Operating method for a wind park and wind park

[0001] The present invention relates to a method of operating a wind park with a number of wind farms. Furthermore, the invention relates to a wind farm with an electrically excited generator and a wind park with a central park control device.

[0002] The term "wind park" is used here to mean a number of wind farms that are connected to a common grid connection point, irrespective of the spatial arrangement of the individual wind farms relative to each other. That is, also a number of wind farm groups separated from each other in space is considered a wind park if it is connected via a common transformer station to the grid connection point.

[0003] Wind parks have been known for some time in the art. In this type of wind farms, on a larger scale than it is possible in individual installations, the kinetic energy of the wind is converted into electricity. The prerequisite is of course sufficient wind power.

[0004] A wind park comprising a number of installations is, for example, also known from US 6,420,796. In particular, it describes that the electrical power required to run a wind farm after a period of downtime is taken from the electrical buffer assigned to the wind farm.

[0005] From JP 09-060575 (Matsuo Kyoryo), a wind power plant is known, in which electricity is generated using an auxiliary wind power plant to provide the induction power of a wind farm induction machine.

[0006] However, since the wind does not blow continuously, the windless period can be used to carry out operating procedures such as unscrewing the cable or the like. However, since wind farms do not produce electricity during windless periods, they draw the energy needed to carry out these procedures from the grid. However, the grid power consumption limit agreed with the grid operator applies. In addition, the energy consumed from the network is relatively expensive, and the share exceeding the agreed limit is billed by the network operator even more. As a result, depending on the amount of energy consumed from the network, the wind farm operator incurs additional costs that reduce the profit brought by the wind park.

[0007] The object of the present invention is therefore to provide a method for operating a wind farm with a number of wind farms, a wind farm with an electrically excited generator and a wind park with a central park control device where the operating procedures are carried out with limited or reduced power consumption from the network (power consumed).

[0008] This objective was achieved by presenting a wind farm of the type indicated at the outset with the properties given in claim 1. According to the invention, the operating procedures for at least one wind farm are controlled in such a way that the electric power is taken from the network to a predetermined maximum value . By adequately limiting the power consumed from the network (power consumed), it is ensured that the power consumed does not exceed at least the agreed maximum value. In this way, at least significantly higher outlays for power exceeding the maximum value can be avoided.

[0009] In a preferred embodiment of the invention, the procedures for operating wind farms are implemented in at least two groups offset by a definable period of time. By creating groups, it is ensured that the power consumed by the network is constantly consumed only by so many wind farms that the power consumed is as low as possible or at least does not exceed the agreed maximum value.

[0010] In a particularly preferred further embodiment of the method, the first group is formed by one wind farm. This is particularly advantageous when the operating procedure is to start the wind park, for example after the wind has broken again. Instead of drawing the electricity required to switch azimuth, blade angle, control the installation and excite the generator for all installations in a wind park, this is done in relation to one group, which group preferably consists of one wind farm. Thus, this required energy is taken from the grid for only one wind farm.

[0011] As soon as this one wind power plant generates electricity itself, this energy will be used to run further power plants, which in turn will generate electricity, which is then used to run further power plants. By means of such time scheduling for the purpose of starting a wind park, the power required only for starting the first power plant should be taken from the network, while the other wind farm plants can be started using the power already generated in the park. In this way it is not possible to transfer the power generated in the wind park to the network, but you do not need to draw more expensive power from the network.

[0012] According to a preferred further embodiment of the method according to the invention, the power used for the operating procedures is limited to a measurable proportion of the power generated in the wind park. In this way, a wind park can be started on the one hand, and electric power is available on the other, which can be transferred to the network. As a result, you can support a weak network also when starting a wind farm, instead of drawing power from the network to start a wind farm.

[0013] Particularly preferably, the method is designed so that wind farms with the lowest energy demand for a particular operating procedure advantageously implement it. A distinction should be made here between operating procedures to be carried out. If the operating procedure to be carried out is, for example, unscrewing the cables, this procedure, according to this preferred embodiment, is first carried out on the side first by those wind farms with the least twisting. These power plants can carry out this operation quickly enough and are immediately available again for generating electricity. Similarly, changing the nacelle setting when the wind direction changes is first carried out preferably in those power stations where the smallest angle of deviation occurred.

[0014] Various aspects may be considered during the wind farm commissioning procedure. One aspect, for example, is to run wind farms that are furthest windward, that is, they are oriented towards the wind, because these plants are not sheltered by other power plants and therefore can receive most of the wind energy. Another aspect concerns the highest power yield at a given wind speed. Therefore, the power characteristics of the wind farm can be taken into account here, so that with the available wind available, the maximum possible electric power can be generated. Obviously, combinations of these features are also possible, for example taking into account the smallest deviation angle and the largest electrical power.

[0015] For a wind park to be started without power consumption from external sources, it may include a permanently excited wind power plant with a motor-less change in the orientation of the nacelle in the event of a change in wind direction. The possibility of starting without power consumption from external sources means the possibility of starting a wind farm, although from the network, for example as a result of its failure, you can not draw energy. With the use of a constantly induced wind farm, it is therefore possible to start at least one wind farm first, which, according to the proprietary method, generates energy that is used to run subsequent wind farms. In any case, electricity is required to power the control system (s) intended to start up the wind farm (s), even when the jump angle and azimuth position are sufficient to start the wind farm (s), and the generator's remanence is sufficient to arouse.

[0016] Further preferred embodiments of the invention are set out in the dependent claims.

[0017] In the following, an embodiment of the invention will be explained in more detail based on the figures. They show: Fig. 1 shows a wind park to explain the method according to the invention;

Fig. 2 shows a wind park according to the invention.

[0018] Figure 1 shows a wind farm 10 with a number of wind farms. Some of these wind farms are marked with numbers 21-35. In addition, the figure indicates the direction of the wind 15. Based on this figure, the activation of the wind park according to the method of the invention is explained.

[0019] The furthest side on the windward side, i.e. towards the wind, is power plant 21. This power plant can thus obtain maximum energy from the wind. Therefore, first of all, only this wind power plant 21 is started using the power taken from the network for azimuth adjustment, rotor blade adjustment, generator excitation, plant control and similar purposes. The power consumption is around 5 kW, with this value obviously also depending on the type of installation.

[0020] If a wind speed of about 6m / s is taken as a basis, then 80 kW is taken for example. Since this power is the power given off by the wind farm, energy consumption is already included. Therefore, another 16 wind farms can be started using the power given off by this wind farm and so on. It is very clear here that despite the time-delayed start-up, the entire wind farm can be started quite quickly. Thus, the relatively small loss as a result of the "delayed" commissioning of a number of wind farms can be contrasted with high savings in terms of power consumption, which does not have to be paid for.

[0021] Fig. 2 also shows a wind park 10 with a number of wind farms 28-40. In addition, within the wind farm 10 there is also a constantly excited wind power plant with a motorized change in the position of the gondola in the event of a change in wind direction 50. A motorized change in the position of the gondola in the event of a change in wind direction is shown in the form of a weathercock 51. This wind farm 50, with a rising wind, is automatically directed by the weather vane 51 towards the wind and starts generating electricity, because the generator is constantly excited, i.e. it does not require an excitation current.

[0022] Since such induced wind farms are well known in the art, a detailed description of this type of installation is omitted here. In this embodiment, the ENERCON E-12 wind power plant is adopted, which can produce 30 kW of power and at a previously adopted wind speed of about 6 m / s generates about 6 kW, i.e. enough power to at least run another wind power plant in wind park. As such, it can be ensured, as such, that adequate emergency power supply is provided for the minimum required power supply to the plant control device. [0023] According to the above example, a power plant 21 can therefore be started at a power consumption for starting a wind farm of about 5 kW. This at 80 kW would provide sufficient power to run another 15 wind farms in a wind park. In this way, 17 out of 20 wind farms in the wind park will be operating in a short time 10. No electricity from the grid was used, and therefore no costs were incurred, and the wind park could be started despite a power failure and can provide power to the network.

[0024] Since in the event of a network failure, the so-called power system failure, the frequency and voltage must first be reproduced, of course a master device is needed that takes over this function, for example, using a frequency converter.

The (other) wind farms can then be synchronized with the grid and start transferring power. Depending on the needs, this transferred power can be reactive and / or active power.

[0025] The above describes how a particular wind farm can be commissioned with the lowest possible energy consumption from the grid, and the corresponding concept for a single wind farm will be described below.

[0026] If the wind power plant is stationary due to insufficient wind or because of its stopping, for example for service work, electricity is needed to run this wind power plant at least to supply power to the installation control device and / or to move rotor blades to ensure optimal angle of alignment pitch), and / or to position the wind turbine engine room relative to the wind in such a way that the rotor can be optimally driven by the wind, and so on.

[0027] For existing wind farms, as described above, the energy needed to run the wind farm is regularly drawn from the grid. This energy is obtained from the network operator, which however requires high expenditures, and the wind power plant operator has to pay a much higher price for the energy consumed than that obtained by providing the right amount of energy from the network operator.

[0028] The object of the present invention is therefore, in addition to the above description, also to reduce the electricity demand from the network to run a single wind farm, thus reducing the total costs of operating the wind farm.

[0029] To this end, it has been proposed that in the case of one wind farm that has an energy storage in which electricity is stored, in order to start the wind farm first use energy from the energy storage in order to move the machine frame to the correct azimuth position and / or to provide the necessary excitation power for the generator and / or to move the rotor blades to obtain the desired angle of alignment, in particular to activate the device for controlling the installation, and for this purpose to supply electricity.

[0030] As an energy store, for example, an electric energy store can be used, which is often used in wind farms for emergency shutdown of wind farms, for example an electric energy store to provide energy for positioning the rotor blades in case of emergency shutdown. It must be ensured that sufficient energy is left in the energy storage for emergency shutdown.

[0031] Preferably, when starting up the wind farm, to move the machine room, the rotor blades are set in terms of the angle of alignment, in such a way that the rotor is driven and the generator is then energized with excitation energy, so that the wind turbine is able to produce using a generator.

[0032] It is also possible that the electricity generated by the generator alone or in combination with the energy still available in the electric storage is used taking into account the reserve for emergency shutdown in order to move the machine frame to the correct azimuth position.

[0033] Preferably, during the movement of the machine frame, when the rotor is rotating, the rotor blades are moved to a given position in which the rotational movement of the rotor is not inhibited or slightly inhibited [0034] Because the cables at the transition between the nacelle and the wind turbine tower sometimes they have to be unscrewed (because the gondola rotated many times in the same direction around the axis of rotation), and unscrewing is carried out regularly, when the installation is immobilized, with the energy needed for spinning, i.e. for 360 ° azimuth rotation and more, it must again be taken from the network, it is proposed that spinning should take place when the wind speed is greater than the starting speed, preferably, however, less than the nominal speed. Under such conditions, the energy needed for spinning up can be obtained in the wind park itself from individual wind farms, which then supply the power they generate to the installation in which spinning is necessary, which means that you do not need to draw energy from the grid to spin up.

[0035] When the wind speed is, for example, around 5m / s, the energy yield is not very high, but it is enough to regularly obtain the energy needed to rotate the engine room.

[0036] In the case of Enercon wind farms, for example wind farms type E-40 or E-66, for emergency shutdown, electric energy accumulators are used for each rotor blade, type Ultracap (manufacturer: Epcos), with which you can store a relatively large amount of energy, which is regularly enough to ensure not only a one-off emergency shutdown, and with it the adjustment of the rotor blades with the setting of the blades in the flag, but also sufficient additional energy to provide energy for other elements of the power plant, e.g. plant control, azimuth or other devices.

[0037] When wind farms or a wind farm are equipped with a separate energy store, for example a battery, the energy from this battery can also be used to start the installation, or the energy required for this at the outset.

[0038] It is also possible to equip one wind power plant with a small wind turbine rotor which, when starting up the wind power plant, provides the necessary energy in whole or in part, provided that the electricity can be sufficiently provided by another energy storage.

[0039] If own energy reserves were not enough for the needs of commissioning, they are used first, whereby the consumption of electricity from the network takes place only later, as a result of which it is kept to a minimum.

[0040] Finally, during normal operation of a wind power plant, energy from energy storage can be re-supplied from energy sources self-generated by wind farms.

[0041] As far as the present application is concerned, the energy storage can also be its own generator within a wind farm, e.g. a diesel generator, i.e. a generator with which electricity can be generated that does not need to be taken from the grid to run one or more wind farms.

[0042] When a wind turbine is equipped with a small wind turbine rotor, for example one that provides about 250 watts up to 3 kW (this kind of wind turbine rotor can be placed virtually anywhere, for example in a tower, nacelle and others in a wind power plant) , it is easily possible for a wind power plant to be powered by electricity when it is unable to draw energy from the grid for various reasons. Since wind farms are often constantly reliant on electricity consumption, for example to operate warning lights (flashing light) and / or to operate control and regulation components, this necessary energy (also to charge the existing energy store) can be provided using a small wind turbine. In addition, this small wind turbine rotor, as already described, can also be used to supply all or part of the electricity to run a wind farm. This can also be done, for example, when moving the rotor blades also in such a way that not all rotor blades are adjusted simultaneously, but instead only one rotor blade first, so that the installation itself begins to rotate with sufficient wind, which means that the produced then the energy of the wind power plant is also sufficient afterwards to move the other rotor blades to the desired angle.

[0043] A further aspect of the invention is that not only the energy generated by a single wind power plant is used to run another or more wind power plant, for example to provide energy so that the correct azimuth angle can be taken, but then , when there is a windless period, i.e. at low wind speed, which may drop to 0, and wind farms in the wind park are gradually turned off, this also takes place in accordance with the invention in such a way that the wind farms in the wind park are set in different directions. This can be done, on the one hand, in such a way that a control system in the power plant is used so that, shortly before the final shutdown, the installation turns in a predetermined or determinable direction, or in such a way that through such installations, which are still spinning and generate little electricity at the same time, electricity is used to drive the azimuth drive of other installations, so that these installations have a setting, which is different from others.

[0044] When the windless conditions continue and the wind stops or blows at such a low speed that no power plant produces electricity anymore, different power plants or different groups of power plants have different wind conditions.

[0045] When a stronger wind appears that blows at a speed exceeding the value of the activation speed, part of the plant is already basically correctly aligned with the wind and can immediately start generating energy without having to switch azimuth in such power plants. These power plants can advantageously produce energy that is used to first correctly shift the azimuth of other installations.

[0046] Of course, it is possible that not only each individual installation takes a different direction, but it can also be done in groups, whereby a number of selected power plants are directed almost in the same direction when in windless conditions the wind speed is below the value of the activation speed .

In any case, the previously described solution with different orientation relative to the wind direction of various installations in the event of windless conditions is advantageous in that it is thus ensured that with increasing wind it is possible to start at least one wind farm in a wind park without the need for significant azimuth adjustment.

[0048] A variant of the previously described solution consists in the fact that those wind farms, which in the event of windless conditions are turned off in the first place, take the azimuth direction, which is as far as possible against the current wind direction, which means that in still wind conditions The wind farms that turn off last remain in the direction from which the wind was blowing recently.

[0049] A further variant is that there are specific preferred directions in which the installations are positioned when windless conditions occur. This preferred direction can be, for example, the main wind direction, which means that with increasing wind, i.e. after the windless period, there is quite a high probability that the wind will blow from the main wind direction, which means that a very large number of wind farms do not need rearrange completely when it comes to azimuth.

[0050] The wind park manager or the corresponding computer containing a program that ensures that individual installations take a different azimuth direction depending on the current wind direction is responsible for the different azimuth direction of wind farms in the event of windless conditions. This can be done in such a way that no azimuth direction is set, but specific preferred directions, for example four main directions: north, east, south, west. For example, installations in the wind park located on the west side can be directed to the west, installations located on the north side of the wind park to the north, installations located on the east side of the wind park to the east, and installations located on the south side of the wind park to the south. Obviously, intermediate characters are also possible between settings relative to the direction of the wind, such as northwest, southwest and others.

[0051] Thus, there is a nearly 100% probability that when the wind rises again to reach a wind speed above the activation speed, the specific installations are directly exposed to the wind and are not on the leeward side of any other installations. In this way, the re-inclusion of all other installations is also accelerated.

[0052] For the purpose of azimuth switching, not only the azimuth drive should be used, but it can also be done in such a way that individual rotor blades of a given installation are asynchronously adjusted relative to others. For example, when 2 out of 3 rotor blades are in the flag position and one rotor blade is positioned to the maximum extent against the wind, by adjusting this rotor blade accordingly, depending on where it is currently located, for example in the hourly position 9.00 or 3.00, you can set the azimuth without the need for an azimuth drive, or it supports the appropriate azimuth setting, so that maximum electricity is not required for the conversion.

Aloys Wobben

Proxy:

EP 1 623 114