suggests that conventional turbines in the lower row need more electrical equipment than the Acciona (12 kV) models in top row.
Finally, the company stresses the availability and reliability of all its turbines, with an availability of more than 98% across its global fleet and a failure rate of less than 1% on all major components. In 2012, AW3000’s will be installed in Iowa, Poland, and Spain. WPE
Filed Under: Turbines
