Defined switch position in a wind farm prior to failure of the DC power supply

Abstract

A method for controlling a wind power installation or a wind farm is provided. The method includes establishing that there is a grid fault within an electrical power supply grid operated by a grid operator and to which the wind power installation or the wind farm is electrically connected via a point of common coupling; switching electrical switches of the wind power installation or the wind farm using a control unit of the wind power installation or the wind farm which is operated by a low-voltage power supply, so that the wind power installation or the wind farm is voltage-free; testing an electrical store for ensuring the low-voltage power supply once the grid fault has been established; and switching further electrical switches of the wind power installation or the wind farm to a predefined switching state in which start-up of the wind power installation or the wind farm is possible.

Claims

1. A method for controlling a wind power installation or a wind farm, comprising: determining that a grid fault exists in an electrical power supply grid, wherein the electrical power supply grid is operated by a grid operator, and the wind power installation or the wind farm is electrically connected to the electrical power supply grid via a point of common coupling; switching, by a wind power installation controller or a wind farm controller, a first electrical switch of the wind power installation or the wind farm to cause the wind power installation or the wind farm to be voltage-free, wherein the wind power installation controller or the wind farm controller is operated by a low-voltage power supply; in response to determining that the grid fault exists in the electrical power supply grid, testing an electrical stage device to determine whether the low-voltage power supply is available; and switching a second electrical switch of the wind power installation or the wind farm to a predefined switching state in which start-up of the wind power installation or the wind farm is executable.

2. The method as claimed in claim 1, wherein: the wind power installation is voltage-free when the wind power installation is disconnected from an electrical wind farm grid by using the first electrical switch, wherein the first electrical switch is a first circuit breaker, or the wind farm is voltage-free when the wind farm is disconnected from the electrical power supply grid using the second electrical switch, wherein the second electrical switch is a second circuit breaker.

3. The method as claimed in claim 1, wherein the low-voltage power supply is less than one kilovolt (kV).

4. The method as claimed in claim 1, wherein the grid fault is a failure of the electrical power supply grid.

5. The method as claimed in claim 1, wherein the grid fault is a persistent failure of the electrical power supply grid.

6. The method as claimed in claim 1, wherein the predefined switching state is preset by the grid operator of the electrical power supply grid.

7. The method as claimed in claim 1, wherein after switching the second electrical switch, the wind power installation or the wind farm has an operating state in which at least one function is executable from a list of functions including: start-up of the wind power installation or the wind farm using auxiliary services; operation of the wind power installation or the wind farm using the auxiliary services; switching the first electrical switch or the second electrical switch, wherein the first electrical switch is a first circuit breaker or a first bus coupler, and wherein the second electrical switch is a second circuit breaker or a second bus coupler; and synchronization of the wind power installation or the wind farm with the electrical power supply grid.

8. The method as claimed in claim 1, wherein the switching of the second electrical switch of the wind power installation or the wind farm to the predefined switching state is performed after notifying the grid operator that the second electrical switch is to be switched.

9. The method as claimed in claim 1, comprising: verifying the grid fault with the grid operator of the electrical power supply grid.

10. The method as claimed in claim 1, comprising: transmitting status information, to the grid operator of the electrical power supply grid, indicating that the second electrical switch of the wind power installation or the wind farm has been switched.

11. The method as claimed in claim 1, comprising: activating a fault-case regulation of the wind power installation or the wind farm in which safe operation of the wind power installation or the wind farm is enabled despite the grid fault.

12. The method as claimed in claim 1, comprising: DC-isolating the wind power installation or the wind farm from the electrical power supply grid using the first electrical switch to deenergize the wind power installation or the wind farm, wherein the first electrical switch is a circuit breaker or a bus coupler.

13. A wind power installation or wind farm, comprising: an electrical storage device; and a controller configured to perform the method as claimed in claim 1.

14. The wind power installation or wind farm as claimed in claim 13, wherein the low-voltage power supply has a DC voltage.

15. The wind power installation or wind farm as claimed in claim 13, wherein the second electrical switch is a circuit breaker or a bus coupler, and wherein the second electrical switch is configured to connect the wind power installation or the wind farm to the electrical power supply grid at the point of common coupling.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The present invention will now be explained in more detail below by way of example using exemplary embodiments with reference to the attached figures, wherein the same reference symbols are used for identical or similar assemblies.

(2) FIG. 1 shows a schematic view of a wind power installation in accordance with one embodiment.

(3) FIG. 2 shows a schematic view of a wind farm in accordance with one embodiment.

(4) FIG. 3 shows a schematic flowchart of a method for controlling a wind farm in accordance with one embodiment.

DETAILED DESCRIPTION

(5) FIG. 1 shows a schematic view of a wind power installation 100 in accordance with one embodiment.

(6) The wind power installation 100 has, for this purpose, a tower 102 and a nacelle 104. An aerodynamic rotor 106 having three rotor blades 108 and a spinner 110 is arranged on the nacelle 104. The rotor 106, during operation, is set in rotary motion by the wind and thereby drives a generator in the nacelle 104.

(7) In addition, the wind power installation 100 has a wind power installation control unit as described above or below which is connected to a wind farm control unit, in particular as described above or below, and/or a grid operator.

(8) FIG. 2 shows a schematic design of a wind farm 1000 in accordance with one embodiment.

(9) The wind farm 1000 comprises a plurality of wind power installations 1100, as shown, by way of example, in FIG. 1, which are connected to one another via a common wind farm grid 1200.

(10) The wind farm grid 1200 has one or more switches (of which switch 1210 is shown in FIG. 2), in particular a bus coupler for the wind farm, and one or more further switches which further switch 1220 is shown in FIG. 2) and is connected to an electrical power supply grid 2000 by means of a wind farm transformer 1300 in order to inject, for example, an electrical wind farm power P.sub.farm which comprises a sum of the individual electrical wind power installation powers P.sub.wpi.

(11) The wind power installation 1100 and the wind farm grid 1200 form, together with the wind farm transformer, the power string (solid lines), i.e., in particular those assemblies which are responsible for the transport of energy into the electrical power supply grid.

(12) In addition, the wind farm 1000 has a wind farm control unit 1400, which is designed to control the wind farm 1000. For this purpose, the wind farm control unit (e.g., wind farm controller) 1400 is in particular connected to the wind power installation control units (e.g., wind power installation controllers) 1180 of the wind power installations 1100.

(13) The wind farm 1000 therefore has, in addition to the power string (solid lines), also a control and control engineering string (dashed lines), which will be described below.

(14) The wind farm control unit 1400 has a plurality of interfaces 1410, 1420, 1430, 1440, 1450, 1460 and a plurality of operating modes B1, B2, B3, such as, for example, a fault-case regulation, and is supplied energy by means of an electrical store (e.g., battery or storage capacitor(s)), in particular even when the wind farm is not generating any electrical power and/or the electrical power supply grid has a grid fault or has failed.

(15) The interface 1410 is designed to transmit signals to a grid operator 3000 or to receive signals from said grid operator. This interface 1410 can also be referred to as grid operator interface.

(16) The interface 1420 is, for example, an interface for the installation operator 4000, which can likewise gain access to the wind farm via this interface 1420. This interface 1420 can also be referred to as wind farm operator interface 1420.

(17) The driving of the individual wind power installations 1100 of the wind farm 1000 takes place via a control interface 1430, which is connected to the individual wind power installation control units 1180, for example by means of various control signals S.sub.NIS.

(18) By means of the interface 1440, the wind farm control unit can disconnect the wind farm from the electrical power supply grid by means of the switch 1210. This interface 1440 can also be referred to as disconnection interface.

(19) By means of the interface 1450, the wind farm control unit can detect the injection (feed-in) by the wind farm and/or a voltage V.sub.grid on the electrical power supply grid 2000. This interface 1450 can also be referred to as measurement interface.

(20) By means of the interface 1460, the wind farm control unit can monitor the state of the electrical store 1500. This interface 1460 can also be referred to as monitoring interface.

(21) By means of the interface 1470, the wind farm control unit can switch a further switch 1220, in particular in such a way that the wind farm has a predefined switching state. This interface can also be referred to as switching interface.

(22) FIG. 3 shows a schematic flowchart 5000 of a method for controlling a wind farm in accordance with one embodiment.

(23) In a first step 5100, a grid fault is established, for example via a measurement interface of a wind farm control unit, as shown in FIG. 2.

(24) In a next step 5200, the grid fault is verified with a grid operator, for example via a grid operator interface, as shown in FIG. 2.

(25) Depending on the grid operator, however, a grid fault can also be assumed once a certain time has elapsed.

(26) In a next step 5300, the wind farm is disconnected from the electrical power supply grid, for example via a disconnection interface by means of a switch, as shown in FIG. 2.

(27) In a next step 5400, the electrical store is tested, for example via a monitoring interface, as shown in FIG. 2, and a further switch switched so that the wind farm has a predefined switching state, in particular in such a way that a grid protection plan of a grid operator is met.

LIST OF REFERENCE SYMBOLS

(28) 100 wind power installation 102 tower, in particular of wind power installation 104 nacelle, in particular of wind power installation 106 aerodynamic rotor, in particular of wind power installation 108 rotor blade, in particular of wind power installation 110 spinner, in particular of wind power installation 1000 wind farm 1100 wind power installation, in particular of wind farm 1200 wind farm grid, in particular of wind farm 1210 switch, in particular bus coupler, in particular of wind farm grid 1220 further switch, in particular of wind farm grid 1300 wind farm transformer, in particular of wind farm 1400 wind farm control unit, in particular of wind farm 1410 grid operator interface, in particular of wind farm control unit 1420 wind farm operator interface, in particular of wind farm control unit 1430 control interface, in particular of wind farm control unit 1440 disconnection interface, in particular of wind farm control unit 1450 measurement interface, in particular of wind farm control unit 1460 monitoring interface, in particular of wind farm control unit 1470 switching interface, in particular of wind farm control unit 1500 electrical store, in particular of wind farm P.sub.farm wind farm power P.sub.wpi wind power installation powers S.sub.NIS control signals, in particular of wind farm control unit V.sub.grid voltage of electrical power supply grid

(29) The various embodiments described above can be combined to provide further embodiments. All of the 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. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.

(30) These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.