Method for operating a wind turbine

Patent metadata

Field	Value
Publication number	US-10972029-B2
Application number	US-201716342468-A
Country	US
Kind code	B2
Filing date	Oct 27, 2017
Priority date	Oct 28, 2016
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A method for operating a wind power installation which is connected to a network connection point of an electrical supply network and is intended to produce and feed electrical energy into the electrical supply network, wherein the electrical supply network has a network nominal frequency and is operated at a network frequency, and the wind power installation which comprises an electrical generator with a generator nominal power can be regulated on the basis of the network frequency, comprising the steps of: using the electrical generator to produce an electrical generator power for feeding into the electrical supply network, feeding the electrical generator power or a part of it into the electrical supply network as electrical feed-in power on the basis of the network frequency, wherein, in a first supporting stage, the electrical generator power is reduced on the basis of the network frequency in order to accordingly reduce the electrical feed-in power, and, in a second supporting stage, the electrical feed-in power is reduced such that the electrical feed-in power is less than the electrical generator power.

First claim

The invention claimed is:

1. A method for operating a wind power installation that is connected to a network connection point of an electrical supply network, wherein the wind power installation is configured to produce and provide electrical energy into the electrical supply network, wherein the electrical supply network has a network nominal frequency and is operated at a network frequency, and wherein the wind power installation comprises an electrical generator with a generator nominal power, wherein the electrical generator is configured to be regulated based on the network frequency, the method comprising:
using the electrical generator to produce an electrical generator power for providing into the electrical supply network;
converting the electrical generator power into a first portion; and
providing at least the first portion of the electrical generator power into the electrical supply network as electrical feed-in power based on the network frequency, wherein:
in a first supporting stage, the method comprises:
receiving, from a controller, a fed back signal representative of the network frequency, wherein the electrical generator power is reduced based on the network frequency to reduce the electrical feed-in power, and

in a second supporting stage, the method comprises:
drawing power from the electrical feed-in power to reduce the electrical feed-in power such that the electrical feed-in power is less than the electrical generator power, wherein the second supporting stage is implemented after the first supporting stage has been completed.

2. The method as claimed in claim 1 , wherein in the second supporting stage, the electrical feed-in power is reduced if the network frequency changes with a frequency gradient which exceeds a predetermined limiting gradient.

3. The method as claimed in claim 1 , wherein in the second supporting stage, the electrical feed-in power is reduced if the network frequency is above a predetermined frequency value.

4. The method as claimed in claim 1 , wherein in the second supporting stage, the electrical feed-in power is reduced if the electrical feed-in power is above a particular power for a predetermined period or exceeds a predetermined power value.

5. The method as claimed in claim 1 , wherein in the second supporting stage, the electrical feed-in power is reduced if the second supporting stage is requested by an operator.

6. The method as claimed in claim 1 , wherein the second supporting stage is implemented independently of the first supporting stage.

7. The method as claimed in claim 1 , wherein the electrical generator power is produced using the electrical generator based on a deviation of the network frequency from the network nominal frequency, wherein the electrical generator power is reduced if the network frequency is above a predetermined desired frequency.

8. The method as claimed in claim 1 , wherein the electrical feed-in power is reduced such that the electrical feed-in power is equal to zero.

9. The method as claimed in claim 1 , further comprising:
removing electrical power from the electrical supply network if the network frequency changes with a frequency gradient that exceeds a predetermined limiting gradient and/or the network frequency is above a predetermined frequency value.

10. The method as claimed in claim 9 , wherein the predetermined limiting gradient is at least one of:
0.5 Hz per second;
between 0.5 Hz per second and 2 Hz per second; and
2 Hz per second.

11. The method as claimed in claim 1 , wherein the electrical feed-in power is reduced in the second supporting stage such that the electrical feed-in power is equal to the electrical generator power if the network frequency changes with a frequency gradient which undershoots a predetermined limiting gradient.

12. The method as claimed in claim 1 , wherein the reduction of the electrical feed-in power in the second supporting stage comprises consuming electrical power chosen from at least one of the electrical generator power and electrical power from the electrical supply network, wherein the consuming comprises using a switching device for converting the electrical power into thermal power.

13. The method as claimed in claim 12 , wherein the switching device for converting electrical power into the thermal power is configured to convert electrical power corresponding to the generator nominal power into the thermal power for at least three seconds.

14. The method as claimed in claim 12 , wherein the switching device for converting electrical power into the thermal power is configured to convert electrical power corresponding to twice the generator nominal power into the thermal power for at least three seconds.

15. The method as claimed in claim 12 , wherein the switching device comprises at least one chopper.

16. The method as claimed in claim 12 , wherein the switching device is a chopper bank.

17. The method as claimed in claim 1 comprising:
converting electrical power that is removed from the electrical supply network to support the network frequency of the electrical supply network if the network frequency changes with a frequency gradient which exceeds a predetermined limit value.

18. A wind power installation, comprising:
an electrical generator with a generator nominal power for producing electrical generator power, wherein the wind power installation is configured to convert the electrical generator power into a first portion, and the wind power installation is configured to be connected to a network connection point of an electrical supply network to provide the first at least the portion of the electrical generator power into the electrical supply network as an electrical feed-in power based on a network frequency of the electrical supply network;
a rectifier coupled to an output of the electrical generator;
a direct current (DC) intermediate circuit coupled to an output of the rectifier;
an inverter coupled to an output of the DC intermediate circuit; and
a switching device, coupled to the DC intermediate circuit and an output of the inverter, configured to:
in a first supporting stage, receive, from a controller, a fed back signal representative of the network frequency, and reduce the electrical generator power based on the network frequency to reduce the electrical feed-in power, and
in a second supporting stage, draw power from the electrical feed-in power to reduce the electrical feed-in power such that the electrical feed-in power is less than the electrical generator power, wherein the second supporting stage is implemented after the first supporting stage has been completed.

19. The wind power installation as claimed in claim 18 , wherein the switching device is configured to convert the electrical feed-in power into thermal power, wherein the switching device is configured to consume at least part of the electrical generator power to reduce the electrical feed-in power.

20. The wind power installation as claimed in claim 19 , wherein the switching device is configured to convert electrical power corresponding to the generator nominal power into the thermal power for at least three seconds.

21. The wind power installation as claimed in claim 19 , wherein the switching device is a chopper bank and comprises a rectifier.

22. A wind farm comprising:
a plurality of wind power installations, wherein at least one wind power installation of the plurality of wind power installations is the wind power installation as

Assignees

• Wobben Properties Gmbh

Inventors

• Busker Kai
• Mackensen Ingo
• Brombach Johannes
• Quitmann Eckard
• Emanuel Hanna
• Schellschmidt Martin

Classifications

• H02J2101/28

  Wind energy · CPC title

• Y02E10/76

  Power conversion electric or electronic aspects · CPC title

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title

• H02P9/105 Primary

  for increasing the stability · CPC title

• H02J3/46

  Controlling the sharing of generated power between the generators, sources or networks · CPC title