Method and electricity generating installation for stabilizing an electricity distribution network

• US 20100176770A1
• Filed: 12/09/2009
• Published: 07/15/2010
• Est. Priority Date: 12/18/2008
• Status: Active Grant

• Current Assignee: Siemens Gamesa Renewable Energy Service GmbH (Siemens AG)
• Original Assignee: REpower Systems AG (Senvion SE)
• Inventors: Fortmann, Jens
• Granted Patent: US 8,203,318 B2
• Time in Patent Office: Days
• US Class Current: 323/205
• CPC Class Codes: F03D 7/0284 in relation to the state of the electric grid
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 3/1885 using rotating means, e.g. synchronous generators
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/50 Controlling the sharing of the out-of-phase component
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

An electricity generating installation is connected to an electricity distribution network and feeds electrical power into the network via a converter. After detecting a network fault, a stabilization regulator in the installation is activated. The stabilization regulator regulates the voltage of the electrical power as a function of a fed-back voltage signal and has a step-function response that rises over time. After a predetermined time period has elapsed since the activation of the stabilization regulator, the reactive current feed is increased beyond a limit which is provided for normal operation if the network has not stabilized. Accordingly, a converter-fed electricity generating installation, such as a wind energy installation, can help stabilize an electricity distribution network after a network fault.

Claims

1. A method for stabilizing an electricity distribution network, in which an electricity generating installation is connected to the electricity distribution network and feeds electrical power into the electricity distribution network via a converter comprising:

detecting a network fault in the electricity distribution network;

activating a stabilization regulator in the electricity generating installation configured to regulate the voltage of the electrical power as a function of a fed-back voltage signal and whose step-function response is configured to rise over time;

checking whether the voltage has stabilized when a predetermined time period has elapsed since activation of the stabilization regulator; and

increasing a reactive current feed beyond a limit which is provided for normal operation if the voltage has not yet stabilized.

2. The method of claim 1, wherein the reactive current feed is increased beyond the limit which is provided for normal operation by increasing a nominal value for the voltage.

3. The method of claim 1, wherein the reactive current feed is increased beyond the limit which is provided for normal operation by giving priority to feeding in reactive current over feeding in real current.

4. The method of claim 3, wherein an upper limit for a phase angle φ

between current and voltage is raised.

5. The method of claim 3, wherein the electricity generating installation is a wind energy installation having a plurality of rotor blades, and wherein a pitch angle of the rotor blades is varied in parallel with a reduction in real power.

6. The method of claim 2, further comprising:

checking whether the voltage has stabilized when a second predetermined time period has elapsed since increasing the nominal value;

raising an upper limit for a phase angle φ

between current and voltage if the voltage still has not yet stabilized.

7. The method of claim 1, further comprising deactivating the stabilization regulator when an actual value of the voltage exceeds a predetermined threshold.

8. The method of claim 1, wherein the stabilization regulator uses voltage on the a high-voltage side as a reference variable.

9. The method of claim 8, wherein the stabilization regulator uses voltage on a high-voltage side before the occurrence of the network fault or a corresponding lower limit of a voltage band as a nominal value.

14. An electricity generating installation which feeds electrical power via a converter into an electricity distribution network, comprising:

a stabilization regulator whose step-function response rises over time and which is configured to regulate the voltage of the electrical power as a function of a fed-back voltage signal;

a control unit comprising an activation module configured to activate the stabilization regulator after a network fault, a detector configured to check whether the voltage has stabilized after a predetermined time period has elapsed since activation of the stabilization regulator, and an actuating element configured to increase a reactive current fed in beyond a limit which is provided for normal operation if the voltage has not yet stabilized,

wherein the electricity generating installation is configured to perform the method of one of claims 2 to 9.

15. The method of claim 1, wherein the electricity generating installation is a wind energy installation.

10. An electricity generating installation which feeds electrical power via a converter into an electricity distribution network, comprising:

a stabilization regulator whose step-function response rises over time and which is configured to regulate the voltage of the electrical power as a function of a fed-back voltage signal;

a control unit comprising an activation module configured to activate the stabilization regulator after a network fault, a detector configured to check whether the voltage has stabilized after a predetermined time period has elapsed since activation of the stabilization regulator, and

an actuating element configured to increase a reactive current fed in beyond a limit which is provided for normal operation if the voltage has not yet stabilized.

11. The electricity generating installation of claim 10, wherein the stabilization regulator is an I-regulator.

12. The electricity generating installation of claim 10, wherein the stabilization regulator is a P-regulator with time-dependent gain.

13. The electricity generating installation of claim 10, wherein the stabilization regulator is configured to have an exclusively voltage-raising effect.