Method for operating a wind farm and wind farm implementing this method
Abstract
The method involves setting the electrical power of the wind park or one or more wind power systems in a range of 0 to 100 per cent of the available power by means of a data processing device connected to at least one wind power system control input. The demanded power is set depending on the total available power of the wind park. The controller of the supply system can set the power output by the wind park. An independent claim is also included for the following: a wind park and a wind power system.
Term
Term ended
Expired 21 September 2022, 4 years ago.
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7 claims: 1 independent, 6 dependent
- 1Sposób eksploatacji farmy wiatrowej zawierającej wiele instalacji wiatrowych, połączonej z siecią energetyczną, którą zasila mocą elektryczną wytwarzaną przez tę farmę wiatrową i ta farma wiatrowa i/albo co najmniej jedna z jej instalacji wiatrowych posiada wejście sterowania, za pomocą którego moc elektryczna farmy wiatrowej albo jednej lub więcej poszczególnych instalacji wiatrowych może zostać nastawiona na dostarczanie w zakresie 0 i 100% mocy dyspozycyjnej, w szczególności mocy znamionowej, przy czym wartość zadaną nastawia się za pomocą urządzenia przetwarzania PL 212 098 B1 danych połączonego z wejściem sterowania, za pomocą którego wartość zadaną ustawia się w zakresie od 0 do 100%, w zależności od mocy, którą cała farma dostarcza do sieci energetycznej na swoim wyjściu zasilania, zaś operator (zakład energetyczny) energetycznej sieci zasilającej, do której przyłączona jest farma wiatrowa, nastawia moc produkowaną w farmie wiatrowej za pomocą wejścia sterowania, znamienny tym, że zawiera etap, w którym ogranicza się moc dostarczaną przez instalacje wiatrowe do maksymalnej możliwej wartości zasilania sieci, która jest określona przez zdolność przepustową sieci, którą zasila oraz/albo przez zdolność przepustową urządzenia przesyłowego albo transformatora, za pomocą których energia wytworzona w instalacjach wiatrowych jest przekazywana do sieci, przy czym ograniczenie przeprowadza się dla każdej oddzielnie regulowanej sekcji farmy wiatrowej, ponadto na podstawie wartości aktualnie dostępnej mocy, którą to wartość uzyskuje się z danych instalacji wiatrowej oraz na podstawie parametr ów wiatru, oblicza się różnic ę pomiędzy aktualnie dostępną mocą, która mogłaby być dostarczona, ale została zredukowana, a mocą dostarczoną, tworząc wirtualny miernik prądu.
- 2Sposób według zastrz. 1, znamienny tym, że wzrost albo redukcję mocy w farmie wiatrowej ogranicza się do wartości pomiędzy 5 a 15%, korzystnie 10% mocy przyłącza do sieci farmy wiatrowej na minutę.
- 3Sposób według zastrz. 1, znamienny tym, że instalacjom wiatrowym, które są jako pierwsze wystawione na wiatr wewnątrz farmy wiatrowej ogranicza się moc w mniejszym stopniu, niż instalacjom wiatrowym, które w linii wiatru znajdują się z tyłu wymienionych instalacji wiatrowych.
- 4Sposób według zastrz. 1, znamienny tym, że gdy częstotliwość sieci przekracza wartość zadaną lub spada poniżej wartości zadanej o określoną wartość, korzystnie 2% wartości zadanej nie oddaje się mocy do sieci.
- 5Sposób według zastrz. 1, znamienny tym, że dławienie mocy przeprowadza się w co najmniej jednej albo więcej instalacji wiatrowych farmy wiatrowej albo we wszystkich instalacjach wiatrowych farmy wiatrowej, gdy osiągnięta zostaje maksymalna wartość mocy zasilającej sieć.
- 6Sposób według zastrz. 5, znamienny tym, że dławienie mocy przeprowadza się przy tej samej wartości dławienia dla wszystkich instalacji wiatrowych albo przy różnej wartości dławienia.
- 7Sposób według zastrz. 5, znamienny tym, że jeżeli napięcie w sieci zasilającej spada poniżej wartości znamionowej, odłącza się farmę wiatrową od sieci w bardzo krótkim czasie.
Independent claims7
106 paragraphs in 5 sections, as filed
Description of the invention
The invention relates to a method of operating a wind farm. A wind farm comprises at least one wind installation having an electric generator driven by a rotor and supplying electricity to the electricity grid, and in particular to consumers connected to it.
Initially, wind installations (wind farms) were built as single devices and only in recent years, due to administrative and construction regulations, wind installations are installed in wind farms. The smallest unit of a wind farm therefore comprises a system of at least two wind farms, but usually many more. As an example, we can mention the wind farm called Holtriem (East Frisia), where more than 50 wind installations have been installed in a combined system. It is expected that in the coming years the number of units as well as the installed capacity of wind farms will increase significantly. In most cases, the potential of wind installations is greatest in regions with low-short-circuit power grids and low population density. It is there that the technical limits for connecting wind installations are quickly achieved by wind installations, as a result of which it is no longer possible to install further wind installations in such places.
A conventional wind farm is connected, for example, to a 50 MW transformer, so its total power may be up to 50 MW, i.e. 50 installations, each with 1 MW of nominal power.
The wind farms are not continuously operating at their rated operating point and therefore the entire wind farm does not continuously reach the maximum power values. If the rated power of the wind farm corresponds to the maximum value of all possible feed-in power, it means that the wind farm is not set for optimal use.
In the description of the patent application PCT / EP00 / 06493 (WO0125630 A1) a method of operating a wind farm is presented, according to which the total output power of the wind farm is greater than the maximum possible power of the grid feed. Applying this solution to the example above requires increasing the power to a value in excess of 50 MW, for example 53 MW. At wind speeds high enough to reach the power cap of 50 MW, the wind farm control system - when all maximum power is exceeded - turns on the control to reduce the power of individual installations or the entire wind farm, so that the output power is constantly under control. This means that at a wind speed above the rated value (wind speed where the power of the plant reaches its rated value), at least one or all of the power plants are running at a (slightly) throttled output (e.g. 940 kW instead of 1 MW).
According to the above-mentioned PCT / EP00 / 06493 description, all components of the power network (network components are, for example, transformers and lines) can be used optimally or they can be load balanced in an optimal way (using them up to the thermal limitation is also a possibility). In this way, the existing wind farm can be better used by installing the maximum possible number of wind farms. Therefore, the number of wind installations is not (so strictly) limited by the existing grid capacity.
According to the cited description, the control of the wind installation has a data input, by means of which the electric power can be set within the range of 0 to 100% (of the rated power). For example, if on this data input the reference power value is 350 kW, then the maximum output power of this wind installation will not exceed the reference value of 350 kW. The reference power value can be any value from 0 to the rated value (for example, from 0 to 1 MW). This data input is used directly for power limitation purposes. It is also possible to regulate the generator output power with a regulator, depending on the grid voltage (wind farm grid or power grid).
Assuming that the wind farm contains 10 wind farms, each of which has a rated output of 600 kW, thanks to the capacitive reactance of the grid components (line capacitance) or the limited reactance of the transformer, it was assumed that the maximum power to be delivered (power limitation) is 5200 kW. It is possible to limit the power of all wind installations to a maximum of 520 kW by means of a reference value (at the input). As a result, the power limitation requirement is always met. Another possibility is not to allow the maximum power to be exceeded as the sum of the power of all installations, while producing the maximum amount of energy (kilowatt hours (operation)).
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In the range of low to moderate wind speeds, it is not uncommon for wind farms to receive a fairly strong gust of wind on the wind farm's favorable side (that is, the side that the wind first encounters in the wind farm). And if all wind installations are simultaneously controlled to reduce their power to their throttled values (for example all down to 520 kW), this generated power is actually achieved by some wind installations situated on the good side of the farm, while other wind installations, which, although "in the shadow of the wind relative to these well positioned wind farms (second and third row), receive less wind and consequently operate with less power for example only 460 kW and do not reach a maximum throttled power of 520 kW. Thus, the entire power output of the wind farm is significantly lower than the allowed limit output of 5200 kW.
In such a case, the regulation of the power of the wind farm according to the cited patent is that the power of the individual wind farms is regulated in such a way as to obtain the maximum possible energy production. Thus, the total electricity capacity of the wind farm increases. Wind farm power control assumes power control in individual wind installations in such a way as not to exceed the maximum allowable connection power, and at the same time to obtain the maximum value of the produced work (kWh).
Management of a wind farm according to the cited patent description allows it to be easily adapted to the situation that has arisen. Thus, for example, it is easy to implement different power throttling of individual installations when a single installation or multiple installations of a wind farm are (must) be removed from the grid when, due to maintenance or other reasons, a single installation or multiple installations have to be temporarily shut down.
In order to control the wind farm or the individual wind installations, it is possible to use a data processing device or a control device connected to the data inputs of the individual installations and which, based on the wind speed data at each of these installations, determine an appropriately favorable power throttling value. for each wind farm or for the entire wind farm.
The discussed description of PCT / EP00 / 06493 includes a drawing, presented herein as: Pos. 1, which is a block diagram of a wind farm control system, and Pos. 2 which shows a wind farm;
Pos. 1 is a block diagram of a wind farm control system with a μΡ microprocessor connected to an inverter (PWR) with which the polyphase AC can supply power to the utility grid. The microprocessor has a power P input, a power factor (cos φ) input as well as a power gradient input (dP / dt).
The inverter device, comprising a rectifier, a DC intermediate circuit and a frequency converter, is connected to the generator of the wind plant and receives therefrom the energy produced by the generator with a variable speed, i.e. depending on the speed of rotation of the wind plant.
The solution in this figure is used to illustrate how the power supplied by the wind turbine can be limited to the maximum possible value of the mains feed.
Pos. 2 shows a wind farm comprising three wind farms 1, 2 and 3, two of which, viewed from the wind direction, two are next to each other and the third is located behind them. Since each of the individual wind installations has a power input for the power setting of the respective installation (Fig. 1), the power level of an individual wind installation can be set to the desired value by means of a data processing device with which the entire wind farm is controlled. In fig. The 2 advantages of positioning wind farms are those that the wind encounters first, i.e. plants 1 and 2.
In the case of a low-power power grid (island), if a relatively large consumer is disconnected from the electrical grid, the frequency increases very quickly (impact). Drives such as diesel engines, water wheels and the like take some time to lower their power (mechanical and electrical). During this time, these generators produce more energy than they take from the electricity grid. This energy is then used to speed up the generators. This means that the speed of rotation and therefore the frequency of the grid increases.
However, many electrical devices, such as computers, servomotors and the like, that are connected to the utility grid, are not designed to operate on fluctuating or rapidly changing frequency networks, which can damage these electrical devices to their destruction.
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The Polish patent application no. P.358384 (which is based on the international application PCT / EP / 003705, publication no. WO01 / 86143 A1) deals with the elimination of problems related to frequency and voltage fluctuations at a given point of the network. Frequency stability is achieved in that the power supplied to the grid by the wind farm is regulated or set depending on the frequency of the power grid, the power of the wind power plant is reduced when the grid frequency is higher or lower, preferably by about 3%, and more preferably 6% from its set point. The state of the art according to this patent specification is illustrated in the drawings in which:
Pos. 3 is a graph of frequency / power versus time for a wind farm;
Pos. 4 is a side view of the wind power plant;
Pos. 5 is a block diagram of a microprocessor controlled wind turbine inverter;
Pos. 6 shows a wind farm control device;
Pos. 7 shows the connection of the wind farm to the electricity grid;
Pos. 8 shows an alternative arrangement of Fig. 13;
When wind power installations operate with grids of such low power, their (mechanical and) electrical power is controlled depending on the increase in grid frequency. This is to prevent a further increase in the grid frequency or to achieve a reduction in the grid frequency.
Pos. 3 illustrates the need to reduce the output power P of a wind farm (wind farm) depending on the grid frequency f. In this case, the value of 100% corresponds to the reference or target frequency (50 Hz, 60 Hz) of the electrical network. The values of 100.6% or 102% correspond to the higher values of the frequency f of the network.
The electric power of the wind farm (or wind farm) is not yet reduced, for example when the frequency increases by 0.6% (i.e. up to 100.6%). If the grid frequency continues to increase, the electricity capacity of the wind turbine is reduced. In the illustrated example, the electrical power of the wind power plant is reduced to zero when the grid frequency increases to 102%.
Pos. 5 shows an embodiment of a wind installation that meets these requirements. This wind turbine has adjustable rotor blades (blade angle adjustment) so that the mechanical power of the wind turbine can be reduced. For example, if the angle of attack of the rotor blades is set in dependence on the wind, the force of the rotor blades can be reduced to the required value. The alternating current from a generator (not shown) connected to the rotor which is provided with rotor blades is rectified with a rectifier 2 and smoothed with a capacitor 3. The inverter 4 converts the direct current into alternating current which is supplied to the grid L1, L2, L3. The frequency of this output current is determined by the network. A control device 5 comprising a microprocessor measures the mains frequency and controls the power switches of the frequency converter such that the output frequency corresponds to the mains voltage (mains frequency). If - as described above - the grid frequency increases, the electric power is decreased as shown in Fig. 3.
Shown schematically in Fig. 5, the rotor 4 of the wind plant is coupled to a generator G, which supplies electric power depending on the wind speed, and therefore on the wind power. The alternating current produced by the generator G is first rectified by a frequency converter and then converted into alternating current with a frequency corresponding to the mains frequency. The grid voltage at the grid feed-in point is determined by the grid frequency detector. As soon as the grid frequency exceeds the set value - see pos. 3 - the output electrical power is reduced to counteract the increase in network frequency. Thus, by means of the control device, the frequency of the network is adjusted to the required value or at least a further increase in frequency is prevented.
This method of controlling the power supplied by the wind installation allows for avoiding or significantly reducing fluctuations in the grid frequency.
Pos. 7 shows the connection of the wind installation to the electricity grid, where the electricity generated by the wind installation is supplied to the grid at the feed-in point. Numerous recipients are connected to the network, presented in the example schematically in the form of houses.
Pos. 8 shows the more important components of the control and regulation device in a slightly different way than Fig. 5. The control system has a rectifier in which the alternating current generated in the generator is rectified. An inverter connected to a rectifier converts the direct current, initially converted in the intermediate circuit, into the alternating current that feeds the grid in the form of a three-phase current
PL 212 098 B1 via the lines L1, L2 and L3. The inverter is controlled by a microprocessor, which is part of the entire control device. For this purpose, the microprocessor is connected to the inverter. The input parameters for the voltage control with which the available electric power of the wind installation 2 feeds the network are the instantaneous value of the network voltage, the network frequency f, the electric power P of the generator, the power factor cos φ, as well as the power gradient dP / dt. In the microprocessor, regulation of the supply voltage with a given network frequency is performed.
In known wind power plants producing electricity, the generator works in parallel with the energy consumer, often the power grid. During operation of a wind plant, the active electrical power produced by the generator can vary depending on the prevailing winds. As a result, the grid voltage (magnitude and phase) may also vary, for example at the feed point, depending on the currently prevailing wind speed. The same also applies to the supply current.
However, in a situation requiring the supply of electricity produced for the utility grid, for example the public utility grid, fluctuations in the grid voltage may occur. However, in the interest of the reliable operation of the connected consumers, such fluctuations are only allowed to a narrow extent.
Relatively large deviations from the reference value regarding the mains voltage, in particular for medium voltages, can be compensated for, for example, by switching on switching devices such as regulating transformers, which are triggered when the value exceeds or falls below a predetermined limit value. In this way, within the specified tolerance limits, the grid voltage is kept substantially constant.
According to the invention, a method for operating a wind farm comprising a plurality of wind farms connected to a power grid which it supplies with the electricity generated by the wind farm and the wind farm and / or at least one of its wind farms has a control input by means of which the electric power of the wind farm or one or more individual wind farms can be set to deliver 0 and 100% of the available power, in particular the rated power, the set point being set by means of a data processing device connected to the control input with which the set point value is set in the range from 0 to 100% depending on the power that the entire farm supplies to the utility grid on its own the power output, and the operator (power company) of the energy supply network to which the wind farm is connected, sets the power produced in the wind farm via the control input, characterized in that it comprises a step in which the power supplied by the wind farms is limited to the maximum possible feed-in value, which is determined by the capacity of the network it is feeding and / or by the capacity of capacity of a transmission device or transformer through which the energy generated in wind installations is transferred to the grid, the limitation is carried out for each separately regulated section of the wind farm, moreover, on the basis of the value of the currently available power, the value of which is obtained from the wind plant data and the wind parameters, the difference between the currently available power that could be delivered is calculated, but was reduced and the power delivered, creating a virtual current meter.
The increase or reduction of power in the wind farm is preferably limited to between 5 and 15%, preferably 10% of the connection power to the wind farm grid per minute.
The wind installations which are first exposed to the wind inside the wind farm are limited in their capacity preferably to a lesser extent than those of the wind installations which are located at the rear of said wind farms in the wind line.
Preferably, when the grid frequency exceeds the setpoint or falls below the setpoint by a predetermined amount, preferably 2% of the setpoint is not fed into the grid.
Power throttling is preferably performed in at least one or more wind farms of the wind farm, or in all wind farms of the wind farm, when the maximum value of feed-in power is reached. The power throttling is more preferably performed with the same throttling value in all wind installations or with a different throttling value. If the voltage in the supply network drops below the rated value, it is best to disconnect the wind farm from the grid in a very short time.
A wind farm or wind farm, even with fluctuations in the supplied active power, is able, compared to the situation when the power grid is without wind or wind installations,
To reduce or at least not to significantly increase the undesirable voltage fluctuations at a given point in the network.
By changing the phase angle (the electric power generated by the wind power installation or wind installations depending on the voltage at the customer or in the network, depending on the measurements in the network, it is possible to reduce at least one voltage in the network or at least prevent a significant increase in network point. In this way, it is possible to compensate for undesirable voltage fluctuations that arise as a result of changes in the active power supplied by the wind power installation or wind installations and / or the power drawn from the grid by the consumers.
It is particularly advantageous to alter the phase angle such that the voltage at at least one predetermined point in the network remains substantially constant. In such a case, in order to obtain the required control parameter, the voltage is measured in at least one point of the network. In particular, this point may not be a power point. Measurements of the voltage value and the appropriate change of the phase angle of the electric power supplied by the wind power installation or wind power installations allows to obtain a quickly responsive and effective control system.
In a particularly preferred embodiment, the values to be given for setting the phase angle are derived from the given parameters. These parameters may advantageously be provided in the form of a table in which the preset families of characteristics are presented in the form of discrete values which allow the derivation of the phase angle setting.
In an advantageous development of the invention, the control system can directly or indirectly cause that when a predetermined limit value of voltage fluctuations is exceeded, it is brought back to the tolerance range by actuating a switching device, for example a control transformer, in the network. Simultaneously or in addition, the phase angle is set over a predetermined period to a constant value - preferably an average value, for example zero, in order to be able to compensate for the subsequent voltage fluctuations, again by means of an appropriate change of the phase angle.
According to the invention, the corresponding steps of measuring the voltage and adjusting the phase angle are performed separately in the electrically separated network sections in order to control each section so that the voltage in each of these sections remains substantially constant.
The control device preferably has a microprocessor as in this way digital control is possible.
Advantageous development of wind farms provides suitable devices enabling the application of the method according to the invention and voltage measurements for each separately regulated part of the wind farm, so that electrically separated grid sections can also be separately regulated such that the voltage in each of these grid sections remains essentially constant.
The subject of the invention in the exemplary embodiments is shown in the drawing, in which:
Fig. 1 shows a simplified representation of a wind power plant feeding the grid,
Fig. 2 shows a control device designed to work with a wind power plant;
Fig. 3 shows the relationship between the mains voltage and the phase angle;
Fig. 4 shows the main components of the adjusting device shown in Fig. 2 and
Fig. 5 schematically shows a control system for a plurality of wind power plants.
The wind power plant 2 shown schematically in Fig. 1 has a rotor 4 and is connected to a grid 6 which may for example be a public main grid. A plurality of consumers 8 are connected to the grid. An electric generator (not shown in Fig. 1) of the wind power plant 2 is connected to a control device 10 which initially rectifies the alternating current produced in the generator and then converts it into an alternating current whose frequency corresponds to the grid frequency.
A voltage measuring device can be provided at each measuring point 22 of the network 6, measures (in addition to the phase) in particular the value of the network voltage and returns this measured value to the control device 10 as the corresponding control parameter.
Fig. 2 shows a control device according to the invention. The schematically illustrated rotor 4 is coupled to a generator 12 which produces an electrical power which may depend on the wind speed. The alternating current produced in the generator 12 may first be rectified and then converted into an alternating current whose frequency corresponds to the frequency of the grid.
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The grid voltage is measured at measuring point 22 of grid 6 with a voltage measuring device (not shown). Depending on the value of the measured mains voltage - possibly by means of a microprocessor shown in Fig. 4 - the optimal phase angle is calculated. The network voltage U is then regulated by a control device to a predetermined value Uref.
The electric power supplied by the generator 12 to the network 6 is regulated by changing the phase angle.
Fig. 3 shows the relationship between the line voltage and the phase angle. If the voltage deviates from its setpoint Uref, located between the voltage values Umin and Umax, then according to the characteristic curve of the diagram, the phase angle is changed in such a way that, depending on the sign of the deflection, either inductive or capacitive reactive power is supplied to the network in to stabilize the voltage at the voltage measuring point (measuring point 22 in Fig. 1).
Fig. 4 shows the main components of the control device 10 of Fig. 21. The control device 10 has a rectifier 16 in which the alternating current generated in the generator is rectified. An inverter 18 connected to a rectifier 16 converts the pre-rectified direct current into alternating current which feeds the network 6 in the form of three-phase alternating current via lines L1, L2 and L3.
The inverter 18 is controlled by a microprocessor 20 which is part of the entire regulating device. For this purpose, the microprocessor 20 is connected to the inverter 18. The input quantities to the microprocessor 20 are the actual value of the mains voltage U, the electric power P of the generator, the set point of the mains voltage U<sub>ref</sub> and the power gradient dP / dt. According to the invention, the variation of the power to be delivered is performed in the microprocessor 20.
Fig. 5 shows two wind farms 2 as an example of a wind farm. The control unit 10 is connected to each of the wind installations 2 which of course can also symbolize multiple wind installations. The control unit 10 measures the voltage at the preset measurement points 22, 27 of the network 6, 7 and transmits this data via lines 25, 26 to the appropriately assigned control devices 10.
The sections 6, 7 of the network can be connected to each other or separated by means of a switching device 23. A switching device 24 is provided in parallel with the switching device 23, which makes it possible to connect or disconnect two control devices 10 according to the state of the switching device 23.
Thus, if the two sections 6, 7 of the grid are connected to each other, then the two control devices 10 are also connected to each other, so that the entire grid can be considered as one whole and is fed by the entire wind farm as a whole, the wind farm being uniformly regulated depending on the voltage at test points 22, 27.
On the other hand, if the two sections 6, 7 of the grid are separated by a disconnecting device 23, the control devices 10 are also separated from each other such that a part of the wind farm is monitored at the measurement point 22 by a line 25 and the corresponding part of the wind farm can be suitably adjustable from control device 10, and the second network section 7 is monitored at point 27 by line 26 and appropriately adjusted by control device 10, to stabilize the voltage in section 7 of the network.
The division of the network need not be limited to two sections. It can go further by assigning one installation to one network section.
The central control of the wind farm according to the invention provides that the wind farm not only feeds energy to the supply grid, but can at the same time be controlled in such a way that it supports the grid, preferably with the aid of a public grid operator (electric utility company). In principle, when in this specification reference is made to a wind farm, this also applies to individual wind installations, and when it is mentioned a plurality of wind installations it is not always the case for a wind farm.
In order to centrally control the wind farm according to the invention, the public utility grid operator not only has control access via a suitable control line (bus system) to the wind farm / wind farms, but also receives wind farm / wind farm data such as e.g. measured wind parameters, data on the condition of the wind farm and also, for example, data on the available power (current power (active power)) of the wind farm.
Such centralized control may also mean, for example, that in certain circumstances the wind farm has been completely disconnected from the grid, for example in a situation where the operator's rules for connection to the wind farm grid cannot be complied with.
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For example, if the grid voltage drops below a predetermined value, for example to a value between 70 and 90% of the grid voltage, the wind farm must be disconnected from the grid within a certain time, for example two to six seconds.
It is important that the change in power dP of the wind farm is not only caused by the wind, but can also change in the given time intervals. This power parameter is also called the power gradient and determines by how many percent a given available power can change over a certain period of time (for example per minute). For example, it can be provided that the power gradient of the wind farm is 5 to 15%, preferably 10%, of the grid connection power per minute.
The control of the wind farm can take place, for example, in all wind installations or in the farm simultaneously or evenly, increasing the power supply with a predetermined power gradient. Of course, alternatively it is possible to assume that for a wind farm with e.g. 10 to 20 installations, first one or two installations (in the correct order relative to the power gradient value) start feeding the grid at full power and then depending on their assumed power gradients, further installations are switched on within the assumed time, until all available wind farm capacities can start feeding the grid.
Another aspect of the control of the wind farm according to the invention is the provision of a reserve capacity of, for example, 10% of the wind farm's currently available power, or a predetermined value of, for example, 500 kW and 1 MW or more per wind farm. This reserve capacity should not be confused with a wind farm capacity that exceeds the grid connection capacity of the wind farm. This reserve power definitely relates to the reserve power (both active and reactive power) which does not exceed the range of the grid connection power. This standby capacity is recommended by the utility grid operator. This means that when the wind is sufficient from the point of view of the wind farm to supply the grid with the connection power, the energy company may decide, by recommendation being an intervention in the control of the wind farm, that all theoretically possible available capacity will not be used and some of it will remain in reserve character. In particular, this power reserve applies when, due to unexpected power failure in the power plant (at other points in the grid feed), the grid can be stabilized by requesting the inclusion of the corresponding reserve power.
Thus, with the above-described central control of the wind farm, the power supplied to the grid is normally lower than the obtainable power of the wind farm (maximum available power) and depends on the power demand in the grid.
Thus, the above-described power control procedure can be used by the grid operator who also needs the above-described data, such as wind speed, the condition of the wind farm installations (number of installations currently in operation, number of inoperative or damaged installations) and preferably also the maximum value of the possible power supply. open. Moreover, with regard to the maximum value of the possible active power supply, it is essential that it only needs to be presented in the form of data if it cannot be determined from the wind speed and the condition of the installation.
The normal bus system as well as the standard bus system can be used to control the wind farm as well as to provide data to the utility plant. There are standard interfaces for such a standard bus system, for example a Profibus system, so that central control of a wind farm can also be realized with the appropriate standard control commands.
Additionally, it can also be established that a wind farm with a designed capacity, for example a total output capacity greater than 50 MW, is considered a large-capacity power plant and therefore must meet the conditions required for such a plant. It is therefore established that the wind farm is regulated so that the switching value (switching capacity) is not exceeded. It is important that there are no undesirable effects of grid reverse effects when switching off / on in the wind farm. For example, when switching on / off the wind farm, the current should not be higher than the set value compared to the rated power corresponding to the switching capacity. This value may be in the range of 1.0 and 1.4, for example.
If the frequency of the public utility grid increases, then - as already described - it is important that, from reaching a given frequency, e.g. from 50.25 Hz (at a nominal frequency of 50 Hz), the supplied active power of the wind farm is automatically reduced until the grid frequency stabilizes again at value stated above.
Thus, it must always be possible for the wind farm to operate at a lower feed-in power level in order to be able to meet the grid demands. This wind farm power regulation also means
That the power supply (in particular active power) can be reduced to any given value under any operating conditions and from any point.
Thus, it is possible, for example, to limit the feed-in power below the available feed-in power, if the operational reliability of the system is endangered, there are bottlenecks, or if there is a risk of overload in upstream networks, there is a risk of island network formation, static or dynamic stability is endangered. , an increase in frequency may jeopardize the entire grid system and, for example, remedial actions or other shutdowns are to be undertaken by the utility.
In addition to the above-described and demand-driven active power supply, it should also be possible to supply reactive power, which can be set at the request of the utility company in terms of both inductive and capacitive power, i.e. under-excitation and overexcitation, with corresponding their values can be asked by the utility company.
The reactive power setpoints can be set variable, with the setting of the power factor (cos φ) or voltage setpoint taking place at network connection nodes. It is also possible to define a fixed reference value.
As already described above, the power supply is reduced and / or the wind farm is completely disconnected from the grid if the grid frequency value exceeds or is below a certain level. Thus, for example, a wind farm may be excluded from the grid when grid frequency values exceed or fall below certain levels. For example, a wind farm may be disconnected from the grid when the grid frequency drops below 48 Hz (at a grid frequency of 50 Hz) or increases to 51 or 52 Hz. With values below the predetermined range, it is still possible to stay within the limit range if only one part of the current available capacity is fed into the grid, for example 80 to 95% of the current available capacity.
For example, if the grid voltage fell below the assumed value, the situation would be the same as for the frequency. In other words, when the voltage drops below or exceeds the assumed grid voltage by a certain value, the power supply is reduced first, and when the grid voltage drops below or exceeds the given value limit, the wind installations are completely disconnected from the grid or at least the grid feed power is set to zero. .
It is therefore determined that when a certain grid voltage and / or grid frequency is reached, an attempt is made to shut down the wind farm without supplying power that has already been reduced previously.
However, this also means that with given frequency or voltage deviations, which are within the given range around the grid frequency / voltage, it is not permissible to automatically disconnect the wind farm from the grid.
For grid protection purposes, it can also be established that the tripping time when the voltage is exceeded is much shorter (for example between 50 and 200 milliseconds) than for voltage reduction protection (disconnection time greater than 1 second, preferably 2 and 6 seconds) . Thus, the turn-off time, when the higher or lower frequency value exceeds or falls below a predetermined value, still of the allowable limit is approximately in the range of the turn-off time when the voltage exceeds the predetermined value.
In the event of a grid failure, for example in the event of a short circuit, the wind farm does not always automatically disconnect immediately, but the wind farm can also be controlled such that, depending on its connection to the grid, it will still feed the grid with a share of the short circuit power with its apparent power at to be able to provide some support to the network. This means that the wind farm is to deliver the highest possible apparent current (apparent power) for at least a certain duration of the fault, but for a maximum of a few seconds, which corresponds, for example, to one or 1.5 times the switching capacity current.
The above-described operation can be made dependent on the rated voltage level, for example, if the voltage exceeds a predetermined value, for example 50 kV.
In order that the described switch-off procedure can take place in good time, a protective relay (distance protection) can, for example, be installed in the interconnecting node.
Means should also be provided which, when starting the wind farm, synchronize the grid voltage and the wind farm voltage, because when the wind farm is restarted, the asynchronous voltage severely disrupts the grid and may cause its shutdown.
PL 212 098 B1
Power throttling below the wind farm's distribution capacity can be done in various ways.
Thus, for example, the power may be reduced in total at the individual plants, so that the total available power of the wind farm assumes the desired reduced power value. An alternative to this may be to assume that only individual installations are reduced in terms of their feed-in power, so that the total feed-in power of the wind farm again takes the desired value.
Thus, it is determined that, for example, a given available power from the wind farm is placed in intermediate stores, so-called load stores (resistors) or other energy stores, or is converted into another type of energy, so that the value of the wind farm's feed takes on the desired value.
Power output reduction can also be achieved by a procedure in which one or the concerned wind farms are completely removed from the grid so that the total power of the wind farm (in particular its active power) can be set to the desired value and / or below the desired value. values.
For the transmission of wind farm data (wind parameters, state data, power data, etc.) or for the control of the wind farm, a wireless communication arrangement can also be established so that control data or information data can be wirelessly transmitted and processed.
In the case of the above-mentioned wind farm power throttling, the value that can be available as the maximum energy is determined and then also the amount of energy fed to the grid is determined, the difference between these values being the result of the wind farm control by the utility company and on its basis, you can calculate the value of the compensation to be reimbursed if necessary.
As described above, not only the power plant that operates the power grid can limit the output power of the wind farm or individual wind installations, having access to the control line for many reasons (grid protection, servo power), but also the operator of the public power grid can obtain data relating to the status of the wind farm, for example maximum available power, wind speed and so on. When the power is limited to a value below the current available capacity, the wind farm or individual wind farms are not used optimally, leading to power losses on the part of the wind farm operator. Thus, according to the invention, a virtual current meter is provided which determines the difference between the available power of the wind power plant, i.e. the power that the wind power plant could have fed the grid, had this power not been limited by the intervention of the power utility in the control system, and the power actually fed into the grid. Such a "virtual current meter" may, on the one hand, determine the available power on the basis of the wind speed, and when, at the same time, the power plant or anyone else limits the output power of individual wind installations or the entire wind farm to a value below the available power, then it is possible to determine (calculate) the amount of energy that is not fed into the grid. This virtual current meter enables the plant operator to obtain a discount for "virtual current", that is to say, current which is not fed into the grid due to intervention in the power control system. This "virtual current meter" can be installed both by the wind farm operator in the wind farms themselves, by the utility company and also by the wind farm producer.
The term wind farm used in this application is here synonymous with the term wind farm. The various aspects of the invention described in this application may be implemented together in wind farms or in their control itself.
Contents5
54 members in 19 offices
Priority claims1
| Document | Office | Kind | Date |
|---|---|---|---|
| 10148225 | Germany | A |
Members54
| Document | Office | Kind | |
|---|---|---|---|
| CA2460724A1 | Canada | A1 | |
| WO03030329A1 | World Intellectual Property Organization (WIPO) | A1 | |
| NO20041854L | Norway | L | |
| KR20040037185A | Republic of Korea | A | |
| EP1433238A1 | European Patent Office (EPO) | A1 | |
| MXPA04002715A | Mexico | A | |
| ZA200402379B | South Africa | B | |
| AR036656A1 | Argentina | A1 | |
| BR0212820A | Brazil | A | |
| CN1559097A | China | A | |
| JP2005505223A | Japan | A | |
| PL367490A1 | Poland | A1 | |
| US2005042098A1 | United States of America | A1 | |
| US2006142899A1 | United States of America | A1 | |
| AU2002340927B2 | Australia | B2 | |
| US2007090651A1 | United States of America | A1 | |
| NZ531991A | New Zealand | A | |
| KR100742990B1 | Republic of Korea | B1 | |
| US7392114B2 | United States of America | B2 | |
| JP2009011154A | Japan | A | |
| EP2113980A2 | European Patent Office (EPO) | A2 | |
| CN100566069C | China | C | |
| US7638893B2 | United States of America | B2 | |
| US2010276931A1 | United States of America | A1 | |
| US7830029B2 | United States of America | B2 | |
| EP2275674A2 | European Patent Office (EPO) | A2 | |
| PL393264A1 | Poland | A1 | |
| JP4881349B2 | Japan | B2 | |
| JP2012041931A | Japan | A | |
| PL212009B1 | Poland | B1 | |
| PL212098B1This record | Poland | B1 | |
| US8301313B2 | United States of America | B2 | |
| CA2460724C | Canada | C | |
| EP2113980A3 | European Patent Office (EPO) | A3 | |
| JP2013102684A | Japan | A | |
| JP5216181B2 | Japan | B2 | |
| JP5463333B2 | Japan | B2 | |
| EP2275674A3 | European Patent Office (EPO) | A3 | |
| EP2113980B1 | European Patent Office (EPO) | B1 | |
| ES2568499T3 | Spain | T3 | |
| DK2113980T3 | Denmark | T3 | |
| EP3032685A1 | European Patent Office (EPO) | A1 | |
| EP2275674B1 | European Patent Office (EPO) | B1 | |
| CY1117353T1 | Cyprus | T1 | |
| EP1433238B1 | European Patent Office (EPO) | B1 | |
| PT2275674T | Portugal | T | |
| DK2275674T3 | Denmark | T3 | |
| ES2627818T3 | Spain | T3 | |
| DK1433238T3 | Denmark | T3 | |
| PT1433238T | Portugal | T | |
| ES2634838T3 | Spain | T3 | |
| CY1118917T1 | Cyprus | T1 | |
| EP1433238B2 | European Patent Office (EPO) | B2 | |
| EP2275674B2 | European Patent Office (EPO) | B2 |
Numbers
- Publication
- 212098
- Application
- 39326402
Titles2
- English
- Method for operating a wind farm and wind farm implementing this method
- Polish
- Sposób eksploatacji farmy wiatrowej
Classification
- CPC, 16
- F03D7/048
- H02J3/38
- F03D7/0272
- F03D7/0284
- F05B2270/1033
- F05B2270/304
- F05B2270/335
- F05B2270/337
- Y02B10/30
- F03D9/255
- F03D9/257
- H02J3/381
- Y02E10/76
- Y02E10/72
- H02J3/40
- H02J2101/28
- IPC, 7
- F03D7 02
- B63H1 06
- H02J3 38
- F03D7 00
- F03D7 04
- F03D9 00
- H02P9 00