METHOD FOR PROVIDING A REQUESTED REAL POWER

Abstract

A method for providing a requested real power including receiving the requested real power at a transmission feed-in point; using a real power band with an upper band limit and a lower band limit, each of which is disposed with an offset from the requested real power. The real power band furthermore comprises at least one control threshold value between the upper band limit and the lower band limit. The method includes controlling at least one regenerative energy generator depending on the at least one control threshold value, in particular in order to provide the requested real power as transmission power at the transmission feed-in point.

Claims

1. A method for providing a requested real power as a transmission power at a transmission feed-in point of an electrical supply grid that electrically connects a first voltage segment to a second voltage segment, wherein the second voltage segment includes at least one regenerative energy generator, the method comprising: receiving the requested real power that is requested at the transmission feed-in point; controlling the transmission power at the transmission feed-in point using a real power band, the real power band having: an upper band limit and a lower band limit each being at a respective offset from the requested real power, and at least one control threshold value between the upper band limit and the lower band limit; and controlling the at least one regenerative energy generator depending on the at least one control threshold value to provide the requested real power as the transmission power at the transmission feed-in point.

2. The method as claimed in claim 1, wherein: the first voltage segment of the electrical supply grid has a first nominal voltage, the second voltage segment of the electrical supply grid has a second nominal voltage, and the first nominal voltage is greater than the second nominal voltage, wherein the first nominal voltage is at least 110 kilovolts (kV) and the second nominal voltage is at least 10 kV.

3. The method as claimed in claim 1, wherein a transformer is arranged at the transmission feed-in point, wherein the transformer is configured to electrically connect the first voltage segment and the second voltage segment.

4. The method as claimed in claim 1, comprising: receiving the real power band from a transmission grid operator.

5. The method as claimed in claim 1, comprising: measuring, by a distribution grid operator, the transmission power at the transmission feed-in point; controlling the at least one regenerative energy generator depending on the measured transmission power; and determining a trigger signal for triggering the at least one control threshold value based on the measured transmission power.

6. The method as claimed in claim 1, wherein the respective offsets of the upper band limit and the lower band limit from the requested real power are relative offsets and/or an absolute offsets relative to the requested real power.

7. The method as claimed in claim 1, wherein the respective offsets of the upper band limit and the lower band limit are each associated with a minimum offset in relation to the requested real power, wherein each minimum offset is at least 5 megawatts (MW).

8. The method as claimed in claim 1, wherein the respective offset of the upper band limit is a predefined positive offset from the requested real power in a range of: 3% to 6% of a conventional installed power coupled to the second voltage segment; 40% to 60% of the requested real power; or 60% to 80% of the requested real power.

9. The method as claimed in claim 1, wherein the respective offset of the lower band limit is a predefined negative offset from the requested real power in a range of: 3% to 6% of a conventional installed power coupled to the second voltage segment; 40% to 60% of the requested real power; or 60% to 80% of the requested real power.

10. The method as claimed in claim 1, wherein the real power band has a real power bandwidth that is predefinable, wherein the real power bandwidth is a sum of magnitudes of the respective offsets of the upper band limit and the lower band limit from the requested real power, and wherein the real power bandwidth is at least 10 MW.

11. The method as claimed in claim 1, comprising: changing the real power band during operation by performing at least one change from a list of changes including: an increase or reduction of a real power bandwidth; a change in the respective offset of the upper band limit; a change in the respective offset of the lower band limit; and a shift of the real power band by an offset factor depending on at least one of a list of dependencies including: a reception of an external change signal; a stability parameter of the electrical supply grid, wherein the stability parameter expresses a strength in a reaction of the electrical supply grid to a change of a parameter that has an influence on the first voltage segment or the second voltage segment; a number of regenerative energy generators coupled to the second voltage segment; a total installed power in the first voltage segment and/or in the second voltage segment of the electrical supply grid; a total synchronous inertia in the first voltage segment and/or in the second voltage segment of the electrical supply grid; and a number and size of loads that are to be switched into the second voltage segment.

12. The method as claimed in claim 1, wherein: the at least one control threshold value is an upper threshold value of the requested real power, and the method comprises: triggering an increase in a real power of the at least one regenerative energy generator that is fed in when the requested real power exceeds the upper threshold value.

13. The method as claimed in claim 1, wherein: the at least one control threshold value is a lower threshold value associated with the lower band limit, and the method comprises: triggering a reduction in a real power of the at least one regenerative energy generator that is fed in when the lower band limit decreases below the lower threshold value to counteract an excess of real power in the first voltage segment.

14. The method as claimed in claim 1, wherein: the at least one control threshold value is a threshold value associated with a predefined value between the requested real power and the lower band limit, and the method comprises: causing a real power of the at least one regenerative energy generator to be held constant when the predefined value decreases below the threshold value.

15. The method as claimed in claim 12, comprising: value when the at least one control threshold value is reached, generating a feed signal depending on the at least one control threshold value, and wherein the feed signal is configured for the at least one regenerative energy generator for controlling a real power feed of the at least one regenerative energy generator, and/or when the at least one control threshold value is reached, generating a switch-in signal depending on the at least one control threshold value, and wherein the switch-in signal is configured for the at least one regenerative energy generator, and the at least one regenerative energy generator is switched into the second voltage segment or out of the second voltage segment to control real power generation.

16. The method as claimed in claim 1, comprising: specifying, by a grid operator, the requested real power; specifying, by a transmission grid operator of the first voltage segment, the requested real power as a real power setpoint value; specifying, by the transmission grid operator of the first voltage segment, the requested real power as the real power setpoint value that is constant over time or follows a ramp curve; or specifying, by the transmission grid operator of the first voltage segment, the real power band, the upper band limit, the lower band limit or the at least one control threshold value.

17. The method as claimed in claim 1, comprising: changing the at least one control threshold value during operation by performing at least one change from a list of changes including: an increase or reduction of an upper threshold value; an increase or reduction of a lower threshold value; and an increase or reduction of a constant threshold value; or changing the at least one control threshold value during operation depending on at least one of a list of dependencies including: a reception of an external change signal; a stability parameter of the electrical supply grid, wherein the stability parameter expresses a strength in a reaction of the electrical supply grid to a change of a parameter that has an influence on the first voltage segment or the second voltage segment; a number of regenerative energy generators coupled to the second voltage segment; a total installed power in the first voltage segment and/or in the second voltage segment of the electrical supply grid; a total synchronous inertia in the first voltage segment and/or in the second voltage segment of the electrical supply grid; and a number and size of loads that are to be switched in to the second voltage segment.

18. The method as claimed in claim 1, wherein the controlling the at least one regenerative energy generator depending on the at least one control threshold value includes: specifying a limited real power feed per unit of time for the at least one regenerative energy generator, wherein the specified limited real power feed is defined as:
P.sub.reg=k*P.sub.out/T.sub.int, wherein k is a limiting factor, P.sub.out is an output power of the at least one regenerative energy generator, and T.sub.int is a predetermined time interval.

19. The method as claimed in claim 18, wherein the limiting factor is less than 1 and in a range of one of: 0.2 to 0.4; 0.4 to 0.6; and 0.6 to 0.8.

20. The method as claimed in claim 18, comprising: changing the limiting factor during operation depending on a primary regulation rate of counter-regulating conventional energy generators that are coupled to the second voltage segment; and/or changing the limiting factor during operation depending on a fluctuation following a power run.

21. The method as claimed in claim 18, wherein the predetermined time interval is less than 10 minutes, less than 5 minutes, less than 1 minute or less than 30 seconds.

22. A power regulator that is a secondary power regulator for providing a requested real power as a transmission power at a transmission feed-in point of an electrical supply grid, comprising at least: a receiver configured to receive the requested real power at the transmission feed-in point, the transmission feed-in point electrically connects a first voltage segment to a second voltage segment, the second voltage segment including at least one regenerative energy generator; and a controller configured to: operate using a real power band having an upper band limit and a lower band limit each being at a respective offset from the requested real power, the real power band having at least one control threshold value between the upper band limit and the lower band limit; and output a control signal to control the at least one regenerative energy generator depending on the at least one control threshold value to cause the requested real power to be provided as the transmission power at the transmission feed-in point.

23. A windfarm for providing a requested real power at a transmission feed-in point of an electrical supply grid that electrically connects a first voltage segment to a second voltage segment, comprising: a farm control controller configured to receive a control signal from a higher-level power regulator and determine an installation control signal; a plurality of wind power installations that are each configured to receive the installation control signal and generate an installation power depending on the installation control signal; and at least one installation transformer configured to transfer the generated installation power into an electrical farm grid, wherein the electrical farm grid is connected to the second voltage segment via a farm transformer, and the electrical farm grid is configured to feed the installation power of the plurality of wind power installations as windfarm power into the second voltage segment.

24. A wind power installation for providing a requested real power at a transmission feed-in point, of an electrical supply grid, that electrically connects a first voltage segment to a second voltage segment, comprising: an installation controller configured to receive a control signal from a higher-level controller; and a feed device configured to feed an installation power into a farm grid depending on the received control signal.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0170] The present invention will now be explained in more detail below by way of example with reference to exemplary embodiments in the light of the accompanying figures, wherein the same reference signs are used for identical or similar assemblies:

[0171] FIG. 1 shows schematically a perspective view of a wind power installation in one form of embodiment.

[0172] FIG. 2 shows schematically a structure of a regenerative power generator in one form of embodiment.

[0173] FIG. 3 shows schematically a structure of an electrical supply grid in which a requested real power P.sub.req is made available with a real power band.

[0174] FIG. 3A shows schematically a band control principle with a real power band in one form of embodiment.

[0175] FIG. 4 shows schematically a process flow of the method in one form of embodiment.

[0176] FIG. 5A shows schematically a structure of an electrical supply grid with a band control principle in a further form of embodiment.

[0177] FIG. 5B shows schematically a real power band in a further form of embodiment.

[0178] FIG. 6A shows schematically a control principle with a real power band in a further form of embodiment.

[0179] FIG. 6B shows schematically a control principle with a real power band in a further form of embodiment.

[0180] FIG. 6C shows schematically a control principle with a real power band in a further form of embodiment.

[0181] FIG. 7 shows schematically a control principle with a real power band in a further form of presentation.

DETAILED DESCRIPTION

[0182] FIG. 1 shows a perspective view of a wind power installation 100 for the provision of a requested real power in one form of embodiment which, for example, is part of a windfarm, as for example shown in FIG. 2.

[0183] The wind power installation 100 comprises for this purpose a tower 102 and a nacelle 104. An aerodynamic rotor 106 with three rotor blades 108 and a spinner 110 is arranged at the nacelle 104. The rotor 106 when operating is set into rotary movement by the wind, thereby driving a generator in the nacelle 104. The generator hereby generates a current which, by means of a full converter that operates in a current-forming manner, is supplied to a wind power installation transformer that is connected to a windfarm grid.

[0184] The wind power installation 100 furthermore comprises an installation control unit 112 (installation controller) that is configured to receive an installation control signal S.sub.WT from a higher-level controller 114, preferably from a farm control unit FCU.

[0185] The installation control unit 112 is, for example, designed as a “control unit” CU, and controls the wind power installation 100, preferably depending on the received installation control signal S.sub.WT.

[0186] The installation control unit 112 is, particularly preferably, configured to carry out and/or to participate in a method for the provision of a requested real power as described above or below.

[0187] The wind power installation 100 further comprises a feed device for feeding a wind power installation power P.sub.WT preferably to a full converter as described above or below.

[0188] The feed device is furthermore configured to feed the wind power installation power P.sub.WT into a farm grid, preferably depending on the received installation control signal S.sub.WT.

[0189] FIG. 2 shows in one form of embodiment a schematic structure of a regenerative energy generator, namely a windfarm 1000, for the provision of a requested real power. The regenerative energy generator 1000 is, for example, part of an electrical supply grid 2000, as shown for example in FIG. 3.

[0190] The windfarm 1000 feeds a windfarm power P.sub.reg at a grid connection point PCC into the electrical supply grid 2000, and is preferably controlled by a power regulator 3000, as shown for example in FIG. 3.

[0191] For generating the windfarm power P.sub.reg, the windfarm 1000 comprises a plurality of wind power installations 1100, in particular four wind power installations, preferably as shown in FIG. 1.

[0192] The wind power installations 1100 generate a wind power installation power P.sub.WT, each of which is fed via an installation transformer 1150 into an electrical farm grid 1200, and added there to the windfarm power P.sub.reg.

[0193] The farm grid 1200 itself connects the installation transformers 1150 together electrically, and is also connected at the grid connection point PCC to the electrical supply grid 2000 by means of a connecting line 1300 comprising a windfarm transformer 1250.

[0194] The windfarm 1000 furthermore comprises a farm control unit (FCU) 1350 provided for control of the windfarm power P.sub.reg. The farm control unit 1350 is thus configured to control the individual wind power installations 1100 of the windfarm 1000.

[0195] The farm control unit 1350 for example controls the wind power installation power P.sub.WT of the wind power installations 1100 depending on the received control signal S.sub.reg of the power regulator 3000.

[0196] The farm control unit 1350 further preferably also controls the wind power installation power P.sub.WT of the wind power installations 1100 through the specification of an installation control signal S.sub.WT that is specified in each case to an installation control unit CU of the wind power installations 1100.

[0197] The farm control unit 1350 is further preferably configured to carry out a method as above or below for the provision of a requested real power with a real power band, or to participate in such a method.

[0198] FIG. 3 shows schematically a structure of an electrical supply grid 2000 with at least one regenerative energy generator 1000 that is controlled by a power regulator 3000.

[0199] The electrical supply grid 2000 here comprises a first voltage segment 2100 and a second voltage segment 2200.

[0200] The first voltage segment 2100 and the second voltage segment 2200 are connected together electrically for the exchange of power at a transmission feed-in point HVP by means of a transmission transformer 2400 and a transmission line 2300.

[0201] The transmission transformer 2400 is here configured for the transmission of a transmission power P.sub.trans between the first voltage segment 2100 and the second voltage segment 2200, and preferably transmits the transmission power P.sub.trans from the second voltage segment 2200 into the first voltage segment 2100 and vice versa.

[0202] To generate the transmission power P.sub.trans, the electrical supply grid 2000 comprises at least one controllable regenerative energy generator 1000, for example a windfarm as is shown in FIG. 2, along with further grid participants, for example further generators 4100 such as conventional power stations, and consumers 4200, such as for example households or blast furnaces.

[0203] The generators 4100 are electrically connected here for the feed of a power P.sub.conv to the second voltage segment 2200, and are preferably designed as conventional power stations.

[0204] The consumers 4200 are electrically connected to the second voltage segment 2200 to draw a power P.sub.load, and can, for example, be referred to as grid load.

[0205] The controllable, regenerative energy generator 1000 is further connected electrically at a grid connection point PCC to the second voltage segment 2200 for feeding in an electrical power P.sub.reg.

[0206] The regenerative energy generator 1000 is preferably a windfarm WP, such as is shown for example in FIG. 2.

[0207] To control the regenerative energy generator 1000, the electrical supply grid 2000 comprises a power regulator 3000 that is configured to control the regenerative energy generator 1000 with a control signal S.sub.reg, as described above or below.

[0208] The power regulator 3000 comprises a receiving device 3100 (receiver) and a band control unit 3200 (controller) for this purpose.

[0209] The receiving device 3100 is configured for receiving the requested real power P.sub.req that is to be set as the transmitted power P.sub.trans at the transmission feed-in point. The requested real power P.sub.req for the transmission feed-in point is for example received for this purpose via a grid control system from a grid operator as the real power setpoint value P.sub.req.

[0210] The receiving device 3100 is preferably also configured for receiving an acquired transmission power P.sub.trans at the transmission feed-in point, which is for example measured at the transmission feed-in point or calculated for the transmission feed-in point.

[0211] The band control unit 3200 is furthermore configured for the generation of a control signal S.sub.reg that is specified to the regenerative energy generator 1000.

[0212] To generate the control signal S.sub.reg, the band control unit 3200 uses a real power band P.sub.band, as described above or below.

[0213] The real power band P.sub.band is implemented for this purpose depending on the requested real power P.sub.req in the band control unit 3200, for example a control program.

[0214] The regenerative energy generator 1000 thus changes the power P.sub.reg that it feeds in depending on the control signal S.sub.reg.

[0215] The power regulator 3000 thus controls the power P.sub.reg of the regenerative energy generator 1000 fed into the second voltage segment 2200 with a real power band P.sub.band that is implemented in the power regulator 3000.

[0216] The power P.sub.reg that is fed in here is preferably a real power.

[0217] The power regulator 3000 is in addition particularly preferably configured to carry out a method as above or below for the provision of a requested real power.

[0218] The control principle of the real power band P.sub.band is described in the supplementary FIG. 3A.

[0219] FIG. 3A shows schematically the control principle with a real power band P.sub.band in a supplementary form of embodiment that is, for example, implemented in the band control unit 3200 of the power regulator 3000, as shown in FIG. 3.

[0220] The real power band P.sub.Band here comprises an upper band limit UL and a lower band limit LL.

[0221] The upper band limit UL and the lower band limit LL are here each disposed at an offset ΔUL, ΔLL from the requested real power P.sub.req.

[0222] The requested real power P.sub.req=5 MW and ΔUL is for example disposed as a positive, absolute offset with ΔUL=2.5 MW above P.sub.req, and ΔLL is disposed as a negative, relative offset with ΔUL=−50%.Math.P.sub.req=−2.5 MW below P.sub.req. In this example, the upper band limit UL and the lower band limit LL are accordingly specified as UL=7.5 MW and LL=2.5 MW.

[0223] The real power band P.sub.Band further comprises at least one control threshold value T1 between the upper band limit UL and the lower band limit LL of the requested real power P.sub.req.

[0224] The control threshold value T1 triggers an increase in the real power P.sub.reg fed in of the at least one regenerative energy generator 1000 when the threshold value T1 is reached positively. The control threshold value T1 can also be referred to as a rise threshold value.

[0225] To control the regenerative energy generator 1000, the transmission power P.sub.trans is acquired, for example at the transmission feed-in point, and made available to the band control unit 3200.

[0226] The transmission power P.sub.trans provided can then be received by the band control unit 3200 and used as a trigger signal in order to trigger the rise threshold value T1.

[0227] The acquired transmission power P.sub.trans is illustrated in segments as a continuous signal in a Cartesian coordinate system in FIG. 3A, in which the real power P is plotted in megawatts on the y-axis and the time t in seconds on the x-axis.

[0228] Up until the time t<t(T1.sup.+) the transmission power P.sub.trans at the band control unit does not reach the rise threshold value T1.

[0229] At time t=t(T1.sup.+) the transmission power P.sub.trans reaches the rise threshold value T1 as a result of a real power increase at the HVP, whereupon the band control unit 3200 generates the control signal S.sub.reg(T1).

[0230] The increase in the transmission power P.sub.trans at the time t(T1.sup.+) can, for example be traced back to the connection of a generator or distribution grid segment to the second voltage segment in a grid establishment situation.

[0231] The control signal S.sub.reg(T1) is thus generated, depending on the rise threshold value T1, for the control of at least one regenerative energy generator 1000, as is shown in FIGS. 2 and 3.

[0232] The real power P.sub.Band, which depends on the requested real power P.sub.req, is thus used to control the at least one regenerative energy generator 1000 depending on the rise threshold value T1 with a control signal S.sub.reg, preferably in a grid establishment situation.

[0233] FIG. 4 shows schematically a process flow of the method for the provision of a requested real power P.sub.req at a transmission feed-in point (HVP) in one form of embodiment.

[0234] The requested real power P.sub.req is provided at a transmission feed-in point of an electrical supply grid that connects a first voltage segment electrically to a second voltage segment. The second voltage segment here comprises at least one regenerative energy generator, for example a windfarm as shown in FIG. 2.

[0235] In a first step S1 the requested real power for the transmission feed-in point is received, for example as a setpoint value signal from a transmission grid operator. The requested real power is, for example, received from a power regulator that is arranged in the second voltage segment.

[0236] Following this, a real power band with an upper band limit and a lower band limit is used or implemented in a second step S2. The real power band can, for example, be implemented in a power regulator, as shown for example in FIG. 3, with defined band limits, band offsets and a control threshold value T1 as a control program in a band control unit.

[0237] The band limits of the real power band are here each disposed with an offset from the requested real power, wherein the real power band comprises at least one control threshold value between the upper band limit and the lower band limit.

[0238] In a next step S3 at least one regenerative energy generator, for example a windfarm as shown in FIG. 2 or 3, is controlled, depending on the at least one control threshold value, in order to provide the requested real power as transmission power at the transmission feed-in point HVP.

[0239] FIG. 5A shows schematically a structure of an electrical supply grid 2000, similar to that shown in FIG. 3, with a power regulator 3000 that uses a real power band, in particular in a further, preferred form of embodiment.

[0240] The first voltage segment 2100 and the second voltage segment 2200 are here arranged vertically, namely as a transmission grid segment and a distribution grid segment.

[0241] The transmission grid segment 2100 here comprises a 380 kV very high-voltage level 2110, and is operated by a transmission grid operator TGO.

[0242] The distribution grid segment 2200 here comprises a 110 kV high-voltage level 2210, and a 20 kV medium-voltage level 2220, and is operated by a distribution grid operator (DGO).

[0243] The transmission grid segment 2100 and the distribution grid segment 2200 are connected together electrically for exchange of the transmission power P.sub.trans via a high-voltage transformer 2400 and a transmission line 2300. The transmission power P.sub.trans can thus be transferred from the distribution grid segment 2200 into the transmission grid segment 2100 or, conversely, from the transmission grid segment 2100 into the distribution grid segment 2200.

[0244] The 110 kV high-voltage level 2210 and a 20 kV medium voltage level 2220 of the distribution grid segment are connected together electrically via a medium-voltage transformer MVT.

[0245] The distribution grid segment 2200 further comprises electrical consumers and generators, namely a conventional power station 4100 that is connected to the 110 kV voltage level 2210 and grid loads 4200 that are connected to the 20 kV voltage level 2220.

[0246] To generate the transmission power P.sub.trans, the distribution grid segment 2200 comprises a plurality of regenerative energy generators 1000, for example a windfarm 1100, a solar power farm 1200, and a plurality of uncontrolled, regenerative small generators 1300.

[0247] The transmission power P.sub.trans is thus generated in the distribution grid segment 2200.

[0248] The supply grid 2000 further comprises a secondary power regulator 3000 for control of the regenerative energy generators 1100, 1200 and 1300 with a control signal S.sub.reg.

[0249] The secondary power generator is configured here to control the windfarm 1100 and the solar power farm 1200 with a feed signal. The windfarm 1100 and the solar power farm 1200 can thus be identified as controllable regenerative energy generators.

[0250] The secondary power generator 3000 is, moreover, configured to control the switching in or switching out of the uncontrolled regenerative small generators 1300 with a switch-in signal.

[0251] The distribution grid segment 2200 comprises switching means K1, K2, K3 for this purpose, which are configured to be controlled by the switch-in signal. Uncontrolled regenerative energy generators are electrically coupled to the switching means, and can be switched in to the 20 kV voltage level 2220 for an increase in the real power or shed for a reduction in the real power. The uncontrolled regenerative energy generators 1300 can thus be referred to as switchable energy generators.

[0252] For control of the regenerative energy generators 1100, 1200 and 1300, the secondary power regulator 3000 receives a requested real power P.sub.req as well as a predefined real power band P.sub.Band from the transmission grid operator TGO, which specifies the band limits UL and LL as well as three control threshold values T1, T2 and T3.

[0253] The control threshold value T1 is designed as a rise threshold value, the control threshold value T2 is designed as a fall threshold value and the control threshold value T3 is designed as a constant threshold value. The requested real power P.sub.req is received via a grid control system as the real power setpoint value together with the predefined real power band P.sub.band.

[0254] The secondary power regulator 3000 also receives a transmission power P.sub.trans at the HVP that is measured by a distribution grid operator VNB.

[0255] The secondary power regulator 3000 then generates the control signals S.sub.reg(T1), S.sub.reg(T2), or S.sub.reg(T3) for control of the regenerative energy generators 1100, 1200 and 1300, depending on the control threshold values T1, T2 and T3 that initiate the corresponding control signal depending on the acquired transmission power. For this purpose it is preferred that each control signal S.sub.reg(T1), S.sub.reg(T2), or S.sub.reg(T3) is assigned to one control threshold value T1, T2 or T3, and is stored as the control program in the function block 3300 in the band control unit.

[0256] FIG. 5B shows schematically a real power band P.sub.Band in a further form of embodiment, and provides a supplementary explanation of the control threshold values T1, T2 and T3 that are shown in FIG. 5A.

[0257] The real power band P.sub.Band has, in particular in comparison with the real power band P.sub.Band that is shown in FIG. 3A, a minimum offset ΔUL,.sub.min and ΔLL,.sub.min in relation to the requested real power P.sub.req. The minimum offset is, for example, +/−2 MW, and is shown dotted.

[0258] The real power band P.sub.Band furthermore comprises an upper band limit UL and a lower band limit LL, each of which can be changed during ongoing operation. This is illustrated by the double arrows at the band limits.

[0259] The real power band P.sub.Band further comprises three control threshold values T1, T2 and T3.

[0260] The first control threshold value T1 is a rise threshold value that corresponds to the requested real power P.sub.req, for example 10 MW.

[0261] The second control threshold value T2 is a fall threshold value that corresponds to the lower band limit LL, 5 MW for example.

[0262] The third threshold value T3 is a constant threshold value that corresponds to a predetermined value between the requested real power P.sub.req and the lower band limit LL, 7.5 MW for example.

[0263] The control threshold values T1, T2 and T3 of the real power band P.sub.Band are here changeable during ongoing operation. This is illustrated by the double arrows at the threshold values.

[0264] The real power band P.sub.Band further comprises a specifiable real power bandwidth AB whose magnitude is the sum of the magnitudes of the offsets (ΔB=|ΔUL|+|ΔLL|) of the upper band limit and the lower band limit, and is, for example, 20 MW.

[0265] FIG. 6A shows schematically the control principle with a real power band P.sub.Band in a further form of embodiment, in particular as the control principle is implemented in the power regulator 3000 in FIG. 5A, particularly preferred as at section A1.

[0266] In particular it is shown how the feed or the generated power P.sub.reg of the at least one regenerative energy generator changes depending on the control threshold values T1, T2 and T3.

[0267] The power regulator 3000 illustrated first receives the real power band P.sub.Band together with the requested real power P.sub.req, for example from a transmission grid operator, as shown in FIG. 5A.

[0268] The real power band P.sub.Band here comprises an upper band limit UL and a lower band limit LL, as well as three control threshold values T1, T2 and T3, in particular as shown in FIG. 5B.

[0269] The control threshold value T1 triggers an increase in the power P.sub.reg fed in of the at least one regenerative energy generator when this is reached positively. T1 is thus triggered by a positive switching edge of the acquired transmission power P.sub.trans. The threshold value T1 is thus a rise threshold value, and triggers the control signal S.sub.reg(T1).

[0270] The control threshold value T2 triggers a reduction in the power P.sub.reg fed in of the at least one regenerative energy generator when this is reached negatively. T2 is thus triggered by a negative switching edge of the acquired transmission power P.sub.trans. The threshold value T2 is thus a fall threshold value, and triggers the control signal S.sub.reg(T2).

[0271] The control threshold value T3 causes the power P.sub.reg fed in of the at least one regenerative energy generator to be held constant when this is reached negatively. T3 is thus triggered by a negative switching edge of the acquired transmission power P.sub.trans. The threshold value T3 is thus a constant threshold value, and triggers the control signal S.sub.reg(T3).

[0272] The power regulator 3000 also receives an acquired transmission power P.sub.trans that is in particular acquired by a distribution grid operator, as shown for example in FIG. 5A.

[0273] The acquired transmission power P.sub.trans is illustrated here in segments as a continuous signal in a Cartesian coordinate system, in which the real power P is plotted in megawatts on the y-axis and the time t in seconds on the x-axis.

[0274] The acquired transmission power P.sub.trans initiates the control threshold values T1, T2 and T3 as trigger signals.

[0275] The switching points of the acquired power P.sub.trans with a control threshold value T1, T2 or T3, are illustrated as circles. The switching points each trigger a control signal S.sub.reg(T1; T2; T3). The intersections of the acquired power P.sub.trans with a threshold value T1, T2 or T3, are also illustrated as triangles. The intersections do not trigger a change in the feed. The control threshold values T1, T2 and T3 are thus triggered depending on the direction of the acquired transmission power P.sub.trans.

[0276] The change to the real power feed P.sub.reg of the regenerative energy generator depending on the three threshold values T1, T2 and T3 is here illustrated as an exemplary graphical curve underneath the real power band P.sub.Band.

[0277] At time t.sub.1, the acquired transmission power P.sub.trans jumps as a result of a load being switched in, for example by a load being switched in at the distribution grid segment 2200 as shown, for example, in FIG. 5A.

[0278] The transmission power P.sub.trans then triggers the rise threshold value T1 with a positive switching edge at the point T1.sup.+. The control signal S.sub.reg(T1) is accordingly generated by the power regulator 3000 and specified to the at least one regenerative energy generator as a control signal S.sub.reg(T1).

[0279] At the time t.sub.1, the at least one regenerative energy generator thereupon starts to increase its fed power P.sub.reg in the form of a ramp. This is illustrated by an upward-pointing arrow in the graphical curve of the real power feed P.sub.reg.

[0280] An increase in the fed power P.sub.reg of the at least one regenerative energy generator thus has the effect that the transmission power P.sub.trans falls at the transmission feed-in point. In particular, as a result of the increased power fed in P.sub.reg of the at least one regenerative energy generator, more real power is generated in the distribution grid segment, and thus less transmission power P.sub.trans is exchanged at the transmission feed-in point.

[0281] The power P.sub.reg fed in does not change at time t.sub.2, since the rise threshold value T1 is reached negatively rather than positively. The increase is accordingly still retained.

[0282] The feed P.sub.reg also does not change at time t.sub.3, since an increase was already triggered at time t.sub.1. The jump in the transmission power P.sub.trans at time t.sub.3 can, for example, be traced back to a further load being switched in at the distribution grid segment.

[0283] The feed is retained at time t.sub.4 analogously to time t.sub.2.

[0284] At time t.sub.5, the threshold value T3 is reached negatively, which causes the real power feed P.sub.reg of the at least one regenerative energy generator to be held constant with a control signal S.sub.reg(T3). This is illustrated by an arrow pointing to the right in the graphical curve of the real power feed P.sub.reg.

[0285] Holding the fed power P.sub.reg of the at least one regenerative energy generator constant thus has the effect that the transmission power P.sub.trans at the transmission feed-in point remains constant.

[0286] A load is switched in again at time t.sub.6.

[0287] The following intersection P1 at time t.sub.9 and the switching point T3 at time to operate analogously to the times t.sub.2 and t.sub.4 or t.sub.5.

[0288] FIG. 6A further illustrates that the real power feed P.sub.reg of the at least one regenerative energy generator is retained until another control threshold is triggered.

[0289] FIG. 6B shows a further form of embodiment of the control principle, with a real power band P.sub.Band, and expands in particular on FIG. 6A.

[0290] At time t.sub.12, or following time t.sub.12, the requested real power P.sub.req is specified by the grid operator, for example by the transmission grid operator of the transmission grid 2100, as a real power setpoint value increasing as a ramp over time, as shown in FIG. 5A.

[0291] The real power band P.sub.Band thus follows the requested real power P.sub.req, since the band limits UL and LL, as well as the control threshold values, are specified in relation to the requested real power P.sub.req.

[0292] At times t.sub.12, t.sub.14, t.sub.16 and t.sub.18 an increase, or a holding constant, of the real power P.sub.reg fed in from the at least one regenerative energy generator is triggered, in particular as described previously in relation to FIG. 6A.

[0293] At time t.sub.15, the control threshold value T2 is reached negatively, which initiates a reduction of the real power feed P.sub.reg of the at least one regenerative energy generator with a control signal S.sub.reg(T2). This is illustrated by a downward-pointing arrow in the graphical curve of the real power feed P.sub.reg.

[0294] A reduction in the fed power P.sub.reg of the at least one regenerative energy generator thus has the effect that the transmission power P.sub.trans rises at the transmission feed-in point. In particular, as a result of the reduced power fed in P.sub.reg of the at least one regenerative energy generator, less real power is generated in the distribution grid segment, and thus more transmission power P.sub.trans is exchanged or drawn from the transmission grid at the transmission feed-in point.

[0295] FIG. 6C shows the band control principle with a real power band P.sub.Band in a further form of embodiment in which the real power feed P.sub.reg is limited, and expands in particular on FIG. 6A.

[0296] To this end, FIG. 6C enlarges the section A1 of FIG. 6A.

[0297] At time t.sub.1, the control threshold value T1 is reached positively, which initiates an increase in the real power feed P.sub.reg of the at least one regenerative energy generator with a control signal S.sub.reg(T3), in particular as described before in relation to FIG. 6A.

[0298] A limited real power feed P.sub.reg per unit of time is defined here for the at least one regenerative energy generator, wherein the specified real power feed P.sub.reg is defined as:

P.sub.reg=k*P.sub.out/T.sub.int.

[0299] Here k is a limiting factor, P.sub.out is an output power of the at least one regenerative energy generator, and T.sub.int is a predetermined time interval.

[0300] As can be seen from the curve of the graph underneath the real power band P.sub.Band, the real power feed P.sub.reg is limited by a limiting factor of k=0.5 for T.sub.int=300 s, that is to P.sub.reg=0.5 MW.

[0301] It is thus in particular proposed that the regenerative energy generator is limited, although it is designed to feed a higher output power P.sub.out of, for example, P.sub.out=1 MW.

[0302] FIG. 7 shows schematically a control principle with a real power band in a further form of presentation 10000.

[0303] The form of presentation 10000 shows the curve of the powers, in particular of the regenerative feed 10100 controlled by means of the method described above or below, the supplied load in the distribution grid 10200, and the exchange power 10300 against time.

[0304] The illustrated case relates in particular to lessening the load of the transmission grid, i.e., a removal of load from the power stations at the transmission grid, or the addition of load to another distribution grid. The intention here is the transfer of power from one distribution grid to another distribution grid.

[0305] The real power band P.sub.Band described above or below is placed around the exchange power 10300.

[0306] The method is performed here as described above or below.

[0307] The total of the controlled regenerative feed 10100 and the exchange power 1300 here corresponds to the power of the supplied load 10200.

[0308] A distribution grid is switched in at time t25.

[0309] The exchange band P.sub.Band is activated at time t26.

[0310] The regenerative feed is subsequently increasingly raised, starting at time t27.

[0311] Switching in loads, for example at times t27, t28, t29, initially has the effect that more power is required at the time. This power is first made available through the exchange power 10300, and replaced over time by regenerative power 10100.

[0312] At time t30 the distribution grid is then able to supply itself entirely regeneratively, and can, for example, provide further power as exchange power to other distribution grids (illustrated by the exchange power in the negative quadrants).

[0313] The band control principle can thus be advantageously employed in order to control windfarms and groupings of windfarms in a voltage segment or grid region.

[0314] It is in addition possible to control the windfarms and groupings of windfarms in combination with other controllable generators, loads and storage systems.

[0315] A few advantages are obtained in this way, which are summarized below as key points: [0316] simplification of the operational control of grids in critical situations and where there is a high number of regenerative energy generators in the voltage segment; [0317] in comparison with manual grid operation in critical grid situations, the combination of an automatic feed control of the regenerative energy generators with a feed signal, and an automatic or manual switching in of loads of uncontrolled energy generators or grid loads with a switch-in signal, enables the fast (partially) automatic restoration of supply; [0318] a load tracking mode of operation can, by conveying a relative setpoint value deviation (modification of P.sub.req to P.sub.trans), be used in other critical grid situations; and [0319] the band control principle can also be used to increase the load on power stations or reduce the load of renewable energy generators in order to ensure the technical minimum load of large power stations.

[0320] The various embodiments described above can be combined to provide further embodiments. 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.