Method for controlling an arrangement for supplying electric current to a power supply system

Abstract

The invention relates to a method for controlling a feed arrangement having a wind energy installation for feeding electrical power into an electrical supply system, comprising the following steps: generating electrical power using the wind energy installation from wind, feeding a first proportion of the generated electrical power into the electrical supply system, supplying a second proportion of the generated electrical power to an electrical consumer for consuming the supplied second proportion of the generated electrical power, and wherein, depending on at least one monitored system state and/or depending on the prevailing wind, the second proportion of the generated electrical power which is supplied to the consumer is reduced wholly or partially and the first proportion of the electrical power fed into the electrical supply system is increased correspondingly, and to a corresponding feed arrangement.

Claims

1. A method for controlling a feed arrangement having a wind energy installation for feeding electrical power into an electrical supply system, the method comprising: generating electrical power from wind using the wind energy installation; feeding a first proportion of the generated electrical power into the electrical supply system; supplying a second proportion of the generated electrical power to an electrical consumer configured to consume the supplied second proportion of the generated electrical power; supplying a third proportion of the generated electrical power to an electrical store; monitoring at least one of a system state of the electrical supply system and the wind; and depending on at least one of the monitored system state of the electrical supply system and the wind, reducing an amount of the second proportion of the generated electrical power that is supplied to the consumer and either increasing an amount of the first proportion of the generated electrical power that is fed into the electrical supply system or maintaining the amount of the first proportion of the generated electrical power that is fed into the electrical supply system to stabilize the electrical supply system; and the method comprises at least one of: depending on the at least one monitored system state, drawing electrical power from the electrical store and feeding the drawn electrical power into the electrical supply system; and depending on the at least one monitored system state, reducing the third proportion of the generated electrical power that is supplied to the electrical store and increasing the first proportion of the electrical power.

2. The method according to claim 1, wherein the electrical consumer is a conversion apparatus for converting the generated electrical power into another energy form.

3. The method according to claim 1 wherein, monitoring at least one system state of the electrical supply system comprises at least one of: monitoring a frequency of the electrical supply system; monitoring a voltage of the electrical supply system; evaluating an external signal of the supply system; determining a present demand for electrical power by the supply system; and monitoring a change in frequency of the electrical supply system.

4. The method according to claim 1 wherein: the second proportion of the generated electrical power supplied to the electrical consumer is added to the first proportion of the electrical power fed into the electrical supply system; and the third proportion of the generated electrical power is added to the first proportion of the electrical power fed into the electrical supply system.

5. The method according to claim 1, wherein the feed arrangement includes an inverter with a DC voltage intermediate circuit, and at least one of the first and second proportion of the electrical power is at least partially diverted such that the electrical power is introduced directly into the DC voltage intermediate circuit.

6. A feed arrangement for feeding electrical power into an electrical supply system, the feed arrangement comprising: a wind energy installation for generating electrical power; a feed means for feeding at least one first proportion of the electrical power generated by the wind energy installation; an electrical consumer for consuming at least one second proportion of the electrical power generated by the wind energy installation; and a control device for controlling the feed arrangement, wherein the control device is configured to implement a method according to claim 1.

7. The feed arrangement according to claim 6, wherein the electrical consumer is a conversion apparatus for converting the electrical power into another energy form.

8. The feed arrangement according to claim 6, comprising the electrical store for storing the third proportion of the electrical power generated by the wind energy installation.

9. A wind farm comprising: a plurality of wind energy installations configured to generate electrical power; and a feed arrangement including: an inverter configured to feed a first proportion of the electrical power generated by the plurality of wind energy installations; an electrical consumer for consuming a second proportion of the electrical power generated by the plurality of wind energy installations; an electrical store for storing a third proportion of the electrical power generated by the wind energy installation; and a control device for controlling the feed arrangement, wherein the control device is configured to: reduce a first amount of the second proportion of the generated electrical power that is supplied to the consumer and to increase a second amount of the first proportion of the generated electrical power that is fed into the electrical supply system to stabilize the electrical supply system; and at least one of: depending on at least one monitored system state, draw electrical power from the electrical store and feed the drawn electrical power into the electrical supply system; and depending on the monitored system state, reduce the third proportion of the electrical power and increase the first proportion of the electrical power.

10. The method according to claim 1, wherein the amount of the second proportion of the generated electrical power that is reduced corresponds to the amount of the first proportion of the generated electrical power that is increased.

11. The method according to claim 1, wherein reducing the amount of the second proportion of the generated electrical power that is supplied to the consumer comprises reducing the amount of the second proportion to zero.

12. The method according to claim 2, wherein the other energy form is gas.

13. The method according to claim 4, wherein the second proportion of the generated electrical power supplied to the electrical consumer is added to the first proportion of the electrical power fed into the electrical supply system by diverting the second proportion of the generated electrical power through a switchover operation such that the second portion together with the first proportion is ready to be fed into the electrical supply system.

14. The feed arrangement according to claim 8, wherein the control device is a microcontroller.

15. The feed arrangement according to claim 9, wherein the other energy form is a gas.

16. The feed arrangement according to claim 6, comprising an inverter with a DC voltage intermediate circuit for feeding the first proportion of the electrical power into the electrical supply system.

17. The feed arrangement according to claim 6, wherein the feed arrangement comprises a plurality of wind power installations.

18. The method according to claim 1, wherein the amount of the first proportion of the generated electrical power that is fed into the electrical supply system is increased in response to an increase in power demand by the electrical supply system or the amount of the first proportion of the generated electrical power that is fed into the electrical supply system is maintained in response to a drop in a power supplied by the wind energy installation.

19. A method for controlling a feed arrangement having a wind energy installation for feeding electrical power into an electrical supply system, the method comprising: generating electrical power from wind using the wind energy installation; feeding a first proportion of the generated electrical power into the electrical supply system; supplying a second proportion of the generated electrical power to an electrical consumer configured to consume the supplied second proportion of the generated electrical power; supplying a third proportion of the generated electrical power to an electrical store; monitoring at least one of a system state of the electrical supply system and the wind; and in response to a reduction in the wind, reducing an amount of the second proportion of the generated electrical power that is supplied to the consumer and maintaining an amount of the first proportion of the generated electrical power that is fed into the electrical supply system to maintain stability of the electrical supply system; and the method comprises at least one of: depending on the at least one of the system state of the electrical supply system and the wind, drawing electrical power from the electrical store and feeding the drawn electrical power into the electrical supply system; and depending on the at least one of the system state of the electrical supply system and the wind, reducing the third proportion of the generated electrical power that is supplied to the electrical store and increasing the first proportion of the electrical power.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention will now be explained in more detail below by way of example using exemplary embodiments with reference to the attached figures.

(2) FIG. 1 shows a wind energy installation in a schematic view.

(3) FIG. 2 shows a feed arrangement schematically in a simplified overview.

(4) FIG. 3 shows a graph illustrating power divisions.

DETAILED DESCRIPTION

(5) FIG. 1 shows a wind energy installation 100 with a tower 102 and a pod 104. A rotor 106 with three rotor blades 108 and a spinner 110 is arranged on the pod 104. The rotor 106 is caused to perform a rotary movement during operation owing to the wind and thereby drives a generator in the pod 104.

(6) FIG. 2 shows a feed arrangement 1 with a wind energy installation 2, such as the wind energy installation 100 of FIG. 1, a feed means 4, such as an inverter, an electrical consumer 6, which in one embodiment is a power conversion apparatus 6, an electrical store 8 and a control device 10, which in the illustrated embodiment is a microcontroller 10.

(7) During operation in accordance with one operating mode, in which there is sufficient wind, the wind energy installation 2 generates an electrical AC voltage by virtue of the generator 12, which is driven by the wind via the aerodynamic rotor 14. This generated AC voltage is supplied to a rectifier 16, which generates a DC voltage from the AC voltage, which is then supplied to a distribution unit 18. The distribution unit 18 is in particular understood to be a symbolic illustration of the power distribution described below. In practice, the power distribution which is intended to be illustrated by the distribution unit 18 can also manage without any physical embodiment of such a distribution unit 18.

(8) In any case, FIG. 2 illustrates, with the distribution unit 18, the fact that first all of the electrical power generated by the wind energy installation 2 is supplied to said distribution unit. Any losses which may occur in the rectifier 16, for example, are not taken into consideration here. Therefore, all of the generated electrical power P.sub.0 of the wind energy installation 2 is available at the distribution input 20. All of this electrical power P.sub.0 is now divided into the first proportion or the first power proportion P.sub.1, the second proportion or the second power proportion P.sub.2 and the third proportion or the third power proportion P.sub.3. Correspondingly, the equation P.sub.0=P.sub.1+P.sub.2+P.sub.3 applies. It is first assumed that the first, second and third power proportions P.sub.1, P.sub.2 and P.sub.3 are each not equal to 0 and correspondingly the first, second and third proportion switches S.sub.1, S.sub.2 and S.sub.3 shown symbolically and associated with the respective power proportion are closed.

(9) Therefore, the first power proportion P.sub.1 is supplied to the feed means 4, namely the inverter 4. In addition, the inverter 4 generates a corresponding alternating current for feeding to the electrical supply system 22, which is also referred to in simplified form below as system 22. In the example shown in FIG. 2, in addition a transformer 24 is illustrated which can transform the AC voltage generated by the inverter 4 into a higher voltage value if, for example, the feed is to a medium-voltage system. This transformer 24 is not absolutely essential, but it illustrates that the feed arrangement 1 and therefore the wind energy installation 2 can feed not only into a low-voltage system, which is generally also a small system, but also into a medium-voltage system and therefore a correspondingly large system, for example. In principle, however, feeding into a high-voltage system is also possible, in particular when a wind farm with a high capacity is provided and also depending on the system topology encountered at the installation site.

(10) The second power proportion P.sub.2 is supplied to the conversion apparatus 6, which can thus produce or convert a gas, which can be fed into a gas system or the like. Illustratively, as a representative of this, a gas system or gas pipeline 26 is referred to as GAS-L and a gas store or gas tank 28 is referred to as GAS-T. In principle, a gas store 28 or many gas stores can be part of the gas system 26.

(11) The third power proportion P.sub.3 is supplied to an electrical store 8 in order to charge said electrical store. The electrical store 8 is in this case symbolized as a battery store which can have a plurality of storage banks. However, other stores are also conceivable, such as capacitor banks, for example, which can be provided at least in supplementary fashion. The third power proportion P.sub.3 can also in principle become negative, with energy thus being drawn from the electrical store 8. This is illustrated by the double arrow 30, whereas a single arrow 32 illustrates, both for the first power P.sub.1 and for the second power P.sub.2, that the power in each case only flows to the inverter 4 or to the conversion apparatus 6 although the conversion apparatus 6 can in principle also have a bidirectional embodiment.

(12) The inverter 4 is also preferably embodied as FACTS-compatible and/or can implement functions of a STATCOM. Both abbreviations are known in the field of power supply system technology and have the following meanings: FACTS: flexible AC transmission system STATCOM: static synchronous compensator

(13) Therefore, the inverter 4 is set up not only to feed electrical power into the electrical power supply 22, but also to have a qualitative influence, in particular by influencing the phase angle of the fed power. At this juncture, mention should also be made of the fact that the feed arrangement is based on an electrical supply system which is not an island network. There are particular prerequisites, in particular in terms of frequency specifications and indicators and intervention possibilities in respect of system stability, for island networks.

(14) In order to control the inverter 4, the conversion apparatus 6, the electrical store 8 and the distribution unit 18 or the functionality thereof, the control device 10 is provided. The control device 10 in this case provides a superordinate control which predetermines regulation or control objectives which are superordinate in particular to the inverter 4, the conversion apparatus 6 and the electrical store 8, in particular in respect of power distribution. In particular, the specific value for the first power proportion P.sub.1, the second power proportion P.sub.2 and the third power proportion P.sub.3 can be translated in each case by internal control or regulation of the inverter 4, the conversion apparatus 6 and the electrical store 8. The distribution unit 18 can control the switch position of the three switches S.sub.1, S.sub.2 and S.sub.3, if appropriate.

(15) For this superordinate control, the control device 10 can use one of the control lines 34 or 36. In FIG. 2, the first control line 34 is coupled to the distribution unit 18 and the second control line 36 is coupled to the inverter 4 and, from there, is looped through to the conversion apparatus 6 and to the electrical store 8. The specific topology of the control lines can in principle be as desired and can be implemented in an otherwise known manner using known topologies.

(16) In order to detect at least one system state of the supply system 22, in addition a system data line 38 is provided, via which the control device receives information such as frequency and voltage amplitude of the system voltage of the system 22, for example. Further data can be supplied to the control device 10 via an input data line 40, in particular data from an external unit such as a system operator or a central evaluation unit for evaluating the present consumer demand, for example. Representative of such and further external evaluation units is the block 42, which is denoted by EXT as representative of an external unit.

(17) In principle, the first and second control lines 34, 36, the system data line 38 and the input data line 40 can transmit different signals, and the control device 10 can thus both receive and transmit signals. In this case, the primary information direction of the first and second control lines 34, 36 is from the control device 10 to the respectively connected devices, namely the inverter 4, the conversion apparatus 6, the electrical store 8 and the distribution unit 18. In the case of the system data line 38 and the input data line 40, the information direction is in particular towards the control device 10. However, it is also possible, for example, for information to be supplied from the inverter 4 to the control device 10. This information can represent both specific states of the inverter 4 and, if appropriate, contain system information, i.e., when the inverter 4 itself has corresponding measurement means for system states, which is mentioned here for reasons of completeness.

(18) If the control device 10 now establishes that there is a demand for power diversion, i.e., a change in the division of power between the power proportions P.sub.1, P.sub.2 and P.sub.3, there is first the possibility of giving this information or corresponding control commands to the relevant units, namely in particular the inverter 4, the conversion apparatus 6, the electrical store 8 and the distribution unit 18. Depending on this, the conversion apparatus 6 can reduce its power, with the result that the second power proportion P.sub.2 is reduced, possibly to 0. Correspondingly, the electrical store 8 can reduce its power consumption, namely reduce the decrease in the third power proportion P.sub.3, and possibly reverse this, with the result that the electrical store emits power.

(19) A different or supplementary variant is that the distribution unit 18 opens the second switch S.sub.2 and then immediately reduces the second power proportion P.sub.2 to 0. Likewise, the third switch S.sub.3 can be opened in order to reduce the power which is supplied to the electrical store 8 likewise immediately to 0. In this case, the first switch S.sub.1 is closed.

(20) In order to make available energy from the electrical store 8 for feeding, the third switch S.sub.3 can be closed again. In respect of the electrical store, it should be mentioned that said electrical store in principle does not draw any power or draws little power during permanent operation and during running operation in contrast to the conversion apparatus 6. Finally, the electrical store can draw power until it is charged to its maximum.

(21) The electrical conversion apparatus 6 therefore has a different significance than the electrical store 8 and thus a corresponding treatment is proposed. Accordingly, the operation can in principle be described on the basis of a concept which initially does not take into consideration the electrical store 8. With this consideration, the third switch S.sub.3 would be open and the third power proportion would be P.sub.3=0.

(22) The conversion apparatus 6 preferably operates in the continuous operating mode by virtue of it receiving, for example, approximately 50% of the electrical power generated by the wind energy installation 2 during continuous operation and continuously producing gas or another energy carrier. In this example, the second power proportion P.sub.2 is 50% of the total electrical power P.sub.0 provided. Correspondingly, the first power proportion P.sub.1 is then also 50% of the total power P.sub.0. If, for simplicity's sake, even if this is the rarer case depending on the installation site of the wind energy installation 2, it is assumed that there is nominal wind and therefore rated power, a 2 MW wind energy installation 2 can provide 2 MW of power as P.sub.0, for example, of which one 1 MW is fed into the system 22 as first power proportion P.sub.1 from the inverter 4. At the same time, the conversion apparatus receives 1 MW for producing the gas. From the point of view of the electrical supply system 22, accordingly a 1 MW wind energy installation is provided which feeds into the system.

(23) If the demand for electrical power in the system 22 now increases suddenly or gradually, this 1 MW electrical source can increase its power, namely to 2 MW in the example. In fact, however, no power increase takes place because the wind energy installation continues to produce 2 MW but, from the point of view of the system, a power increase takes place. This power increase can in this case be implemented continuously, whether it be for a few seconds, a few minutes, a few hours, days or weeks, since the conversion apparatus 6 is in this case designed in such a way that it is possible to dispense with the gas production or other production at any point in time or for this gas production or other production to be reduced at any time.

(24) In addition, the inverter 4 can still feed the 1 MW, mentioned by way of example, into the system 22 when the wind speed is reduced. In the example mentioned, the wind speed can decrease to such an extent that the wind energy installation 2 produces only half the rated power, namely 1 MW. In this case, it is still possible for 1 MW of power to be fed from the inverter 4 into the system 22, i.e., when in this case no more power is supplied to the conversion apparatus 6.

(25) In addition, the electrical store 8 can also be used, with this electrical store being suitable in particular for additionally providing electrical power for feeding for a comparatively short period of time, depending on the dimensions of the store capacity.

(26) The described concept can be implemented particularly easily by virtue of the fact that the power distribution, namely the division of the total power P.sub.0 into the first, second and third power proportions P.sub.1, P.sub.2 and P.sub.3, takes place on the DC voltage plane and in particular is added to the inverter 4 directly to its DC voltage intermediate circuit. The change in the first power proportion P.sub.1, which therefore flows directly into the DC voltage intermediate circuit of the inverter 4, is in principle only noticeable owing to the fact that the current flowing into the DC voltage intermediate circuit is increased. The voltage of the DC voltage intermediate circuit can remain substantially the same.

(27) The graph in FIG. 3 represents, for illustrative purposes, power profiles P over time t. In this case, a feed arrangement which comprises a wind energy installation WEA and a consumer, namely a conversion apparatus for producing methane, is assumed, by way of example. An electrical store is not provided for the embodiment under consideration here or is not taken into consideration.

(28) The graph is based on a situation in which the wind energy installation substantially generates a constant power P.sub.WEA. Of this power P.sub.WEA, first a first proportion is fed as P.sub.Net into an electrical supply system and the remaining second proportion P.sub.Meth is supplied to the conversion apparatus. Losses are ignored here. At time t.sub.x, there is suddenly an increased demand for power P.sub.Net to be fed and, for this, the second proportion P.sub.Meth is reduced, namely to zero in the example shown, with the result that this proportion can be added to the fed power P.sub.Net. P.sub.Net increases correspondingly and increases to the value of the generated power P.sub.WEA. Therefore, the fed power P.sub.Net can be increased to this higher value suddenly by the proposed method. This increased power P.sub.Net can also be maintained for a relatively long period of time, as long as there is sufficient wind.

(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.