Patent Application
20150084439
The present disclosure is directed to wind turbine power supplies, and more particularly to shorting devices, shorting assemblies and methods for shorting wind turbine power supplies.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
In many instances, it may be desirable to stop the generator from operating or being capable of operating. For example, during routine maintenance or repairs, it is desirable to “lock out” the generator using a “lock out tag out” procedure to ensure that the generator does not injure a worker. Presently known procedures for locking out a generator, however, are cumbersome and time consuming. For example, workers are currently required to climb the wind turbine tower to access the generator in the nacelle directly. After climbing the wind tower, the workers can apply a rotor lock pin into the generator's shaft, to physically prevent spinning, or can apply locks to a generator in-line circuit breaker after visually verifying that the breaker contacts are open. Because they require workers to climb the wind turbine tower and directly access the generator, however, such procedures increase labor costs and wind turbine downtime, and can increase safety risks to the workers.
Accordingly, improved methods and apparatus for locking out wind turbine generators are desired in the art. In particular, methods and apparatus that increase worker safety while reducing labor costs and wind turbine downtime are desired.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one embodiment, a shorting assembly for a wind turbine power supply is disclosed. The shorting assembly includes a generator, and a plurality of bus bars in electrical communication with and disposed downstream of the generator. The shorting assembly further includes a shorting device removably connectable to the plurality of bus bars. The shorting device includes a plurality of cables, each of the plurality of cables including a first end and a second end. The shorting device further includes a plurality of bus bar connectors, each of the plurality of bus bar connectors attached to the first end of one of the plurality of cables and removably connectable to one of the plurality of bus bars. The shorting device further includes a common cable connector, the second end of each of the plurality of cable attached to the common cable connector.
In another embodiment, a shorting device for shorting a power supply, the power supply including a generator and a plurality of bus bars downstream of the generator, is disclosed. The shorting device includes a plurality of cables, each of the plurality of cables including a first end and a second end. The shorting device further includes a plurality of bus bar connectors, each of the plurality of bus bar connectors attached to the first end of one of the plurality of cables and removably connectable to one of the plurality of bus bars. The shorting device further includes a common cable connector, the second end of each of the plurality of cable attached to the common cable connector.
In another embodiment, a method for shorting a wind turbine power supply is disclosed. The method includes locating a plurality of bus bars, the plurality of bus bars in electrical communication with a generator of the wind turbine power supply and disposed in a downtower location. The method further includes connecting the plurality of bus bars to a common shorting component.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Referring now to
Generator 52 may be coupled to a power converter 54. The power converter 54 may be in electrical communication with and disposed downstream (relative to the flow of electrical power) of the generator 52. Output multiphase power, such as for example three-phase power, may be supplied from the generator 52, such as from the rotor of the generator 52, to the power converter 54. Specifically, generator 52 may be coupled to a rotor side converter 56 of the power converter 54. The rotor side converter 56 may in turn be coupled to a line side converter 58 of the converter 54. After being supplied to the converter 54 from the generator 52, power may flow to the grid. Additionally, in some embodiments, a main generator circuit breaker 60 may be provided between the generator 52 and the power converter 54, as shown.
Referring still to
Referring still to
In some embodiments, a ground ball stud 80 may additionally be provided. The ground ball stud 80 may be similar to a ball stud 74, and may include a ball end 82, but may not be connected to and extending from a bus bar 72. Rather, a ground ball stud 80 may be connected to the cabinet 70 or another suitable location for establishing a voltage reference to ground potential.
As discussed above, improved apparatus for locking out the generator 52 are desired in the art. Accordingly, and referring now to
A shorting assembly 100 may further include a shorting device 102. The shorting device 102 may be utilized to short the wind turbine 10 power supply 50. Advantageously, use of shorting devices 102 according to the present disclosure may increase worker safety while reducing labor costs and wind turbine downtime, by allowing worker to short the power supply 50 at downtower locations 64.
As shown, a shorting device 102 may include a plurality of cables 110. In exemplary embodiments, three cables 110 may be provided. Generally, the number of cables 110 may for example match the number of bus bars 72. Each cable 110 may include a first end 112 and a second end 114. A cable 110 may be formed from any suitable conductive material, such as for example copper or another suitable metal. In exemplary embodiments, a cable is formed from a braided copper.
A shorting device 102 may further include a plurality of bus bar connectors 120. Each bus bar connector 120 may be attached to the first end 112 of a cable 110, and may be removably connectable to one of the plurality of bus bars 72. Referring to
As mentioned, a bus bar connector 120 may be attached to a first end 112 of a cable 110. For example, referring still to
A shorting device 102 according to the present disclosure may further include a common cable connector 140. The common cable connector 140 may be attached to the second ends 114 of each cable 110 of the shorting device 102. Further, in some embodiments, the common cable connector 140 may be removably connectable to a point of zero electrical potential, such as the cabinet 70 or ground ball stud 80. However, it should be understood that the shorting device 102 need not necessarily be connected to a point of zero electrical potential in order to achieve a shorting effect on the generator. Referring to
As mentioned, the common cable connector 140 may be attached to a second end 114 of each cable 110. For example, referring still to
As mentioned, in some embodiments, the common cable connector 140 need not be connected to a point of zero electrical potential. In these embodiments, the common cable connector 140 still acts as the point of commonality for the shorting device 102 and shorting assembly 100. In other embodiments, the common cable connector 140 may be connected to a ground source, such as discussed above.
Connection of the shorting device 102 to the bus bars 72 may advantageously short the power supply 50, generally preventing the generator 52 from spinning fast enough to create a dangerous voltage level. Such shorting is caused because the various phases of power being generated by the generator 52 are shorted together by the shorting device 102 when the shorting device 102 is connected to each phase through connection to the bus bars 72. When shorted, the generator 52 is prevented from spinning at a relatively high rotational speed, because the shorting device 102 introduces a resistive rotational torque in a direction opposite to the direction in which the generator 102 is spinning.
Further, advantageously, use of a shorting device 102 and shorting assembly 100 according to the present disclosure may increase worker safety while reducing labor costs and wind turbine downtime, because the shorting device 102 can be utilized to short the power supply 50 from a downtower location 64, as discussed herein.
It should be understood that shorting devices 102 according to the present disclosure are not limited to use in wind turbines 10 with wind turbine power supplies 50, but rather that use with any suitable power supply 50 is within the scope and spirit of the present disclosure.
The present disclosure is further directed to methods for shorting a wind turbine power supply 50. A method may include, for example, the step of locating a plurality of bus bars 72. The plurality of bus bars 72 may be in electrical communication with a generator 52 of the wind turbine power supply 50 and disposed in a downtower location 64. A method may further include, for example, connecting the plurality of bus bars 72 to a common shorting component. In exemplary embodiments, for example, such connection may include removably connecting a shorting device 102 to each of the plurality of bus bars 72.
In some embodiments, the generator 52 is disposed in an uptower location 62. Further, in some embodiments, the wind turbine power supply 50 further comprises a converter 54, the converter comprising the plurality of bus bars 72.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
