1. Field of the Invention
The present invention provides a unique arrangement for providing emergency power to a wind power installation, including the use of one or more capacitors as a storage means for electrical energy.
2. Description of the Related Art
In the known prior art, wind power installations emergency power is typically supplied by means of accumulators, in particular lead accumulators, so that in the event of a power failure the wind power installation can be put into a position that avoids damage to the wind power installation. For example, in the event of a power failure, which may occur due to a short-circuit in the power supply system, lead accumulators are used to supply the emergency power needed to adjust the blades of the wind power installation, so that the entire wind power installation rotor may be brought to a stop and thereby no longer experience any substantial drive due to the energy of the wind. In the event of a power failure, it may also be necessary to rotate the wind power installation pod xe2x80x98out of the windxe2x80x99, in which case, lead accumulators may also be used as an emergency power supply device to accomplish this task.
However, the disadvantage of lead accumulators is that they are relatively heavy, they take up a great deal of space and, since lead accumulators cannot be charged and discharged an unlimited number of times, the charging and discharging properties of the lead accumulators deteriorate with time. In addition, the storage of a lead accumulator requires relatively high maintenance costs and thereby increases the costs of a wind power installation and operation.
Elektrizitxc3xa4tswirtschaft, volume 1994 (1995), issue 14, pages 842 through 845, disclose various power storage arrangements for supplying energy. Also set forth therein are electrical storage means which are used in generating plants, apart from their function as an emergency power supply, for load compensation purposes and for providing seconds reserves whereby the utilization duration of the energy-generating installations is improved. Double-layer capacitors are also mentioned in this connection.
DE 196 51 364 A1 discloses an apparatus for improving the network compatibility of wind power installations with asynchronous generators, wherein an electronically controlled device, which includes an intermediate energy storage means, is connected in parallel with the public power supply network, and mention is also made of a capacitor as a possible form of the intermediate storage means.
Despite these disclosures, Applicant believes that there is a need for a new and improved arrangement for providing emergency power to a wind power installation and the present invention provides such system.
The present invention provides an improved arrangement for supplying emergency power to a wind power installation. In the event of a power failure, sufficient emergency power may be supplied to reposition the rotor blades of the wind power installation and avoid damage to the overall system. This is done through the use of one or more capacitors. The capacitors may be charged with energy during the normal operation of the wind power installation and, in the event of a system failure, the energy stored within the capacitors may be used to provide emergency functions. In addition to repositioning the rotor blades, the stored energy may be used, for example, to rotate the wind power installation pod away from the wind, and power emergency or auxiliary lighting systems.