Wind turbine having an expanded voltage range

Patent metadata

Field	Value
Publication number	US-2016308368-A1
Application number	US-201414783825-A
Country	US
Kind code	A1
Filing date	Mar 13, 2014
Priority date	Apr 9, 2013
Publication date	Oct 20, 2016
Grant date	—

Abstract

A wind turbine having a wind rotor, a generator powered therewith for generating electrical energy, and a connecting line for delivering the electrical energy, optionally via a system transformer. The wind turbine includes a voltage expander that expands the voltage range of the wind turbine by means of an auxiliary voltage source. The voltage expander comprises a small transformer of having a primary and a secondary winding, and a switching mechanism. The small transformer is looped into the connecting line with the secondary winding, and the switching mechanism is connected to the primary winding of the small transformer, actuating the primary winding in a switchable multi-stage manner. Thus, a multi-stage expansion of the voltage range of the wind turbine is achieved, wherein due to the arrangement of the small transformer lengthwise in the connecting line, the small transformer can have a fraction of the nominal power of the wind turbine.

First claim

1 . A wind turbine comprising a wind rotor, a generator driven thereby for generating electrical energy, a connecting line for outputting the electrical energy, and a voltage expander configured to expand the voltage range of the wind turbine using an additional voltage source, wherein the voltage expander comprises a dedicated small transformer comprising a primary and a secondary winding and a switching mechanism and wherein the small transformer is looped in the connecting line with the secondary winding, and the switching mechanism is connected to the primary winding of the small transformer and actuates said primary winding with the capacity for switchover in multi-tap actuation fashion.

2 . The wind turbine of claim 1 , wherein the multi-tap actuation by the switching mechanism takes place with different polarization.

3 . The wind turbine of claim 1 , wherein a plurality of small transformers are arranged in series on the connecting line.

4 . The wind turbine of claim 1 , wherein the small transformer has a power which is at most ¼ of the rated power of the wind turbine.

5 . The wind turbine of claim 4 , wherein the power of the small transformer is dimensioned such that it is proportional to the additional voltage.

6 . The wind turbine of claim 1 , wherein the voltage expander is disconnectable from the connecting line via switching contactors.

7 . The wind turbine of claim 1 , wherein the switching mechanism has a load tap, which is connected during switchover so that the small transformer is always connected to a load.

8 . The wind turbine of claim 1 , wherein the voltage expander is connected on a high-voltage side to a turbine transformer.

9 . The wind turbine of claim 8 , wherein the small transformer is connected within a medium-voltage winding of the turbine transformer.

10 . The wind turbine of claim 8 , wherein the small transformer is connected on a medium-voltage side at a neutral point of the turbine transformer.

11 . The wind turbine of claim 9 , wherein the small transformer is in the form of a high-leakage-reactance transformer, which has a short-circuit voltage uk of at least 0.10.

12 . The wind turbine of claim 11 , wherein the high-leakage-reactance transformer has magnetic steel sheets with a hard saturation characteristic.

13 . The wind turbine of claim 11 , wherein the primary winding of the small transformer is wound over the secondary winding thereof.

14 . The wind turbine of claim 11 , wherein the high-leakage-reactance transformer is provided with pancake coils.

15 . The wind turbine of claim 1 , wherein the switching mechanism is actuated depending on at least one of voltage and wattless power.

16 . The wind turbine of claim 15 , comprising a regulator for the at least one of voltage and wattless power, wherein the regulator is configured to detect, as controlled variable, the at least one of voltage and wattless power in the connecting line.

17 . The wind turbine of claim 16 , wherein the voltage expander interacts with disturbance variable feedforward control for the regulator.

18 . A wind farm comprising a plurality of wind turbines, which are connected to a farm grid, which is connected to a transmission grid via a coupling line, and a central voltage expander configured to expand the voltage range of the wind farm using an additional voltage source, wherein the additional voltage source comprises a small transformer comprising a primary winding and a secondary winding and a switching mechanism, and wherein the small transformer is looped in the coupling line with the secondary winding, and the switching mechanism is connected to the primary winding of the small transformer and actuates said primary winding with the capacity for switchover in multi-tap actuation fashion.

19 . The wind farm of claim 18 , comprising a farm regulator for at least one of voltage and wattless power, wherein the farm regulator is configured to detect, as controlled variable, the at least one of voltage and wattless power in the coupling line.

20 . The wind farm of claim 19 , wherein the voltage expander interacts with disturbance variable feedforward control for a farm regulator.

21 . (canceled)

22 . The wind turbine of claim 3 , wherein a dedicated switching mechanism is provided for each of the plurality of small transformers.

23 . The wind turbine of claim 5 , wherein the power of the small transformer is at most a tenth of the rated power of the wind turbine in the case of an additional voltage of the order of a tenth of the rated voltage.

24 . The wind turbine of claim 8 , wherein the voltage expander is connected within a medium-voltage winding of the turbine transformer.

25 . The wind turbine of claim 9 , wherein the small transformer is in the form of a high-leakage-reactance transformer, which has a short-circuit voltage uk of at least 0.15.

26 . The wind turbine of claim 14 , wherein the pancake coils are arranged on remote limbs of a transformer core and are in the form of webs in the transformer core.

27 . The wind turbine of claim 14 , wherein the pancake coils are arranged on remote limbs of a transformer core or are in the form of webs in the transformer core.

28 . The wind turbine of claim 16 , wherein the regulator is configured to detect, as controlled variable, the at least one of voltage and wattless power in the connecting line on the side of the voltage expander which is remote from the wind turbine.

29 . The wind farm of claim 19 , wherein the farm regulator is configured to detect, as controlled variable, the at least one of voltage and wattless power in the coupling line on the side of the voltage expander which is remote from the farm.

Assignees

• Senvion Gmbh

Inventors

• Letas Heinz-Hermann

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02J3/16

  by adjustment of reactive power · CPC title

• H02J3/14

  by switching loads on to, or off from, the networks, e.g. progressively balanced loading · CPC title

• H02J3/386 Primary

  Electricity · mapped topic

• H02J3/12 Primary

  Arrangements for adjusting voltage in AC networks by changing a characteristic of the network load · CPC title