Method for feeding in electric power by means of wind farms

Abstract

The invention relates to a method for feeding electric power into a power supply network at a grid connection point (118) by means of a wind farm (112) having a plurality of wind power installations (100), wherein the wind power installations (100) are connected to the grid connection point (118) via a transmission mechanism; a wind farm regulator is provided for transmitting an active power preset and a reactive power preset to the wind power installations (100); a first power range (401) is preset at each of the wind power installations (100), the first power range covering a range of values ​​for the active power and reactive power to be fed in and being distinguishable between the wind power installations (100), wherein the first power range (401) has an active power limit (411) to be observed by the wind power installations (100) and a reactive power limit that can be reached by the wind power installations; a second power range (412) is preset at the grid connection point (118). 02), the second power range covers a value range for active power and reactive power to be fed in, wherein the second power range (402) has: an active power limit (411) to be observed by the wind farm at the grid connection point (118) and a reactive power limit that can be reached by the wind farm at the grid connection point (118); at least one, a plurality of or all of the wind power devices (100) respectively generate active power and reactive power and transmit the active power and reactive power to the grid connection point (118) taking into account the presetting of the wind farm regulator; the at least one, a plurality of or all of the wind power devices respectively exceed the active power limit (411) of the first power range (401) to be observed by them; wherein the active power limit (411) to be observed is respectively exceeded so that the second power range (402) is observed by the wind farm at the grid connection point (118).

Description

Technical Field

[0001] The invention relates to a method for feeding electrical power into a power supply grid by means of a wind park and also to a wind park which can implement such a method. Background Art

[0002] A wind energy device is known which generates electrical power from the wind and feeds it into a power supply network. Typically, a plurality of wind energy devices which are fed into the power supply network via a common grid connection point are combined into a wind farm. This common grid connection point can in particular have a so-called grid transformer which is fed into the power supply network via it, even though it is not necessarily required. The grid connection point can also be referred to as a feed-in point. In any case, this grid connection point is designed for a feed-in power which is not allowed to be exceeded. Exceeding this usually causes a fuse to be triggered, in particular the feed-in is interrupted in this case by a grid disconnect switch. The maximum feed-in power is usually agreed upon with the grid operator by contract.

[0003] In order to ensure compliance with the planned feed-in power, the wind energy installations are dimensioned or set accordingly to the power limit at the grid connection point, or the power limit at the grid connection point is coordinated with the total power of the wind energy installations in the wind farm, as planned for the wind farm. In the simplest and most intuitive case, this can mean that the wind energy installations in the wind farm are designed so that if the rated wind speed is present, all the wind energy installations together generate as much power as can and is permitted to be fed in at the grid connection point.

[0004] The corresponding operating settings for each wind power installation generally take into account not only the active power that can be generated, but also, in addition, the reactive power exchange that may be required by the grid operator can also be ensured. Each wind power installation is therefore designed to feed in a predetermined active power under corresponding wind conditions and can simultaneously feed in a predetermined reactive power. Reactive power can be fed in or absorbed, which corresponds to the behavior of an overexcited or underexcited synchronous generator. In the following, for simplicity, the term "reactive power feed-in" is used, which includes feed-in and absorption.

[0005] However, if the potentially available reactive power is not called up at the operating point, the wind turbines can still increase their feed-in active power even at rated wind speed, but this can prevent compliance with the active power limits of the grid connection point. At least as long as the potentially available reactive power is not called up, the relevant wind turbines will not be used optimally.

[0006] Remedial measures can be provided by increasing the power limit of the grid connection point, but such measures can be very expensive and sometimes impossible if the power limit of the grid connection point is limited by the characteristics of the power supply network in the area of ​​the grid connection point.

[0007] The German Patent and Trademark Office has searched the following prior arts in the priority applications for the present application: US2014 / 0248123A1; DE 10 2005 032 693A1; US2016 / 0308369A1 and US2011 / 0133461A1. Summary of the invention

[0008] The object of the present invention is therefore to solve at least one of the above-mentioned problems. In particular, a solution is to be proposed in which the grid connection point is used as efficiently as possible when feeding in electrical power. At least an alternative solution to the solutions known to date is to be proposed.

[0009] According to the invention, a method for feeding electrical power into a power supply network is proposed as described below. This method therefore involves feeding electrical power into a power supply network. The feeding takes place at a grid connection point by means of a wind farm. Such a wind farm has a plurality of wind turbines and thus the plurality of wind turbines feed their power into the power supply network as specified at one of the grid connection points.

[0010] To implement the method, the wind power installation is connected to the grid connection point via a transmission mechanism. Such a transmission mechanism is in particular a transmission line (overhead line or underground cable). However, transformers are also particularly suitable, via which the voltage level can be changed.

[0011] In addition, a field regulator is provided for regulating the active power preset and the reactive power preset at the grid connection point, and the field regulator transmits the active power preset and the reactive power preset derived therefrom to the wind energy device. Such a field regulator is therefore provided for implementing regulation for the wind farm. In particular, the field regulator can be used for regulating power management. For this purpose, the field regulator has, in particular, a measuring device at the grid connection point, an algorithm for analysis and calculation, and the possibility of sending the active power preset and the reactive power preset to one, more than one or all wind energy devices in the wind farm. The active power preset and the reactive power preset can be transmitted to each wind energy device individually as a specific power value, for example, or, as another example, as a percentage value.

[0012] It is also proposed that a first power range is respectively predefined at each of the wind turbines, which covers a range of values ​​for active power and reactive power to be fed in and can be differentiated between wind turbines. The first power range is in particular predefined by two limits. The first power range has an active power limit to be observed by the wind turbines and a reactive power limit that can be reached by the wind turbines.

[0013] The active power limit to be observed is therefore a limit which numerically specifies a maximum value for the active power which should not be exceeded during operation. The achievable reactive power limit is here a limit which the wind turbine must be able to reach. If called upon, the wind turbine must therefore be able to feed in reactive power up to the reactive power limit.

[0014] It is particularly contemplated here that the two limits can be related. The achievable reactive power can be related in particular to the set active power. Both the active power and the reactive power describe here the power which is to be output by the wind power installation in principle. The relationship of the limits can be shown in particular in an active power / reactive power diagram, and wherein the limits form a surface or an enclosing surface.

[0015] For example, the reactive power limit can predetermine a reactive power value that is to be reached at least, but the reactive power value that is to be reached at least must be reached only within a likewise predetermined active power limit or region. For example, it can be provided that the predetermined reactive power value does not have to be reached at low active powers, but rather that the reactive power in kVAr, for example, must not be greater than the active power in kW.

[0016] The method is further designed such that a second power range is predefined at the grid connection point, the second power range covering a range of values ​​for active power and reactive power to be fed in, wherein the second power range has active power limits to be observed by the wind park at the grid connection point and has reactive power limits that can be reached by the wind park at the grid connection point.

[0017] In principle, the second power range is therefore preset at the grid connection point in the same manner and method as the first power range is preset at the wind energy device. However, the first power range and the second power range can be distinguished according to the value and, if necessary, also according to the mode or form. In particular, the power value of the second power range of the active power limit to be observed at the grid connection point and the reactive power limit that can also be achieved is greater than the value at each wind energy device, in particular, a multiple of the value at each wind energy device. Ideally, and only for the purpose of explanation, each limit of the second power range can be derived from the sum of all corresponding limits of the first power range of the relevant wind energy device. In practice, however, this can only be assumed ideally, but the influence of the transmission mechanism also plays a role. Usually, the grid operator presets what specific reactive power value the wind farm must reach under certain conditions at the grid connection point. The point is within the second power range that the wind farm must be able to achieve in principle, within the maximum range.

[0018] All wind turbines in the wind farm are then operated so that they each generate active power and reactive power taking into account the specifications of the wind farm regulator and transmit them to the grid connection point. It is also conceivable that, for example, one wind turbine or a plurality of wind turbines fail temporarily and then only the remaining wind turbines each generate the corresponding active power and reactive power and transmit them to the grid connection point. At least one of the wind turbines should do this.

[0019] It is also proposed that each wind energy installation exceeds the active power limit of the first power range to be observed. This can apply to all wind energy installations, multiple wind energy installations or at least one wind energy installation. It is therefore proposed that at least one or more wind energy installations specifically generate more power and transmit it to the grid connection point than is actually allowed or set based on the active power limit to be observed in the relevant first power range. As a result, the first power range is no longer observed by the wind energy installation, at least by one wind energy installation.

[0020] However, for this purpose it is simultaneously provided that the active power limit to be observed of the respective wind turbine is exceeded in each case, so that the second operating range is observed by the wind farm at the grid connection point.

[0021] The first power range is thus exceeded in a targeted manner, while the second power range is strictly adhered to. It has been recognized in particular that the first power range can be exceeded even without leaving the second power range. It has been recognized in particular that distortions of the power range can occur due to the influence of the transmission mechanism, so that leaving the first power range does not necessarily lead to leaving the second power range.

[0022] The wind turbines are each decoupled from the first power range, but only by taking into account the presettings of the wind farm regulator. The wind turbines are therefore guided at least in this respect by the wind farm regulator. The wind farm regulator can in particular monitor compliance with the second power range at the grid connection point and transmit corresponding presettings, in particular presettings for the active power and reactive power to be fed in, to the respective wind turbines.

[0023] This can also mean in particular that the wind farm controller detects the active power and reactive power currently fed in at the grid connection point and also determines the distance of the active / reactive power from the limit of the second power range and transmits corresponding presettings for the active power and reactive power to the respective wind turbines in this regard. This can also depend in particular on which active power presettings and reactive power presettings were previously transmitted to the respective wind turbines.

[0024] Thus, if it is recognized, for example, that the active power currently fed in at the grid connection point can still be increased by 10% due to the active power limits to be observed at the grid connection point, it can be implemented, for example, so that the total active power default is increased by 10%. Each wind turbine then checks whether it can still increase its active power by 10% or less and in this case exceed its first power range in a controlled manner. However, this is only an intuitive example and, for example, it can also be provided that the changes in the active power default and reactive power default at the individual wind turbines are individually ineffective.

[0025] It is also recognized that leaving the second power range at the grid connection point is to be avoided, in particular exceeding the active power limit to be observed, and can often even lead to a forced disconnection of the wind farm from the power supply grid. In particular, this can lead to safety precautions for opening corresponding safety protection devices.

[0026] However, such consequences are not immediately to be expected in the respective wind turbines of a wind farm. It is also recognized that the design of such predefined wind turbines, including active power limits to be observed in particular at the respective wind turbines, is in principle based on design limits which do not necessarily exist in the specific case.

[0027] The active power limit can be, for example, a protection against overheating. However, such overheating is usually not achieved in the case of a brief exceedance of an active power limit which is provided for protection purposes. Depending on how strongly the active power limit is exceeded, even a permanent exceedance can be acceptable, for example at particularly cold ambient temperatures. Whether such an active power limit is always strictly adhered to at a wind power installation can therefore depend on a number of factors, which are also described in more detail below and which can in principle provide for an individual assessment.

[0028] According to one embodiment, it is proposed that at least one, a plurality or all of the wind turbines are controlled in such a way that a reactive power limit of a first power range cannot be reached, whereas the wind park can reach a reactive power limit of a second power range.

[0029] This is based in particular on the consideration that the transmission mechanism has a particularly large influence on the transmission of reactive power. This can mean, for example, that the operating point at the wind turbine, which is defined by the active power and reactive power output by the wind turbine, is distorted by the transmission to the grid connection point, so that the operating point of the wind turbine leads to an operating point at the grid connection point with a greater reactive power component.

[0030] It has also been found that the output of very high active power components, in particular of wind turbines, in particular when the active power component is above the active power limit of the wind turbine, can only still allow the output of relatively low reactive power components. This can be caused, for example, by a current limitation which limits the apparent current. If high active power and thus high active current are output, the upper limit for the apparent current is almost reached and only a small reactive current can be output in addition until the apparent current reaches the mentioned current limit.

[0031] However, the transmission of the apparent current via the transmission means to the grid connection point may lead to a phase shift of the current, for example due to the inductive properties of the transmission line, which may lead to a higher reactive current component and thus to a higher reactive power component. This shift may have the effect that the wind energy installation may apparently output insufficient reactive power or may not be able to output sufficient reactive power, even though sufficient reactive power is still available or can be available due to the influence of the transmission infrastructure associated with the grid connection point.

[0032] This is also based on the knowledge that such reactive power presetting at the wind power installation is actually only used to ensure sufficient reactive power at the grid connection point. Usually, such reactive power output capability, which can also be called reactive power control capability, is only required at the grid connection point, i.e. to support the local voltage of the power supply network. Compliance with such reactive power limits at the wind power installation can be regularly determined here only as an indirect presetting for compliance with the reactive power achievable at the grid connection point.

[0033] The electric field regulator or the sensor provided for this purpose can check compliance with the active power limit at the grid connection point directly by measurement or evaluation of the measurement at the grid connection point, and propose another path for the reactive power to be complied with. In order to comply with the reactive power that can be achieved at the grid connection point, it is particularly proposed to take into account the characteristics of the transmission mechanism in a calculation manner or in a simulation. The characteristics can be measured or derived from physical conditions for this purpose. It is also possible to perform a derivation from the physical conditions, i.e. how long the corresponding transmission line is and what electrical characteristics it has, by means of simulation. In addition or alternatively, the phase angle obtained during the current and voltage measurement can be used to determine the transmission characteristics in terms of reactive power.

[0034] It is also considered that the change in reactive power caused by the transmission mechanism is derived from the power output of the wind power installation and the reactive power occurring at the grid connection point. To illustrate this with a simple example based on linear characteristics, for example, 10% of the reactive power output by the wind power installation will cause 20% of reactive power at the grid connection point. If a reactive power level of 40% must be achieved at the grid connection point, this means that the wind power installation must achieve a reactive power of 20%.

[0035] According to one embodiment, it is proposed that at least one, a plurality of or all of the wind power installations are respectively controlled so that they each output an output power having an active power component and a reactive power component for transmission to the grid connection point. For this purpose, it is proposed that the output power exceeds an active power limit of a first power range to be observed. The active power is therefore greater than the active power permitted according to the first active power limit to be observed at the wind power installation according to static design criteria.

[0036] In addition or alternatively, it is proposed that the output power has an apparent power value which is so large that the reactive power limit of the first power range cannot be reached without reducing the active power component. In this case, an excessively large active power component is thus generated and output at the wind power installation. An excessively large active power component can mean that, although the active power component is below the active power limit to be observed, an apparent power value is caused to be so large that the reactive power limit of the first power range, i.e. the reactive power limit of the first power range at the wind power installation, cannot be reached. The reactive power limit can only be reached if the active power component is reduced.

[0037] However, the possibility is also conceivable that the output active power is still so high that it exceeds the active power limit to be observed at the wind power installation.

[0038] However, for both or at least one of the two variants, it is proposed that the transmission device completely or partially causes the output power to change so that the second power range, i.e. the power range at the grid connection point, is maintained. The active power generation and output is thus intentionally almost exhausted and even overdriven at the wind energy installation, but in such a way that the resulting values ​​are maintained at the grid connection point.

[0039] For this purpose, known properties of the transmission mechanism, in particular the topology of the wind farm grid, or the topology of at least a part of the wind farm grid, can be taken into account when generating active and reactive power or when outputting it at the wind power installation. However, it is also conceivable that the wind farm regulator reports current information about the situation at the grid connection point to the wind power installation and that the wind power installation controls the overdriving of the power generation and output as a function of the current information.

[0040] In particular, it has been recognized that such an overstimulation, ie an increase, of the active power is possible and that the benefits can be increased thereby. In particular, strict adherence to the first power range, ie the power range at the wind power installation, has so far sometimes proven to be too cautious.

[0041] In particular, it has been recognized here that a separate consideration of the active power on the one hand and the reactive power on the other hand is not optimal, and it is therefore proposed to consider the output power with an active power component and a reactive power component, ie in particular with regard to the first power range to be maintained and also the second power range.

[0042] According to one embodiment, it is proposed that the transmission device reduces the output active power component of the output power output for transmission by heat dissipation, so that the active power limits of the second power range are observed. In particular, for example, ohmic losses or ohmic properties of the transmission device can be known and taken into account when the individual wind turbines generate and output active power components during operation outside the first power range.

[0043] In particular, it has been recognized that active power can be wasted, so that less power is extracted from the wind and converted into electrical active power than would be possible without taking such losses into account. In this case, it is possible to comply with an active power range at the wind energy installation for the purpose of hypothetical protection of the grid connection point, even though less active power ultimately arrives at the grid connection point, so that the possible active power range at the grid connection point is not exhausted. It has been recognized that such an exhaustion of the possible active power range at the grid connection point can mean that the limits at the wind energy installation are exceeded. However, this can be a meaningful option if exceeding the active power limits is permitted to a certain extent.

[0044] In addition or alternatively, it is proposed that the transmission mechanism causes a change in the reactive power component of the output power output so that the reactive power limit of the second power range is reached, so that in particular a reactive power value is reached which is typically preset by the grid operator and is within the reactive power limit of the second power range. It has also been recognized here that in some cases it is not necessary to provide accessibility to the reactive power limit at the wind power installation, because the transmission mechanism in particular causes a phase shift of the transmitted current, but the reactive power limit of the second range, i.e. the grid connection point, can be reached. In this case, it is also possible to feed in a higher active power, because in this respect active power and reactive power are linked, and if the reactive power can be reduced, this can result in an increase in active power being achieved thereby.

[0045] According to one embodiment, the sum of all output powers of wind energy installations before transmission by means of the transmission means does not comply with the second power range, but rather the sum of all output powers transmitted to the grid connection point complies with the second power range at the grid connection point. This is based on the knowledge that the active power limit can be complied with, in particular at the grid connection point, despite all wind energy installations together generating and transmitting to the grid connection point more active power than is permitted at the grid connection point. However, the same can also apply to reactive power, i.e., it is possible that all wind energy installations together cannot reach the reactive power limit at the grid connection point with the sum of their achievable reactive power, but can reach the reactive power limit at the grid connection point after transmission via the transmission means of the wind farm.

[0046] According to one design, one, more or all wind turbines exceed the active power limit of the first power range to be observed, i.e. the active power limit at the respective wind turbine, according to a plurality of check conditions. Therefore, the active power limit to be observed cannot be easily exceeded, but a special check is required to determine whether this is acceptable.

[0047] As at least one check condition, compliance with the field presetting of the field regulator is provided. The field regulator can therefore make presettings, for example, to distribute active power upper limits to the individual wind turbines. However, a wind turbine exceeds the active power limit to be complied with only as long as the check condition, i.e. compliance with the field presetting of the field regulator, is ensured.

[0048] Additionally or alternatively, compliance with an installation condition of the respective wind power installation is checked as at least one check condition. Such an installation condition is explained in more detail below and may relate, for example, to compliance with a maximum temperature at a component of the wind power installation.

[0049] Preferably at least one electric field presetting and at least one device condition are checked, thus two condition types.

[0050] Preferably, at least two plant conditions are checked here. For example, it is checked whether the temperature range is observed at the wind power plant and whether the mechanical load limits are observed at the wind power plant. In particular, it has been recognized that the active power limits of the first power range to be observed, i.e. the active power limits of the first power range to be observed at the wind power plant, should not be exceeded rashly, and that completely different load limits should be taken into account for this purpose, which can also be independent of each other, so that the consideration of a single condition is not sufficient or is not adequate. In particular, it has been recognized that, using the above example, the mechanical limits can be observed without the thermal limits, and vice versa. Therefore, preferably at least two plant conditions are checked.

[0051] According to one embodiment, it is proposed that the device condition is one of the conditions described below. If multiple device conditions are checked, this can correspondingly be multiple conditions of the conditions described below.

[0052] A feasible installation condition is compliance with an extended power range at the respective wind turbine installation, which is at least partially greater than a first power range of the same wind turbine installation. A further power range is therefore provided around the first power range, which makes it possible that, if the first power range is exceeded, the further power range is not exceeded to any degree. This makes it possible to create a first safety margin.

[0053] Another or other plant condition may be compliance with a predetermined maximum temperature in the respective wind power plant. For this purpose, critical components may be considered, in particular for power generation or feed-in. These critical components may be, for example, the temperature at the power semiconductor switches for frequency conversion. The temperature at the windings of the generator is also considered.

[0054] It has been recognized in particular that some power limits for device protection are actually intended to avoid overheating. In this regard, such power limits are also meaningful for overheating protection and should not be ignored lightly. However, it is still possible to allow the power to exceed the relevant temperature or when taking into account multiple temperatures.

[0055] On the one hand, the following concept applies: the increased power, in particular the accompanying increased current, does not immediately lead to overheating, since most systems are more sluggish in their thermal behavior than in their electrical behavior. In addition, the temperature behavior is also dependent on the ambient temperature. If the ambient temperature is therefore, for example, relatively low, ie, below the design temperature, a stronger or longer overheating may be acceptable before overheating occurs.

[0056] Another or alternative condition is to comply with a predetermined maximum current in the corresponding wind energy installation. This maximum current can be the current in the generator, in particular the stator current. From this current, a specific load for the corresponding element, such as the element in the example of the generator, can be generated.

[0057] However, output currents output by wind turbines are also conceivable, for example. Such output currents may also cause direct loads and thus require a check on compliance with a predefined maximum current as a system condition.

[0058] As a further or alternative condition, it is proposed that a predetermined maximum mechanical load of the respective wind energy installation is observed. In general, the idea here is that an excessively high active power output can also mean that a correspondingly high power is extracted from the wind. This causes corresponding mechanical loads on the relevant components. In particular, the rotor blades and the rotor hub are mentioned here. In the case of transmission-free installations, the shaft journals are also considered, which carry the rotor hub together with the rotor blades and which also carry the generator, at least the rotor of the generator. The transitions of the mentioned elements and also in particular the other fastenings of the generator at the remaining pod can also be subjected to strong mechanical loads in the case of high active power output.

[0059] In particular, it has also been recognized that exceeding mechanical limits is more intolerable than exceeding power limits, which can lead to temperature increases only after a time delay. In particular, it has been recognized that exceeding the active power limit to be observed can at least temporarily lead to well-tolerated temperatures, especially at ambient temperatures below the design temperature, while exceeding the active power limit to be observed can simultaneously lead to intolerable mechanical loads.

[0060] In addition, strong mechanical loads cannot be tolerated, especially if they cause a breakage even once, whereas thermal loads often cause the service life of the wind power installation to be reduced. This is acceptable, in particular, if the reduction in service life results in a total service life that is still longer than the authorized operating time.

[0061] It is particularly preferably provided that the active power limit of the first power range is predefined and / or monitored as a function of a predicted service life of the wind power installation.

[0062] Preferably, it is proposed that only when at least one criterion of the above-mentioned device conditions forming the condition list is observed, then the first power range is allowed to be exceeded while observing the extended power range. In particular, it is proposed that this is allowed as long as at least two criteria of the condition list are observed and further preferably as long as all criteria of the condition list are observed.

[0063] In particular, simplified check criteria are used here, wherein firstly exceeding the first power range is limited by another power range. In this way, a safety limit is set for exceeding in the first step. Then, it is additionally checked whether at least one of the other conditions is complied with and if at least one condition, a plurality of conditions or all the remaining conditions are complied with, the first power range can be exceeded. Thus, additional active power can be fed in if necessary, while taking into account binding conditions that thus avoid damage to the equipment. Of course, in addition, the following criteria should also always be complied with: the second power range is complied with at the grid connection point. This can be achieved, for example, by complying with the desired value or limit value transmitted to the relevant wind energy device by the electric field regulator.

[0064] It is therefore preferably provided that, when the extended power range is observed, the first power range is always allowed to be exceeded if the second power range is also observed at the grid connection point, if at least one of the criteria of the mentioned condition list is observed, in any case if a plurality or all of the criteria of the condition list are observed. This makes it possible to achieve a positive and complete check. In particular, it has been recognized that the mentioned conditions of the condition list, if they are observed in any case, are sufficient to define such an exception for exceeding the first power range.

[0065] In addition or alternatively, it is proposed that, if a predetermined maximum mechanical load is observed and in particular the remaining criteria of the condition list, or at least one of them, are observed, then exceeding the extended power range is permitted for a predetermined exception duration. Thus, even if the extended power range is exceeded, more power can still be fed in if necessary. By observing the conditions and in particular by observing the predetermined maximum mechanical load, damage to the device can be ruled out.

[0066] In addition or alternatively, it is proposed that the predetermined maximum temperature is predetermined according to a predetermined tolerance period. This is based in particular on the idea that excessively high temperatures usually lead to intolerable damage only in the case of continuous load or at least longer load, and therefore it is proposed to predetermine the time limit of the predetermined maximum temperature by means of the predetermined tolerance period.

[0067] Preferably, it is proposed that this is further improved, that is, at least one predetermined first maximum temperature is preset in the predetermined first tolerance period and at least one predetermined second maximum temperature is preset in the predetermined second tolerance period, wherein the predetermined first maximum temperature is lower than the predetermined second maximum temperature and the predetermined first tolerance period is longer than the predetermined second tolerance period. In this way, different maximum temperatures, i.e., temperature limit values, can be preset in durations of different lengths.

[0068] In this case, a correspondingly longer first tolerance period is predetermined for a lower first maximum temperature and the predetermined second maximum temperature can be selected to be higher, but only for a shorter time, ie only for the shorter predetermined second tolerance period.

[0069] In this case, the idea is based in particular on the fact that, situation-dependently, i.e., in particular depending on the overall situation of the wind farm and / or at the grid connection point, a generally smaller power increase may be expedient for a longer period of time, whereas in other situations, not much time is available and as much power as possible should be fed in during this time. For example, if the power exceeded at the wind energy installation is strongly limited by a relatively small margin due to compliance with the second power range at the grid connection point, a correspondingly smaller power increase is more sensible, which is then preferably carried out for as long as possible.

[0070] In addition or alternatively, it is proposed that a predetermined maximum current may be exceeded for a predetermined second exceptional time period if a predetermined maximum mechanical load is observed and in particular the remaining criteria of the condition list are observed. It has been recognized that a time limit may also be meaningful for the maximum current. On the one hand, high currents may sometimes only lead to intolerable damage or no longer tolerable impairment after a longer period of time, and on the other hand, high currents may also lead to thermal loads, i.e. to thermal loads at components whose temperature is not measured, so that the temperature cannot be checked and the current cannot be monitored instead.

[0071] It has also been recognized that mechanical loads should also be observed and that in particular high currents can lead to mechanical loads. This applies in particular to high stator currents which can lead to large generator torques. However, this can also apply to other currents which can indirectly lead to high generator currents and generator torques, for example.

[0072] In addition or alternatively, it is proposed in a completely general manner that compliance with a predetermined maximum mechanical load must always be ensured. This is based in particular on the recognition that the time considerations proposed for the thermal load and explained above are less suitable for the mechanical load. It has also been recognized that the mechanical load is only reached for this purpose, but only with a significant excess of power, so that the observation of the maximum mechanical load allows a relatively large excess of the active power limit to be complied with, but for this purpose a further excess or mechanical overload is relatively unacceptable.

[0073] According to one embodiment, it is proposed that the electric field preset includes at least one electric field preset value output to each wind power device. The electric field preset value can be an active power maximum value to be observed by each wind power device, or it can be a reactive power value to be reached by each wind power device. It is also possible to propose a plurality of electric field preset values, wherein at least one electric field preset value is an active power maximum value to be observed or has an active power maximum value to be observed as a value, and at least one other electric field preset value is a reactive power minimum value to be reached by each wind power device or has this value. In order to comply with the second power range, it is therefore proposed that the electric field regulator generates an electric field preset value corresponding thereto and forwards at least one electric field preset value to the wind power device.

[0074] It is preferably proposed that at least one electric field preset value is determined by the electric field regulator as a function of the second power range and the power currently fed in at the grid connection point. The electric field regulator thus checks the extent to which the second power range is currently being observed and can adjust the electric field preset value accordingly. If the electric field regulator detects, for example, that an active power is currently being fed in at the grid connection point, which is 20% below the active power limit at the grid connection point, the electric field preset value can be increased accordingly if the electric field preset value relates to an active power maximum value to be observed. It is preferably proposed that an upper limit is provided for this variable active power maximum value regularly re-determined by the electric field regulator.

[0075] Preferably, at least one electric field preset value is output as a relative value. In particular, a percentage value is considered here, which relates to the rated power of the wind energy device. Different wind energy device variables can thus be considered in a simple manner. In particular, it can be proposed here that if the active power fed in at the grid connection point is below the active power limit at the grid connection point, the active power maximum value to be observed for each wind energy device is set to a value higher than 100%. As an upper limit, for example, a value of 120% can be proposed in total, assuming that each wind energy device cannot or can only achieve such a strong excess of the active power limit to be observed. It is also considered that such a value is determined by simulation or corresponding device analysis.

[0076] However, according to one embodiment, it can be provided that these field default values, at least one of which is determined individually for each wind turbine, are determined. This allows specific power values ​​or reactive power values ​​to be set, but also allows for individual considerations to be taken into account, with the field controller determining and outputting relative, in particular percentage, values. By using such individualized values, it can be taken into account, for example, that different maximum values ​​are meaningful for different wind turbines.

[0077] According to the invention, a wind farm is also proposed. Such a wind farm has a plurality of wind energy installations and is fed into the power supply grid at a grid connection point. The grid connection point can be regarded as a limit and part of the wind farm.

[0078] The wind farm has a transmission mechanism for connecting the wind power device to the grid connection point, and in particular the wind power device is connected to the grid connection point via the transmission mechanism. Such a transmission mechanism is particularly designed as a transmission line. However, other elements such as transformers or switching mechanisms may also be present.

[0079] In addition, a wind farm regulator is proposed, which is configured to transmit an active power preset and a reactive power preset to a wind power installation. The active power preset and the reactive power preset can be referred to as presets of the wind farm regulator. The wind farm regulator can thereby preset how much active power the wind power installation is allowed to generate and transmit and / or how much reactive power the wind power installation must be able to generate and transmit.

[0080] Each of the wind turbines is characterized by a first predetermined power range, which covers a range of values ​​for the active power and reactive power to be fed in, i.e., a range of values ​​for the active power and reactive power to be fed in for the respective wind turbine. The first power range can be differentiated between the wind turbines. If only identical wind turbines are installed in a wind farm, it is also conceivable that no differentiation is made between the first power ranges.

[0081] The first power ranges are each characterized in that they have active power limits to be observed by the wind power installations and in that they have reactive power limits achievable by the wind power installations. To clarify the different limits, reference is also made to the correspondingly described embodiments of the above specific embodiments of the method for feeding in.

[0082] The grid connection point is characterized by a predefined second power range, which covers a value range for active power and reactive power to be maintained, wherein the second power range has an active power limit to be maintained by the wind farm at the grid connection point and a reactive power limit that can be achieved by the wind farm at the grid connection point. For the explanation, reference is also made here to the above-described specific embodiments of the method for feeding in.

[0083] At least one, a plurality of or all of the wind power installations have an installation control device, which is respectively configured to control the relevant wind power installation according to the presettings of the electric park regulator. Such an installation control device can be configured in particular, for example, to have a corresponding receiving device or to be connected to such a receiving device, to receive the mentioned presettings of the electric park regulator and then to control the relevant wind power installation in relation thereto.

[0084] Furthermore, at least one feed-in device is provided in each case, which is configured to generate active power and reactive power in accordance with the specifications of the electric field regulator and to transmit it to the grid connection point.

[0085] The device control device is further configured to control the respective wind energy device so that it exceeds the active power limit of the first power range to be observed by it, but only exceeds the active power limit to be observed in each case, so that the wind farm complies with the second power range at the grid connection point. This can be achieved in particular by the wind energy device complying with the preset of the electric park regulator for this purpose. It is particularly proposed here that the device control device and the electric park regulator are configured to ensure that the wind energy device complies with the second power range at the grid connection point. This can be a cooperation between the electric park preset determined and transmitted by the electric park regulator and the control of the respective wind energy device carried out in this connection by means of the device control device.

[0086] In particular, it is proposed that the wind farm is configured to carry out at least one method according to at least one of the above-mentioned embodiments. The corresponding device control device of the electric farm regulator and / or the wind energy device is configured accordingly for this purpose. Such a configuration can include that a corresponding processing computer or control computer is provided, and the corresponding method or the corresponding part of the method is programmed on the processing computer or control computer. In addition, there are corresponding transmission means and / or evaluation means and / or sensors that can realize or at least support the implementation of the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The present invention will be explained in detail below based on embodiments by way of example with reference to the accompanying drawings.

[0088] Figure 1 The wind power installation is shown in a perspective view.

[0089] Figure 2 A wind park is shown in a schematic diagram.

[0090] Figure 3 The first power range and the second power range are schematically shown in the PQ diagram. DETAILED DESCRIPTION

[0091] Figure 1A wind power installation 100 is shown having a tower 102 and a nacelle 104. A rotor 106 having three rotor blades 108 and a spinner 110 is arranged on the nacelle 104. During operation, the rotor 106 is set into rotational motion by the wind and thereby drives a generator in the nacelle 104.

[0092] The wind power installation 100 further comprises a control unit 130 which is coupled to a communication unit 132 and has a communication interface 133 for communicating with a central farm control unit. For detecting the external temperature, an external temperature sensor 134 is provided which can transmit its measured values ​​to the control unit 130 for evaluation or which can be controlled by the control unit 130 for the measurement. Furthermore, a transformer 136 is also provided which is associated with the wind power installation 100 and can be referred to as a wind power installation transformer.

[0093] Figure 2 A wind farm 112 is shown with three wind turbines 100, which can be identical or different. The three wind turbines 100 therefore represent essentially any number of wind turbines of the wind farm 112. The wind turbines 100 provide their power, i.e., in particular the current generated, via a wind farm grid 114. Here, the currents or powers generated by the individual wind turbines 100 are added together. In a wind farm with a grid connection point, which can also be synonymously referred to as a grid connection point or PCC, a transformer 116 is provided at the upper grid or the highest grid, which transformer steps up the voltage in the farm so that it can then be fed into the grid of the grid operator 120 at the grid connection point 118. Figure 2 This is only a simplified view of a wind farm 112, which does not show a control device, although it is of course present. The farm grid 114 can also be designed differently, for example, in which a transformer is also present at the output of each wind energy installation 100, for example, to cite only one further exemplary embodiment.

[0094] Figure 2 Also shown is a central wind farm control unit 140, which can also be referred to as a wind farm regulator or wind farm control device. A wind farm measuring unit 141 is also provided, which can measure the current and voltage at the grid connection point 118. The active power and reactive power currently fed in at the grid connection point 118 can be detected from this. The wind farm control unit or wind farm regulator receives this information and can transmit desired values ​​or other information based on this information to the individual wind energy installations 100. Figure 2 The spatial separation shown in is only for better illustration, where the transmission of expected values ​​or other information is important. The electric field control unit 140 and the electric field measuring unit 141 can also be arranged at the same location, ie in particular at the feed point, and preferably form one unit. Figure 3 Two PO diagrams are shown schematically, namely a first power range 401 in the left diagram and a second power range 402 in the right diagram. In particular, it should be clearly shown in the left diagram that the first power range 401 is delimited to the upper limit by an active power limit 411, which therefore indicates the maximum active power in continuous operation and under design conditions. Usually, this is the rated power P nenn . A possible boost range 416 is shaded above. If necessary, this boost range can be fully utilized. In this boost range 416, it is therefore possible to leave the first power range 401. However, this only occurs briefly and / or under certain boundary conditions, such as, in principle, low temperatures. However, this is valid as long as the sum of all active powers does not leave the maximum active power limit of the second power range 402 at the grid connection point, taking into account the changes and / or distortion effects caused by the transmission mechanism of the wind farm.

[0095] The above-mentioned boost range 416 forms an extended power range and is bounded upwards, for example, by a circular arc, which is bounded by the maximum current load of the power semiconductors of the inverter generating the current. Correspondingly, the limit, shown for example by a dotted line, forms a limit referred to here as power semiconductor limit 460. Since the limit is predetermined by the current level, it essentially forms a circle around the origin of the PQ diagram. For the current limit or the resulting current load, the phase angle of the current is essentially insignificant.

[0096] The same applies to the likewise drawn continuous current limit 462, which can be predefined in particular by the transformer. The continuous current limit 462 is also shown at a distance from the power switch limit 460 and thus from the boost range 416. The continuous current limit should not be reached or exceeded if possible.

[0097] The lifting range 416 can also be additionally or alternatively preset by a predetermined first maximum temperature in a predetermined first tolerance period, wherein the continuous current limit 462 can then be preset by a predetermined second maximum temperature in a predetermined second tolerance period. In this case, the temperature limit can be exceeded up to the predetermined first maximum temperature for a longer time than up to the predetermined second maximum temperature. In addition, a mechanically determined limit 464 is also plotted, which indicates the maximum active power, which is determined by an upper limit for the load of the mechanical load, such as the rotor blades. The mechanically determined limit 464 describes the predetermined maximum mechanical load and therefore essentially only relates to the active power and is therefore formed as a horizontal line parallel to the Q axis.

[0098] However, in addition to all the limits to be observed according to the diagram on the left, it must be ensured that the second power range 402 is not left. Figure 3 The variant shown by way of example in the diagram on the right in FIG. 4 has an active power lower limit 425 close to the Q axis, which essentially indicates that the feed-in of reactive power in a regulated form is only particularly necessary from a certain minimum active power. However, this lower limit is a special case, so that it does not have to be present in other embodiments. In this respect, it is not dependent on the lower limit.

[0099] In particular, a solution is now being proposed which enables the operation of a wind power installation at least temporarily at an active power higher than the rated power.

[0100] This can be used as a goal to achieve the best possible utilization of the PQ control capacity of the wind power installation, while at the same time satisfying the grid connection regulations by the wind farm as a whole. In particular, the profitability of the wind power installation can also be increased without compromising the compliance with the grid connection regulations (grid codes).

[0101] This also solves the problem that the PQ diagrams of wind power plants have been essentially cut off horizontally at rated power so far. This does not allow operation above rated power. However, it has been recognized that such strict limitations are not necessarily necessary. The limits described at rated power are not necessarily required in every case to meet the regulations at the grid connection point (PCC), and operation with an instantaneous active power above rated power is generally not technically impossible, as has now been recognized.

[0102] It has been recognized that if a wind turbine can at least capture and convert the rated wind and does not have to output its reactive power at any given time, it can be operated at an operating point in which its active power P exceeds its rated active power (P nenn ) For this purpose, it is proposed that the wind farm regulator, ie the central farm control unit, ensures at the grid connection point that the wind farm feeds in the required reactive power in total and that at the same time the maximum permissible active power at the grid connection point of the wind farm is not exceeded.

[0103] It has also been recognized that the active power of individual wind turbines can be increased above their rated power until at least the lowest of the following possible limits is reached:

[0104] a. Active power limit of the generator.

[0105] b. Apparent power limits of converters, DC cables or other components in the wind energy installation which limit the apparent power and are used in the wind energy installation.

[0106] c. The apparent power limit of the transformer associated with the wind energy installation.

[0107] d. Mechanical load limits which in particular form the load limits of the rotor blades or the tower.

[0108] It has also been found that, for example, the use of thermal inertia in generators or transformers can even cause temporary overloading of the components involved. It has also been found that the occurrence of rated wind and the simultaneous use of high or even maximum reactive power do not usually occur together permanently.

[0109] In order to be able to implement this increased operation without damage, in particular out of the first power range, it is proposed to monitor all critical components thermally or mechanically and, if necessary, to reduce the active power operating point to a normal characteristic curve.

[0110] It has also been recognized that in a wind farm all wind turbines are simultaneously subjected to the rated wind and each provide a rated active power (P nenn ) is only very rarely required, and the rated active power can also be referred to as the rated power in simplified and synonymous terms. It is also rare that a maximum reactive power is required by a wind farm at the grid connection point. However, to date, each individual wind energy installation is limited to its individual limits, in particular to its individual rated power P N As an upper limit, even if the maximum wind farm permitted by the grid operator (P N _ WP ) can be fed in more active power, even if, for example, other wind turbines do not fully utilize their maximum producible rated power (P N _ WEA ).

[0111] It is taken into account here that the grid connection regulations, which are also generally referred to as grid codes, usually relate to the maximum permissible feed-in power at the grid connection point of the wind farm. In this case, usually for each active power operating point of the wind farm, a reactive power control range predefined by the grid operator must be provided for the active power operating point. As long as the wind farm as a whole complies with the requirements of the grid connection regulations at the grid connection point, it may be permitted, depending on the structure to be used and the electrical permit, for individual wind energy installations to be operated at a power higher than their rated power under certain conditions.

[0112] If the relationships proposed according to the invention are taken into account, then, depending on the circumstances, further benefits can be achieved for the wind farm. In this case, better utilization of the generally different wind conditions in the wind farm can also be achieved.

[0113] In addition, the capacity of the grid for delivering power to consumers at the grid connection point and in the upstream grid is better utilized. Specifically, the operating mechanism at the grid connection point and on the other side thereof can achieve higher hours with higher utilization, which is economically advantageous for grid operation.

[0114] The additional benefits that can be achieved for a wind power installation can depend on the frequency of strong wind conditions at the relevant site. The frequency of the maximum reactive power call-up also plays a role, as does its time dependence on the wind conditions and the outside temperature.

[0115] If the operating range of an individual wind turbine is limited to the rated power, it is ensured that the technical components are not overloaded, but if necessary a technically feasible maximum value is also extracted from the hardware for this purpose.

[0116] A wind farm regulator is usually present in every newly established wind farm in the meantime. Retrofitting is usually technically feasible even in the case of old stock. This allows individual wind energy installations to be operated above their rated power while still complying with the grid code conditions and, in particular, ensuring a maximum active power at the grid connection point in any case. It is therefore preferably provided that a wind farm regulator is used for this purpose and that the wind farm regulator is programmed accordingly.

[0117] It is therefore proposed that wind turbines are explicitly allowed to be operated also outside the nominal PQ control range. In particular, it is proposed that if the current wind speed at the relevant wind turbine allows more active power to be fed in than the rated power, this can be done as long as other limiting factors do not prohibit this.

[0118] The following are listed as such limiting factors:

[0119] a. Limits within the wind power plant when, for example, the magnetization of the generator has a maximum value; the bending of the rotor blades has a maximum value, the transformer temperature reaches a maximum value, or the temperature of the DC cable reaches a maximum value, to name only a few examples. In the case of electrical components that are in the power flow from the generator to the supply grid, i.e. to the grid connection point, it is preferably not the rated current or the permanent maximum current that is decisive here, but the temperature can also be decisive, and for this purpose it is proposed to dynamically monitor the temperature of the relevant components.

[0120] b. Limiting signals of the wind park regulator in order to prevent the permitted total active power of the wind park from being exceeded at the grid connection point.

[0121] c. The reactive power required by the grid operator to be taken into account. In this case, the wind farm controller causes corresponding control instructions to be sent to the individual wind energy installations, which cause corresponding reactive power output of the wind energy installations. It should be taken into account whether the relevant wind energy installation is already conducting the maximum apparent current at the said time. For this case, it is proposed to shift the operating point accordingly, that is, in particular, to shift the operating point along the curve indicating the maximum apparent power. (S max In this case, it is proposed to give priority to reactive power, since reactive power is usually a mandatory precondition of the grid operator, whereas the active power feed-in is dependent on the current wind speed in an accepted manner.

Claims

1. A method for feeding electrical power into a power supply network at a grid connection point (118) by means of a wind farm (112) having a plurality of wind energy installations (100), wherein - the wind energy installation (100) is connected to the grid connection point (118) via a transmission mechanism, - a wind farm regulator is provided for transmitting an active power preset and a reactive power preset to the wind energy installation (100), a first power range (401) is predefined at each of the wind power installations (100), the first power range covering a range of values ​​for active power and reactive power to be fed in and being able to differentiate between the wind power installations (100), wherein the first power range (401) has: - an active power limit (411) to be observed by the wind energy installation (100), and - a reactive power limit achievable by the wind energy installation, - a second power range (402) is predefined at the grid connection point (118), the second power range covering a range of values ​​for active power and reactive power to be fed in, wherein the second power range (402) has: - an active power limit (411) to be observed by the wind farm at the grid connection point (118), and - a reactive power limit that can be achieved by the wind farm at the grid connection point (118), - at least one, a plurality of or all of the wind energy installations (100) generate active power and reactive power in each case taking into account the specifications of the park regulator and transmit the active power and reactive power to the grid connection point (118), at least one, a plurality or all of the wind turbines have exceeded an active power limit (411) of the first power range (401) to which they are subject, The active power limit (411) to be adhered to is respectively exceeded, so that the second power range (402) is adhered to by the wind park at the grid connection point (118).

2. The method according to claim 1, It is characterized in that At least one, a plurality of or all of the wind power installations (100) are controlled so that the reactive power limit of the first power range (401) is not reached and the wind farm can reach the reactive power limit of the second power range (402).

3. The method according to claim 1 or 2, It is characterized in that At least one, a plurality of or all of the wind energy installations (100) are controlled respectively so that they respectively output an output power having an active power component and a reactive power component for transmission to the grid connection point (118), wherein - the output power exceeds the active power limit (411) to be observed in the first power range (401), and / or the output power has an apparent power value which is so large that the reactive power limit of the first power range (401) cannot be reached without reducing the active power component, wherein The transmission mechanism completely or partially causes the output power to be changed such that the second power range is adhered to (402).

4. The method according to claim 1 or 2, It is characterized in that - the transmission mechanism reduces the output power output for transmission or the output active power component of the output power output for transmission or the output active power component by heat consumption, so that the active power limit (411) of the second power range (402) is observed, and / or The transmission mechanism causes a change in the output power of the output or a reactive power component of the output power of the output or the reactive power component such that a reactive power limit of the second power range (402) is reached.

5. The method according to claim 1 or 2, It is characterized in that the sum of all output powers of the wind energy installation (100) before transmission by means of the transmission device does not comply with the second power range (402), but rather, - the sum of all output powers transmitted towards the grid connection point (118) complies with the second power range (402) at the grid connection point (118).

6. The method according to claim 1 or 2, It is characterized in that At least one, a plurality of or all of the wind power installations (100) exceed an active power limit (411) of the first power range (401) to be observed by them, respectively, according to a plurality of check conditions, wherein - as at least one check condition, checking compliance with an electric field presetting of the electric field regulator, and / or As at least one check condition, compliance with an installation condition of the respective wind power installation is checked.

7. The method according to claim 1 or 2, It is characterized in that - Equipment condition or the equipment condition is a condition selected from the following list of conditions: - an extended power range is observed at the respective wind turbine, said extended power range being at least partially greater than a first power range of the same wind turbine (100), - compliance with a predetermined maximum temperature in the respective wind energy installation, - compliance with a predetermined maximum current in the respective wind energy installation (100), and - a predetermined maximum mechanical load of the respective wind power installation (100) is adhered to.

8. The method according to claim 7, It is characterized in that The corresponding wind energy device (100) is controlled so that - exceeding the first power range is permitted while complying with the extended power range only if at least one criterion of the condition list is complied with (401), - if the predetermined maximum mechanical load is observed, exceeding the extended power range is permitted for a predetermined exception duration, - said predetermined maximum temperature is predetermined according to a predetermined tolerance duration.

9. The method according to claim 1 or 2, It is characterized in that - an electric field preset or the electric field preset comprises at least one electric field preset value output to each wind power device (100), wherein the electric field preset value is selected from the following list: - a maximum active power value to be observed by each wind energy installation (100), and - a minimum reactive power value to be achieved by each wind energy installation (100), wherein The at least one wind farm default value is determined by the wind farm regulator as a function of the second power range (402) and the current power fed in at the grid connection point (118) and / or is determined individually for each wind turbine.

10. The method according to claim 2, characterized in that The wind park can achieve a reactive power value required at a point in time by a grid operator (120) up to the reactive power limit.

11. The method according to claim 6, characterized in that - Checking at least one electric field preset and at least one device condition.

12. The method according to claim 6, characterized in that - Check at least one electric field preset and at least two device conditions.

13. The method according to claim 8, It is characterized in that - Exceeding the first power range is only permitted if the extended power range is observed, as long as at least two criteria of the condition list are observed (401).

14. The method according to claim 8, It is characterized in that As long as all criteria of the condition list are met, exceeding the first power range is permitted only if the extended power range is observed (401).

15. The method according to claim 8, It is characterized in that If the predetermined maximum mechanical load is observed and the remaining criteria of the condition list are observed, exceeding the extended power range is permitted for a predetermined exception duration.

16. The method according to claim 8, It is characterized in that - presetting at least one predetermined first maximum temperature during a predetermined first tolerance period, and - at least one predetermined second maximum temperature is predefined during the predetermined second tolerance period, wherein - the predetermined first maximum temperature is lower than the predetermined second maximum temperature and the predetermined first tolerance duration is higher than the predetermined second tolerance duration, - allowing the predetermined maximum current to be exceeded for a predetermined second exception duration if the predetermined maximum mechanical load is observed, and / or - Compliance with the stated predetermined maximum mechanical loads must always be ensured.

17. The method according to claim 16, It is characterized in that If the predetermined maximum mechanical load is observed and the remaining criteria of the condition list are observed, then exceeding the predetermined maximum current is permitted for a predetermined second exception period.

18. The method according to claim 9, It is characterized in that The at least one electric field preset value is used as the rated power (P nenn )’s relative value output.

19. The method according to claim 9, It is characterized in that The at least one electric field preset value is used as the rated power (P nenn ) is output as a percentage.

20. A wind farm having a plurality of wind energy installations for feeding electrical power into a power supply grid at a grid connection point (118), the wind farm comprising: - a transmission device for connecting the wind energy installation to the grid connection point (118), - a wind farm controller for transmitting an active power specification and a reactive power specification to the wind turbine, wherein Each of the wind turbines is characterized by a first predetermined power range (401), which covers a range of values ​​for active power and reactive power to be fed in and can be differentiated between the wind turbines, wherein the first predetermined power range (401) has: - an active power limit (411) to be observed by the wind energy installation (100), and - a reactive power limit that can be achieved by the wind energy installation (100), The grid connection point (118) is characterized by a predefined second power range, which covers a range of values ​​for the active power and reactive power to be fed in, wherein the second power range (402) has: - an active power limit (411) to be observed by the wind farm (112) at the grid connection point (118), and a reactive power limit achievable by the wind farm (112) at the grid connection point (118), - at least one, a plurality or all of the wind power installations (100) - each having an installation control device, which is configured to control the associated wind energy installation (100) according to the presetting of the electric field regulator, and - each having a feed-in device, which is configured to generate active power and reactive power according to the specification of the electric field regulator and transmit the active power and reactive power to the grid connection point (118), wherein the device control device is configured to, - controlling the respective wind energy installation in such a way that it exceeds the active power limit (411) of the first power range (401) to be observed by it, and wherein The installation control device and / or the wind farm regulator are configured to control the respective wind energy installation (100) so that only an active power limit (411) to be observed is exceeded in each case, so that the second power range (402) is observed by the wind farm at the grid connection point (118).

21. The wind farm according to claim 20, It is characterized in that The wind farm (112) is configured to perform at least one method according to any one of claims 1 to 19.

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