Emergency power supply device

[0001] 1. Field of the Invention

[0002] 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.

[0003] 2. Description of the Related Art

[0004] 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 out of the wind, in which case, lead accumulators may also be used as an emergency power supply device to accomplish this task.

[0005] 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.

[0006] Elektrizittswirtschaft, 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] In the drawings, the sizes and relative positions of elements are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are enlarged and positioned to improve drawing legibility.

[0011] FIG. 1 is a diagram showing the basic circuitry, according to the principals of the present invention, for providing emergency power to adjust the rotor blades of a wind power installation.

[0012] According to the principles of the present invention, a capacitor is used to provide electrical energy to a wind power installation and thereby perform various functions.

[0013] The particular advantage of capacitors lies in the freedom from maintenance and the unlimited number of charging and discharging processes, in contrast to conventional accumulators or batteries.

[0014] Particularly suitable for this purpose is a capacitor produced by Siemens Matsushita Components GmbH & Co KG under the name UltraCap and article No B48710-A0283-Q035. That capacitor has the following technical data:

	(Nominal) capacitance CR	2.8	F
	(DCC(1), 25 C.):
	Capacitance tolerance:	10 . . . 30%
	(Nominal) voltage UR	75	V
	Output(2)	578	W/kg	765 W/l
	Max. charging/discharging	25	A
	current Ic (25 C.)
	Stored energy (at UR)	7875	J
	Specific energy (at UR)	1.09	Wh/kg	1.43 Wh/l
	Surge voltage	88	V
	Max. leakage current ILC	4	mA
	(12 h, 25 C.)
	Max. series resistance ESRDC	800	m
	(DCC, 25 C.
	Max. series resistance ESRHF	480	m
	(1 kHz, 25 C.)
	Weight	2	kg
	Volume	1.5	l
	Operating temperature	25 . . . 65 C.
	Storage temperature	35 . . . 65 C.
	Service life (25 C., UR)	180,000	h
	Height width length	70 70 312 mm
	(1)DCC: discharge at constant current
	(2)discharge of UR after UR/2 with IC 25 A.

[0015] FIG. 1 shows the basic diagram for using one or more capactors 10 to adjust the rotor blades of a wind power installation. In this example, the rotor of the wind power installation has three rotor blades (not shown) and each individual rotor blade can be set (regulated) to a desired pitch angle via an adjusting motor 12 (A, B or C) couplable to each individual rotor blade. Each adjusting motor 12 may be controlled by way of a respective relay 14, (A, B or C).

[0016] A blade regulating device 16 (A, B or C) is positioned adjacent to the motor 12 and coupled to the capacitor 10. Via relay 14, the blade regulating device 16 receives its values from a control unit 18 (control cabinet). In the event of an emergency shut-down, which may be caused, for example, by a short-circuit in either the wind power installation the power supply device,, the blade regulating device 16 effects a blade adjustment which turns each rotor blade out of the wind, so that the rotor blades no longer produce any drive to the rotor.

[0017] The energy required by each blade regulating device 16 is provided by a capacitor 10 (in this example, CA, CB and CC). The capacitors 10 are provided with a connection (not shown) to the generator of the wind power installation so that during the normal operation of a wind power installation, the capacitors 10 receive a charge. In this way, the capacitors 10 are always prepared to provide a sufficient amount of energy to set the rotor blades to a desired pitch angle if necessary. Since the capacitors 10 have a very small design configuration, they can be positioned directly at the adjusting motors and can also be held by them. However, it is also possible for all capacitors 10 to be positioned together in their own accommodation and, if necessary, to be switched on as the emergency power supply device for rotor blade adjustment or for other parts of the wind power installation (for example for alarm lighting or hazard lights).

[0018] Although a single capacitor may be used, it is advantageous to provide a plurality of capacitors connected in parallel so that a sufficient emergency power capacity can always be made available.

[0019] All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety.

[0020] From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.