Wind power station

[0001] At the planning and installation stage of wind farms, the expected unfavorable optical effect of the wind farm in relation to the surrounding environment, having an impact on obtaining the permit, plays an increasingly important role. For example, if the wind farm is located near a residential building, when the sun is unfavorable, it is possible that the wind farm or its rotor will be between the sun and the residential building. When the sunlight is not disturbed by clouds, the rotating rotor constantly casts a shadow on the land property. The shadow cast by the wind farm on the neighboring area by its inhabitants is often perceived as very disturbing. Even when the wind farm meets the conditions stated in the permit, it is not always guaranteed that there will be no undesirable shading.

[⁰⁰⁰2] Z ^pat^blikACJ^and D^{E 199} 28 ⁰⁴8 known as^t wind farm, in which the power plant shuts down in the case of a specific position of the sun, and thus a specific shading.

[⁰⁰⁰3] ^{From p}at^blikACJ^{and DE 199 29 970} AND¹ known jes^t a way of shading regulation, according to which light intensity is recorded and on this basis it is derived whether shading can occur at all.

[0004] However, sufficient light intensity is only one condition that must be met for shading to occur. For example, transparent air is another condition. In foggy conditions of visibility, the air acts as a dispersion medium, as a result of which, despite the high intensity of light, the shading is only slightly or not at all. Controlling a wind farm using the light intensity parameter can then lead to its shutdown, although there is no shading.

[0005] The object of the present invention is to provide a wind power plant that overcomes the above drawbacks.

[0006] This task is solved according to the invention by providing a wind power plant as described in claim 1. Preferred further embodiments are described in the dependent claims.

[0007] The basis of the invention is the belief that shading can only occur at a specific position of the sun and under certain light conditions or cloud conditions when there is direct sunlight at high light intensity. However, since cloudiness cannot be measured directly, and at the same time it can lead to scattering of light, which is not accompanied by significant shading, a simply recorded difference in brightness between light and shadow is used. When the difference value remains below the set value, there is no noticeable shading, and therefore it is not required to turn off the wind farm.

[0008] On the other hand, even with relatively low light intensity, disturbing shade can occur. This can be determined simply by measuring the difference in brightness between light and shadow.

[0009] As is known, the position of the sun depends on the season and time of day and can be determined by measuring or using calculation programs for each appropriate point of immission (place (area) where shading may occur). The basis forTherefore, the shutdown of a wind farm as a result of shading are the calculated periods in which due to the location of the sun and the geographical location of the power plant the neighborhood may be shaded (at the point of immission). Parallel to specific periods of sun position, the difference between light and shadow is recorded by means of light sensors and in this way the probability of shading occurring is checked. Only when a shadow occurs during these predetermined periods of position of the sun during which shading at the immission point is possible does the wind farm shut down as a result of shading.

[0010] Shutdown due to shading can be operated in a wind farm according to the invention by means of an input / display device (LCD display). To do this, you can read the settings or values ​​of the current light intensity and the difference between light and shade. In addition, the display can show information about the instantaneous state of the shutdown system, i.e. whether it is turned on or off, relatively active or inactive. With the help of an independent menu, you can enter or load data about the switch-off periods.

[0011] In the "off due to shading" mode, the following parameters are presented: current first value of light intensity (in direct light) (value in%), current second value of light intensity (in the shaded area) (value in%), difference at switch-off (value in%), switch-off due to shading (on / off) or switch-off due to shading (active / inactive). The difference when switching off is the value between the first value of light intensity (direct light incidence) and the second value of light intensity (shading) for which the wind power plant should be turned off. For example, in a situation where the wind farm is very close to the point of immission, even in the case of a slightly cloudy sky, the shading may disturb. Therefore, in this case (when the wind farm is very close to the given immission point) the power plant should have a lower value of the difference at shutdown than when the immission point is further away from the wind farm. With respect to the light intensity value, the lower percentage means low light intensity (e.g. in overcast skies), and the high percentage means high light intensity (e.g. under direct sunlight), indicating that solar radiation is not disturbed by cloud cover or fog. Shading off (on / off) indicates whether it is on at all. Shading off (active / inactive) indicates whether the power plant is currently off due to shading.

[0012] If, with respect to the difference, the value obtained is above the difference at switch-off and at the same time there is compliance within the given time interval, which takes into account the sun exposure or the position of the sun, the wind farm will automatically stop, provided that the switch-off due to shading is set to " On ". While the power plant is stopped due to the shadow being cast, a corresponding message about the power plant status is displayed in the main menu of the device with a display.

[0013] The value of the switch-off difference can be changed by entering the relevant information. Since the shadow of the rotor blades with the increasing distance from the point of immission becomes weaker, to lose its significance at some point, the cast shadow adversely affects with increasing distance only at a higher difference value. Set the switch-off difference value according to local conditions, because the switch-off difference also depends on the geographical conditions of the location.

[0014] The lighting conditions are constantly measured, even after the plant is stopped. The wind power plant starts again when the lower limit value of the difference is exceeded when switched off for a period of more than 2 minutes, preferably 10 minutes, or the shadow shifts enough (due to the change in the position of the sun or the path of the sun) that there are no more disturbances caused by casting a shadow at the point of immission.

[0015] The reported shading periods are edited using the menu. These values ​​are the start date and end date as well as the start and stop time. The given values ​​can be changed at any time, extended or deleted, which can be done manually or by loading the appropriate program.

[0016] Sun position periods are introduced using winter time. Leap years are also taken into account during programming.

[0017] Shut-down periods due to shading can be obtained continuously on an ongoing or timely basis via remote control, which allows proof of compliance.

[0018] A wind farm enabling the implementation of the above method includes a data processing device in which the positions of the sun or the corresponding data are recorded. In addition, the wind power plant comprises a number, preferably three light sensors. These sensors are arranged around the power plant with equal spacing.

[0019] When three sensors are used, a gap of 120 ° is obtained between successive sensors when they are located along a circle around the wind farm. When three sensors are used, one of them is constantly exposed to direct light, and at least one more is in the shaded area. Therefore, the difference in light intensity can be constantly measured.

[0020] The invention is discussed further below based on an embodiment.

Fig. 1 shows a side view of a wind farm according to the invention;

Fig. 2 schematically shows a top view of the cross section of the tower over the light sensors;

Figure 3 is a side view of the shadow cast at two different sun positions;

Figure 4 is a top view of the shadow cast at two different sun positions.

[0021] Figure 1 schematically shows the wind farm 1 in a side view.

[0022] The wind power plant 1 comprises a tower 10 on whose head a nacelle 12 is placed together with rotor blades 14. At a predetermined height on the tower 10 there are sensors 16 for measuring light intensity. By placing the sensors 16 at a predetermined height, they are significantly protected against intentional damage or manipulation.

[0023] This height can be selected in such a way as to provide access to the sensors 16 without undue hardship, for example to allow cleaning or replacement. Of course, it is also possible to provide heating for sensors 16 to prevent or remove the ice cover.

[0024] As an alternative to mounting the sensors 16 on the tower 10 of the wind farm 1, the sensors 16 can of course be placed on independent masts (not shown in the drawing) or other adapted devices.

[0025] Figure 2 is a simplified cross section through the tower 10 of the wind farm 1 above the sensors

16. The figure shows that three sensors 16 are preferably positioned here with equal distances along the outer circumference of the tower 10. The distance between the sensors is in^utc ¹²⁰°.

[0026] Due to the circular cross-section of the tower 10, half of the peripheral surface of the tower 10, i.e. the region of 180 °, is constantly exposed to direct light. Correspondingly, the other half of the peripheral surface (again 180 °) will then be shaded. Thus, by using at least three sensors, at least one is exposed to direct light, and at least one is in the shade.

As a result, it is possible to determine the light intensity at direct light incidence and the light intensity in the shade at any time and calculate the difference on this basis. This difference can be calculated by the power plant control system and at the same time be used to control the wind power plant according to the invention.

[0028] Fig. 3 shows a wind power plant, for example of the Enercon type E-40, which is located at a distance E from building 2. Building 2 can also be defined as point of immunity A.

[0029] When the sun rises in the morning, or throughout the day in winter, it rises - if viewed from immission point A - to a small height, as a result of which the angle of incidence βΐ is obtained for the position of sun I.

[0030] When the sun is higher - which corresponds to the position of the sun ΐΐ - a different angle of incidence αΐΐ of the sun's rays is obtained. The incidence angles of βΐ and βΐΐ (any other values ​​of incidence angles are possible) of the sun's rays determine at the same time when the shadow may fall directly on the point of immission A.

[0031] The situation in Fig. 3 is shown again in Fig. 4 from a different perspective. When the sun is in the south-east (again: if you look from the point of immission), the sun's rays fall at an angle of βΐ - relative to the east-west axis - on the wind farm.

[0032] When the sun moves further south, the sun's rays will fall at a different angle βΙΙ on wind farm 1.

[0033] Only when the position of the sun, which is a function of the geographical location on the earth and the angle of incidence α and β, causes the shadow of the wind power plant reaches its immission point A, the wind power plant will be turned off when the difference between light and shadow is above a certain value, i.e. the difference when switching off. The difference when switching off depends not only on the incident light, but also on the distance from the point of immission. When a wind farm is very close to the point of immission, shadows can disturb even when the sky is overcast. In this case, the wind farm should get a lower value of the difference at shutdown than when the immission point is further away from the wind farm.

[0034] When the difference value is below the difference when turned off, the wind farm is not turned off regardless of the position of the sun and can still generate electricity. This situation occurs especially in heavy cloud cover.

[0035] The further from the immission point the wind farm is, the shorter the periods in which shading can occur at the immission point.

[0036] The difference can be calculated directly at the point of immission A or at the wind farm. Because the immission point and wind farm are relatively close together, the light intensity values ​​measured at the wind farm are also valid for immission point A.

[0037] The difference itself can, for example, be measured using a number of light sensors, the values ​​obtained being processed by a data processing unit allocated to a wind power plant. The data processing device also has sun positions programmed for which shading can occur at the point of immission. It is clear that shady sun positions vary depending on the wind farm, so the data processing device stores for the wind farm other information about the position of the sun at which shading can occur.

[0038] Of course, it is also possible that in the case of a wind farm close to the immission point, where shading should be avoided, this process should be controlled by means of a central data processing device that switches off a given wind farm within a wind farm when due to it there is shading at the point of issue.

[0039] When shading occurs, switching off does not take place immediately, but only when the shading lasts for a certain period of time, for example 5 to 10 minutes.

[0040] When the shading is no longer present, for example because clouds have appeared between the sun and the wind farm, a solution can also be used whereby the wind farm is not switched on again immediately but after a certain waiting time, for example 5 to 10 minutes. Only then can you ensure that the wind power plant is switched on and operational again, when during this time the difference value was below the difference value at switch-off.

[0041] It is also possible to program next to the already programmed sun positions when turning off further sun positions for a wind power plant, if necessary.

Aloys Wobben

Proxy: