Das Projekt "Elektrodynamische Bremsen für große Windenergieanlagen" wird vom Umweltbundesamt gefördert und von Germanischer Lloyd Wind Energie durchgeführt. General Information: State of the art Wind turbine currently use a combination of mechanical and aerodynamic braking devices. The mechanical systems tend to be expensive, are subject to mechanical wear and cause impulsive drive train loads which result in additional costs either in design against those loads or in failures. An Electrodynamic Brake (EDB) offers an attractive alternative which has been used in other industries. Garrad Hassan (GH) are leading a preliminary investigation of EDB's on behalf of the UK Department of Trade and Industry. This study has explored the EDB state-of-the-art, the view of the wind turbine industry and the design issues. It has emerged that there is interest in this technology and that a demonstration at large commercial scale is required to allow this approach to gain real credibility. The advantages of EDB's increase with machine size. The application of EDB technology at the proposed size is highly innovative. Objectives - To reduce the impact loads during braking transients by 50 per cent - To reduce the cost of a typical commercial 600 kW wind turbine by 1 per cent - To increase reliability of machine safety systems particularly in developing countries where grid failures are frequent and hence mechanical brake wear is high. These prime objectives will be realised through the achievement of the secondary objectives: - To design, install and operate an electrodynamic braking system for a 600 kw commercial wind turbine. - To evaluate its technical and economic performance compared to a conventional mechanical system. SCOPE The conclusions will be applicable to all wind turbines with a grid connected induction generator-presently the majority of commercial machines. The potential advantages offered by electrodynamic braking are listed below: - Low cost and simplicity. The EDB comprises readily available passive components and is activated by a conventional contractor. There is no requirement for an additional electrical machine-a single conventional induction generator can cover both energy production and braking tasks. - Benign brake torque characteristic. The brake torque characteristic is less severe than that generated by a mechanical friction brake and will therefore cause less gearbox damage. The electrodynamic brake application can be staged with a series of contractors and therefore offers a degree of brake torque control. - No wear. The EDB does not involve mechanical wear of any sort. - Fail-safe operation. The EDB components are all passive. The design can be arranged so that the EDB contactor must be actively held open. The EDB will function with and without a network connection. Micon is interested in employing the EDB to enable smoother, oscillation free transitions between low and high generator speeds. If drive train oscillations are significantly reduced then a cheaper main shaft construction may be possible. ... Prime Contractor: Micon A/S, Research and Development; Randers; Denmark.