DE102016124398A1 - Determination of an icefall and / or ice throw distribution of a wind energy plant - Google Patents

Abstract

The invention relates to a method for determining an icefall and / or ice throw distribution for a wind energy plant, characterized in that for determining the icefall and / or ice throw distribution system data of the wind turbine, environmental data of the wind turbine and a Eisstückcharakteristik concerning located on the wind turbine ice are used. Furthermore, the method is characterized in that the icefall and / or ice throw distribution is determined on the basis of the system data, the environmental data and the Eisstückcharakteristik via a calculation by means of a Monte Carlo algorithm.

Description

The invention relates to a method for determining an icefall and / or ice throw distribution for a wind energy plant. The invention further relates to a method for operating a wind energy plant.

The invention also relates to a wind turbine with a warning device, a software and a wind farm.

At low ambient temperatures, rotor blades of a wind energy plant can form ice, which hinders the efficient and safe operation of the wind energy plant. To avoid this, usually heating devices are installed in the rotor blades of a wind turbine. Thus, under appropriate weather conditions, intentional or unintentional detachment of pieces of ice from the rotor blades may occur, which fall into an area surrounding the wind energy plant.

In this area there is a risk that external objects may be damaged by falling pieces of ice or that a human being or an animal may be injured.

This danger is typically reduced by shutting down the wind turbine.

DE 10 2011 082 249 A1 describes a basic method for defrosting a wind turbine with a defrost control device by means of which a de-icing process can be carried out, in which ice adhering to the wind turbine is at least partially released and falls into a monitored danger zone below the wind turbine. The danger area is generously dimensioned. In particular, it should be noted that falling ice may be blown by wind or can be thrown sideways by the rotor blades by a rotational movement of the rotor blades and thereby impinges on the ground only at some distance from the wind turbine.

The danger area is therefore at best estimated and then generously dimensioned. A reliable determination of the danger area is not given, so that one relies so far on a generous estimate of the same, in order to avoid dangers by ice fall or ice throw.

At best, such a danger area is currently estimated from the rotor blades by using empirical values for an icefall and / or ice throw - for example, by observing an actually determined ice piece distribution in a 600 kW Enercon E-40 wind energy plant ( Cattin, R., A. Heimo, S. Kunz, G. Russi, M. Russi, M. Tiefgraber, S. Schaffner, BE Nygaard: Alpine Test Site Guetsch - Meteorological measurements and wind turbine performance analysis. IWAIS XII, Yokohama, October 2007 ).

oder einer Anlage im Betrieb: $$d=\left(D+H\right)\cdot 1.5$$

Baring-Gould et al. (IEA, "Wind Energy Projects in Cold Climates", 2011) describes a risk assessment of the ice throw of wind turbines in order to estimate a suitable distance between the wind turbine and the adjacent road depending on the location - but only within the scope of a risk statement. This is only a risk analysis based on known incidents, ice classifications and their probability of occurrence and simplest empirical formulas - for example, to determine a maximum distance d of ice in a stationary wind turbine $$d=V\frac{D\text{/}2+H}{15}$$

or a plant in operation: $$d=\left(D+H\right)\cdot 1.5$$

For this purpose, predetermined system data for a specific type of wind turbine with a rotor diameter D, the hub height H and empirical values or statistical assumptions for determining an average wind speed V are used.

The problem with the known consideration of a previously estimated maximum danger area below the wind turbine is the poor possibility of assessing the danger to humans and animals at the edge of the danger area or beyond the danger area. Due to the lack of precision of a danger area based entirely on empirical values, a reliable and / or conservative determination of a danger zone or its boundary can not already be given and certainly not transferred to new model types of wind turbines. The approaches known so far are hardly suitable for the reliable planning of sites of wind turbines or a wind farm or other applications, which require a higher reliability of a danger area or a limit of the same.

At this point, the invention begins, whose task is to address at least one of the above-mentioned problems. In particular, it is an object of the invention to provide a method for the reliable and / or conservative determination of an icefall and / or ice throw distribution of wind turbines, in particular to determine a risk of icefall and / or ice throw on certain areas in the vicinity of a wind turbine. In particular, it is an object to provide a method which allows an improved location-specific determination of the icefall and / or ice throw distribution.

• - zur Bestimmung der Eisfall- und/oder Eiswurfverteilung einer Windenergieanlage verwendet werden:
  • Anlagendaten, insbesondere weitgehend vorbestimmte oder bestimmbare Anlagendaten, bevorzugt statische Anlagendaten der Windenergieanlage, und
  • Umgebungsdaten, insbesondere weitgehend variable Umgebungsdaten der Windenergieanlage,
  • eine Eisstückcharakteristik, und dass
• - die Eisfall- und/oder Eiswurfverteilung auf Basis der Anlagendaten, der Umgebungsdaten und der Eisstückcharakteristik über eine Berechnung mittels eines Monte Carlo Algorithmus bestimmt wird.

The object is achieved according to a first aspect of the invention by a method for determining an icefall and / or ice throw distribution according to claim 1. According to the invention it is provided that

• - be used to determine the icefall and / or ice throw distribution of a wind turbine:
  • Plant data, in particular largely predetermined or determinable plant data, preferably static plant data of the wind turbine, and
  • Environmental data, in particular largely variable environmental data of the wind turbine,
  • a Eisstückcharakteristik, and that
• the icefall and / or ice throw distribution is determined on the basis of the plant data, the environmental data and the ice piece characteristic via a calculation by means of a Monte Carlo algorithm.

The invention is based on the consideration that in the context of an icefall and / or ice throw many parameters, such as the average size of a piece of ice, the wind speed or the temperature, behave stochastically over time, so that there is no firm limit to the danger area for falling down of detached pieces of ice can be stated. It is therefore only possible to indicate the probability where the risk of ice throwing rather large and where the danger is rather small.

It has been recognized within the scope of the invention that, in view of the stochastic parameters of the icefall or ice throw, that is to say the stochastic properties of the ice piece characteristic, it is advantageous, via a Monte Carlo algorithm, to determine a frequency distribution for the occurrence of the icefall and / or ice throw in an area to create a wind turbine and based thereon to determine an icefall and / or ice throw distribution around the wind turbine. Furthermore, it was recognized that the use of corresponding random values is advantageous for the most realistic possible consideration of stochastically distributed data. This makes it particularly advantageous not only to specify a fixed safety distance to a wind turbine, but to determine the specific risk of icing in an area in the vicinity of the wind turbine.

The method according to the invention advantageously makes it possible to deliberately determine an icebound zone based on a concrete predetermined residual risk for the icefall and / or ice throw outside of the icebox zone. Thus, it can be ensured by the method according to the invention that on the average, only every one hundredth or every thousandth or only every ten thousandth icefall and / or ice throw, or just any other number of ice falls and / or ice throws, is likely to be outside the ice-covered zones - ie Depending on how the ice rink zone is determined on the basis of the calculated icefall and / or ice throw distribution, the method according to the invention can calculate that the risk of impact due to icefall and / or ice throw is below a predetermined limit value. Advantageously, it is no longer or only to a limited extent necessary to dimension an icebound zone beyond the dimensions - rather, the iceflon zone can be reliably adapted to current needs, and in particular to current conditions, in particular the meteorological conditions.

Another advantage of the presented method is that it leads to an icefall and / or ice throw distribution that allows qualitatively and quantitatively verifiable statements. So can the choice of the predetermined System data or the estimation of the variable environment data in the context of the Monte Carlo algorithm checked and if necessary adapted to the reality.

The icefall and / or ice throw distribution is preferably not distributed homogeneously around the wind energy plant, for example due to a prevailing wind direction at the location of the wind power plant.

Icefall is understood to mean the falling off of ice pieces from the wind energy plant during stationary operation of the wind energy plant. Ice casting refers to the ejection of pieces of ice, which is influenced by a movement of a rotor blade of the wind power plant, preferably ejection of ice pieces during active operation of the wind energy plant.

In the context of this invention, the Monte Carlo algorithm is understood to be a randomized, ie random-based, algorithm which, by repeatedly executing a calculation rule with alternating random values for a particular parameter of the calculation specification, yields a result with a corresponding inaccuracy. Typically, the size of the inaccuracy is known by a corresponding modeling of the Monte Carlo algorithm, in particular by a number of random values used.

The invention leads according to a further aspect of a method for operating a wind turbine. In the context of this method according to the invention, the icefall and / or ice throw distribution is determined according to an embodiment of the method according to the first aspect of the invention, wherein depending on the icefall and / or ice throw distribution triggers a shutdown of the wind turbine and / or issuing a warning signal for security if the probability of an ice throw and / or icefall on an external object exceeds a predetermined limit.

The invention relates in particular according to a further aspect of the invention, a wind turbine with a warning device. The warning device is configured to trigger a warning signal if the probability of an ice throw and / or icefall to an external object by the wind turbine exceeds a predetermined limit, the probability of an ice throw and / or icefall on an external object by a method according to the first Aspect of the invention is determined.

The wind energy plant according to the invention triggers a warning signal advantageous when the external object is within an area around the wind turbine, in which with a predetermined probability icefall and / or ice throw goes to the ground. Therefore, this area is preferably defined as an icebound zone, ie as a local area with an increased risk of ice-skating. The warning signal can therefore advantageously serve to prevent the external object from further approaching the wind turbine or to make it move away from the wind turbine. In this case, the warning signal can be, for example, an audible tone, a visually perceptible signal, or particularly preferably an electronic message to an operator of the wind energy plant.

The warning signal can also trigger a shutdown of the wind turbine immediately.

The invention also leads to software having program means with a module adapted to control a method for determining an icefall and / or ice throw distribution of a wind turbine via a Monte Carlo algorithm according to the method of the invention.

In addition, according to another aspect, the invention relates to a wind farm having a park iceback zone. The wind farm has a plurality of wind turbines of one or more park sections, wherein wind turbines of one or more parking sections are connected to each other via at least one common feed point for connection to a supply network. The wind farm has a warning device which is designed to trigger a warning signal if the probability of an ice throw and / or ice fall on an external object by a wind turbine of the wind farm exceeds a predetermined limit. The probability of an ice throw and / or ice fall on an external object is determined for each wind turbine of the wind farm each by a method for determining an icefall and / or ice throw distribution according to the first aspect of the invention.

The wind farm with the warning device is particularly advantageous since the icefall and / or ice throw probability can be centrally determined for all wind energy installations of the wind farm and monitored accordingly. Furthermore, the determination and the possible monitoring of a parking Ice-break zone for the entire wind farm reduces the risk of damage or injury due to icing and / or ice throwing in the vicinity of the wind farm.

Further advantageous developments of the invention can be found in the subclaims and specify in detail advantageous possibilities to realize the above-described concept within the scope of the problem as well as with regard to further advantages.

In the method according to the first aspect of the invention, in an advantageous development, the icefall and / or ice throw distribution is calculated via a multiplicity of icefall and / or ice throw trajectories. The various icefall and / or ice trajectories correspond to different parameters that are used within the framework of the Monte Carlo algorithm. In particular, it is advantageous to calculate a corresponding icefall and / or ice throw trajectory for each random piece of ice determined for a piece of ice or for random data based on random values. As a result, the icefall and / or ice throw distribution can be determined by storing meeting points of the icefall and / or ice throw trajectories on the ground and merging them into an icefall and / or ice throw frequency, which results in the icefall and / or ice throw distribution , The icefall and / or ice trajectories are typically dependent on the predefined plant data of the wind turbine and the environmental data of the wind turbine. Preferably, a trajectory model is used for the calculation of the icefall and / or ice trajectories that takes into account the finite extent of the ice pieces.

$$M\frac{d^{2}y}{d{t}^2}=-\frac{1}{2}\rho C_{D}A\left(\frac{dy}{dt}\right)\left|V\right|$$

$$M\frac{d^{2}z}{d{t}^2}=-Mg-\frac{1}{2}\rho C_{D}A\left(\frac{dz}{dt}U\right)\left|V\right|$$

In a variant of this development, the icefall and / or ice throw distribution is based on an at least two-dimensional equation of motion of the icefall and / or ice throw in a plane formed by the rotor blades of the wind energy plant, in particular a two- or three-dimensional equation of motion, preferably based on a three-dimensional equation of motion, calculated. By using the environmental data, the equation of motion captures influences of the surroundings on the icefall and / or ice throw, such as a wind speed and wind direction, a corresponding frictional resistance of a piece of ice in the air and the force of gravity acting on the ice piece. In a particularly preferred variant of the three-dimensional equation of motion, the following three differential equations are used as a three-dimensional equation of motion: $$M\frac{d^{2}x}{d{t}^2}=-\frac{1}{2}\rho C_{D}A\left(\frac{dx}{dt}-U\right)\left|V\right|$$

$$M\frac{d^{2}y}{d{t}^2}=-\frac{1}{2}\rho C_{D}A\left(\frac{dy}{dt}\right)\left|V\right|$$

$$M\frac{d^{2}z}{d{t}^2}=-MG-\frac{1}{2}\rho C_{D}A\left(\frac{dz}{dt}U\right)\left|V\right|$$

The z-axis describes a direction that is perpendicular to the Earth's surface. Here M stands for the mass of a piece of ice, g is the gravitational acceleration, | V | represents the amount of speed of the ice, in particular, according to a simplified assumption, | V | for the initial speed of the ice lump, C _D stands for the coefficient of friction of the air friction (assumed Newton friction), A for the dragged cross-sectional area of a piece of ice relevant to the air resistance, U stands for the wind speed and ρ for the density of the air.

In a further variant, the method comprises determining the icefall and / or ice throw distribution on the basis of a two-dimensional equation of motion, wherein the above equations (1) and (3) are used for the respective calculation of the ice throw trajectories. Here, the x-axis is preferably perpendicular to the z-axis in the plane formed by the rotor blades of the wind turbine.

In a particularly preferred development, the system data are predetermined system data. These result from a past state of the wind turbine in a deterministic manner. In particular, the plant data comprise structural plant data relating to the structure of the wind turbine, such as a rotor diameter, a hub height of the wind turbine, a blade angle curve or other data for dimensioning the rotor blade. Other predetermined system data may be, for example: turbine type of the wind turbine, a maximum rotational speed of the wind turbine and a presence of a heater in the wind turbine and optionally an operating state of the heater. In one variant, the plant data also have a non-deterministic portion, which is estimated to determine the plant data.

Furthermore, the system data include input and / or measured system data in a development, which vary within the scope of an operation of the wind turbine and are therefore not predetermined, such as the speed of the rotor blades, so affect the operation of the wind turbine.

In a further development, the environmental data include, among other things, weather data, such as an average temperature, an average wind speed, a mean wind direction, or a predetermined ice classification. This environment data may be provided in a predetermined manner and therefore does not require continuous measurement.

The ice classification of a location of the wind energy plant can, for example, be carried out by the ice classification given by the research cooperation IEA Wind according to Table 1. Table 1 icing class Meteorological icing (in% of the year) Instrument icing (% of the year) Loss of productivity (% of annual energy yield for a wind turbine without blade heating) 5 > 10 > 20 > 20 4 5-10 10-30 10-25 3 3-5 6-15 3-12 2 0.5-3 1-9 0.5-5 1 0-0.5 0-1.5 0-0.5

In a development, the environmental data of the wind energy installation are temporally unforeseeable variable environmental data, in particular variable environmental data. The variable environment data defies a deterministic prediction, as is the case, for example, for weather data or a time of ice formation on the rotor blades. Therefore, determination by setting corresponding random values is particularly advantageous. In this case, the random values can be determined, for example, via known random number generators or via stored random number tables.

In a further preferred development, variable environmental data depend on predetermined environmental data. For example, the statistical distribution of the average wind speed, which i.a. according to the Weibull distribution, a site-specific predeterminable value, whereas the instantaneous wind speed is a part of the indefinite environment data. For example, a random value of the wind speed may be statistically determined via the Monte Carlo algorithm using the Weibull distribution. Time-varying values often elude a precise prediction. Therefore, their determination by means of random values in a given statistical framework is particularly advantageous, as it statistically takes into account various possible temporal changes of these values, that is to say the indeterminate environmental data.

In a preferred embodiment, the ice piece characteristic is calculated from random values for a surface of a piece of ice, a volume of a piece of ice, a mass of a piece of ice, a position of a piece of ice on a rotor blade of the wind turbine, or a combination thereof. The expression of ice pieces eludes a predictive, deterministic view, so that their consideration by random values is particularly advantageous. For the modeling of such random values known ice fragment modeling can be used. This is advantageous in a variant of the invention resorting to the present icing class of the location of the wind turbine or to present weather data for ice fragment modeling.

In a preferred development, the determination of the icefall and / or ice throw distribution is based on random values for the area and the mass of a piece of ice. In accordance with the known density of ice, instead of the mass, random values for the volume can also be determined.

In a further particularly preferred development, the determination of the icefall and / or ice throw distribution is based on random values for the ratio of area to mass, A / M of a piece of ice. In this development, a necessary number of random values to be determined can be reduced in that A and M are not determined individually via random values, but only a single random value is used for the ratio of the two sizes of the ice piece characteristic.

Preferably, the ice piece characteristic is based on an ice classification of the location of the wind turbine. Such an ice classification can be, for example, the ice classification given by the IEA Wind research cooperation in accordance with Table 1.

The Eisstückcharakteristik includes in a development also predetermined data, for example: an average weight of ice pieces, an average number of pieces of ice on a rotor blade of the wind turbine, a proportion of thrown ice pieces of the rotor blade or a mean residence time of ice pieces on the rotor blade. Such predetermined data of the ice piece characteristic are particularly preferably dependent on the ice classification prevailing at the location of the wind energy plant.

The determination of random values preferably takes place here by setting an average value, for example for the mass and / or an A / M ratio of a piece of ice, corresponding to a used ice fragment modeling and a randomly determined deviation from this mean value. A variance of this deviation is also given in the context of ice fragment modeling or by empirical values from earlier measurements in an example of this development.

In principle, in the context of the method according to the invention, it is preferable to use such assumptions for ice formation and / or environmental influences and corresponding indeterminate environmental data, which are based on assumptions known in the field or can be substantiated by industry by long-term corresponding time series.

• - Bereitstellen der, insbesondere vorbestimmten, Anlagendaten der Windenergieanlage;
• - Festlegen oder Messen der Umgebungsdaten der Windenergieanlage;
• - Festlegen einer Vielzahl von Zufallswerten für die Eisstückcharakteristik, zumindest teilweise basierend auf den Umgebungsdaten;
• - Berechnen einer Vielzahl von Eisfall- und/oder Eiswurf-Trajektorien, auf Basis der, insbesondere vorbestimmten, Anlagendaten, der Umgebungsdaten und der Vielzahl von Zufallswerten für die Eisstückcharakteristik;
• - Bestimmen der Eisfall- und/oder Eiswurfverteilung aus der Vielzahl von Eisfall- und/oder Eiswurf-Trajektorien.

In a particularly preferred development, the method according to the first aspect of the invention comprises the following steps

• - Providing the, in particular predetermined, system data of the wind turbine;
• - determining or measuring the environmental data of the wind turbine;
• Setting a plurality of ice piece characteristic random values based, at least in part, on the environmental data;
• Calculating a plurality of icefall and / or ice trajectories based on, in particular predetermined, system data, the environmental data, and the plurality of ice pieces characteristic random values;
• Determining the icefall and / or ice throw distribution from the plurality of icefall and / or ice throw trajectories.

Preferably, the method according to the invention also includes recording current weather data averaged over a previous period of time for providing the, in particular predetermined, environmental data. In this way, the calculated icefall and / or ice throw distribution can be adapted to meteorological conditions of the location of the wind energy plant.

In a further development of the method according to the invention, an ice-floe zone around the wind energy plant is furthermore determined on the basis of the icefall and / or ice throw distribution. In this case, the ice-rink zone represents an area around the wind energy plant, in which the probability of an ice throw and / or ice fall on an external object by the wind energy plant exceeds a predetermined limit value.

Since the nacelle of the wind turbine is usually rotatably mounted, the icicle zone, depending on the wind distribution, for example, set approximately circularly around the wind turbine. Alternatively, it may also be approximately rectangular, ellipsoidal or polygonal. In this case, the dimensions of the icebreaking zone are determined by properties of the icefall and / or ice throw distribution.

In a further development, the method comprises the step of comparing the ice-breaking zone determined on the basis of the icefall and / or ice throw distribution with a conventional icebreaking zone that is deterministically calculated on the basis of in particular predetermined system data. The icebreaking zone of the wind energy installation is selected, selected from the ice impact zone determined on the basis of the icefall and / or ice throw distribution, and the deterministically calculated conventional ice impact zone, which has a smaller area around the wind energy installation. In this development, an existing possibly to the wind turbines usable area is increased. The method according to the invention is so reliable that, given an ice-rink zone which is smaller than a conventionally estimated ice-rinking zone, the ice-rinking zone determined according to the invention is to be preferred due to its location-specific parameters. The reduction of the area to be protected for the operation of a wind power plant around the wind power plant is a central advantage of the method according to the invention in all developments. In this case, there is no reduction in protection against icing below a reasonable level. A comparison of the ice-hammertone zone determined according to the invention with the conventional icebreaking zone deterministically calculated on the basis of predetermined plant data is also advantageous in that incorrect assumptions or errors can be quickly recognized in the context of the method according to the invention. The deterministically calculated conventional ice-floe zone can be determined, for example, via the known safety distance calculation according to publications by Baring-Gould et al. (IEA, "Wind Energy Projects in Cold Climates", 2011) respectively. In this case, all parameters used for the analysis are predetermined for the calculation of the conventional ice-floe zone, as discussed above in the context of equations (1) and (2).

In a particularly preferred embodiment, the random values are randomized, in particular the icefall and / or ice throw distribution is estimated on the basis of preferably more than 1,000,000 repetitions of specifying randomized random values. The greater the number of repetitions, the higher the likelihood that the determined icefall and / or ice throw distribution, within the framework of the Monte Carlo algorithm's assumptions regarding the environmental influences and the properties of the wind turbine, will be exact and hence the environmental influences and The properties of the wind turbine realistic. In another alternative development, only a small number of repetitions are used to shorten the duration of the calculation under the Monte Carlo algorithm.

The ice-rink zone or the icefall and / or ice-throw probability is preferably used in the planning of the location of a wind energy plant in order to plan the location in accordance with the regionally available weather data and the external objects present in the vicinity of the wind energy plant. Thus, surfaces provided for the wind power plant, in particular for a large number of wind energy installations, can be used effectively without thereby increasing the risk of icefall and / or icing. Thus, the icefall and / or ice throw characteristics can be used advantageously for a design, expansion or planning of a wind farm.

The wind energy installation with a warning device according to a further aspect of the invention has, in a further development, a storage unit which is designed to store and output ice impact zone data which has information on properties of an ice impact zone defined by the icefall and / or ice throw distribution (80).

The software according to another aspect of the invention is preferably performed on an external device that is not connected to the wind turbine. In alternative developments, the software is executed by a computer located within the wind turbine or electronically connected to the wind turbine, the access to current system data, such as a current speed of the rotor and according to the current system data, the predetermined system data of the wind turbine for the implementation of the Monte Carlo algorithm determines. This is particularly advantageous for a further development in which the ice-rink zone is newly set at regular intervals, for example daily or weekly, and is adapted to current weather data and system data, such as a state of a heating device of the wind energy plant. As a result, an adaptation of the icicle zone to the current weather situation or other seasonal or temporary influences on the plant data can advantageously take place. As part of a regular determination of the icing zone can also be estimated whether a heater of the wind turbine should be used or whether the operating condition of any existing leaf heater should be adjusted. However, the speed used for the Monte Carlo algorithm can also be determined taking into account the plant design and the plant location, without evaluating current plant data.

The software according to the further aspect of the invention is preferably adapted to improve a park design of a wind farm, or to adapt the location specification of a wind turbine to a present location characteristic. In a further development, the software is designed to trigger an operation stop of the wind energy plant and / or a warning signal if the probability of an ice throw and / or ice fall on an external object by the wind energy plant exceeds a predetermined limit.

Embodiments of the invention will now be described below with reference to the drawing. These are not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be understood that various modifications and changes may be made in the form and detail of an embodiment without departing from the general spirit of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article that would be limited in comparison with the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing.

• 1 ein Schema eines Verfahrens zur Bestimmung einer Eisschlagzone für eine Windenergieanlage betreffend Eisfall und/oder Eiswurf, im Rahmen einer bevorzugten Ausführungsform gemäß einem ersten Aspekt der Erfindung;
• 2a, 2b eine Illustration einer bekannten deterministisch berechneten konventionellen Eisschlagzone (2a) und einer Eisfall- und/oder Eiswurfverteilung, die im Rahmen des erfindungsgemäßen Verfahrens gemäß dem ersten Aspekt der Erfindung berechnet wurde (2b);
• 3 den Aufbau einer Windenergieanlage mit einem Turm und einer Gondel -vorliegend mit einer Warnvorrichtung, die ausgebildet ist, ein Warnsignal auszulösen-- im Rahmen einer bevorzugten Ausführungsform der Erfindung;
• 4 den Aufbau einer Windenergieanlage mit einem Turm und einer Gondel -vorliegend mit einem Schutzmittel, das ausgebildet ist, eine Eisschlagzone der Windenergieanlage gegen unbefugtes Betreten zu sichern-- im Rahmen einer weiteren Ausführungsform der Erfindung;
• 5 den Aufbau eines Windparks mit einem Parkabschnitt und mindestens einem gemeinsamen Einspeisepunkt zum Anschluss an ein Versorgungsnetz -- vorliegend mit einer Park-Eisschlagzone, die anhand von Eisschlagzonen der einzelnen Windenergieanlagen festgelegt ist -- im Rahmen einer besonders bevorzugten Ausführungsform der Erfindung.

In detail, the drawing shows in:

• 1 a schematic of a method for determining an icing zone for a wind turbine concerning icefall and / or ice throw, in a preferred embodiment according to a first aspect of the invention;
• 2a . 2 B an illustration of a known deterministically calculated conventional ice-floe zone ( 2a ) and an icefall and / or ice throw distribution, which was calculated in the context of the method according to the first aspect of the invention ( 2 B );
• 3 the construction of a wind turbine with a tower and a gondola-present with a warning device which is designed to trigger a warning signal - in a preferred embodiment of the invention;
• 4 the construction of a wind turbine with a tower and a gondola present with a protective means, which is designed to secure an icebreaking zone of the wind turbine against unauthorized entry - in the context of a further embodiment of the invention;
• 5 the construction of a wind farm with a parking section and at least one common feed point for connection to a supply network - in the present case with a park icebreaker zone, which is determined on the basis of ice rinks of the individual wind turbines - in a particularly preferred embodiment of the invention.

1 shows a schematic of a method 5 for determining an icebreaking zone for a wind energy installation concerning icefall and / or ice throw, within the scope of a preferred embodiment according to a first aspect of the invention.

The procedure 5 points in a first step 10 providing plant data of the wind turbine. In the present embodiment, these are entered and measured system data. Entered predetermined plant data are a hub height of the wind turbine, a maximum rotational speed of rotor blades of the wind turbine and the rotor blade diameter. Measured system data are the rotational speeds of the rotor blades, a present heating mode of a heater in the wind turbine and an indication of whether the rotor blades of the wind turbine rotate.

In a further step 20 are, in particular indefinite, environmental data of the wind turbine via random values set and provided. The environmental data is at least partially around time-varying environmental data, such as a wind direction, a wind speed or an outside temperature. In detail, for example, a random value for a rotor blade angle can be set by determining a random value P between 0 and 1, multiplying this random value P by 2 * Pi, and thus obtaining a random value between 0 and 2 * Pi. Analogously, a random, normally distributed deviation from a known average can be realized, for example, via the known Box-Müller method.

In a further step 30 Random values are determined based on an ice piece characteristic based on the environmental data. In this case, in particular random data for a weight, a position of a piece of ice located on the rotor blade of the wind turbine and for an outer surface of the ice block are determined.

A next step 40 includes determining an icefall and / or ice throw trajectory of a piece of ice based on the plant data, the random values of the environmental data and the random values determined via the ice piece characteristic via a Monte Carlo algorithm.

In this case, above all, the predetermined system data and, in particular, the undetermined environmental data are used in order to carry out the steps repeatedly 20 and 30 to calculate a variety of ice trajectories. The icefall and / or ice throw trajectory is calculated using the three-dimensional equation of motion given above, which results from the component-by-component representation of equations (1), (2) and (3). After the calculation of a single icefall and / or ice throw trajectory, a determination of new random values and a corresponding calculation of a next icefall and / or ice throw trajectory based on the new random values takes place. Such a repetition of the calculation of an icefall and / or ice throw trajectory preferably takes place over 1,000,000 times in the course of determining the icefall and / or ice throw distribution.

In the present case, it is provided that in step 40 an ice throw trajectory is calculated using the in steps 20 and 30 certain random values, ie in particular using a Eisstückcharakteristik. Specifically, the ice piece characteristic takes into account one or more of the following parameters alone or in combination: a surface of a piece of ice, a mass of a piece of ice, a position of one on a rotor blade 108 the wind turbine 100 ice piece. It can in particular the determination of the icefall and / or ice throw distribution 80 based on random values for the area and mass of a piece of ice.

A combination of these parameters has proved to be particularly advantageous and relates in particular to a ratio such as the determination of icefall and / or ice throw distribution 80 due to random values for the area to mass ratio A / M of a piece of ice.

The ice lump characteristic may advantageously take into account ice classification of the location of the wind turbine, based on the values of area to mass A / M ratio of a lump of ice. Ice classification orders a particular type of ice, e.g. according to a specific ratio of area to mass A / M of a piece of ice, but also in alternative embodiments according to shape, surface or structure. Advantageously, the occurrence of a certain ice class can be assigned to specific environmental conditions, such as, for example, a quantity of ice on a rotor blade of the wind energy plant.

In the following step 50 Impact points of the icefall and / or ice trajectories are calculated on the ground and based on these impact points, the icefall and / or ice throw distribution of the wind turbine is calculated. The icefall and / or ice throw distribution in this embodiment is a two-dimensional probability distribution for an ice block impact in an area surrounding the wind turbine. A more detailed description of the icefall and / or ice throw distribution is within the scope of 2 B shown.

In an alternative embodiment not shown, the steps become 20 and 30 not randomly executed, but all random values are determined in one step, and then icefall and / or ice throw trajectories are calculated for all particular random values.

The determination of the egg characteristic is carried out using known ice fragment models. Here, on the basis of an icing class prevailing at the location of the wind energy plant and based on recorded weather information, such as, for example, wind speed, wind direction and wind frequency, a probability distribution for the weight of one of the rotor blades be separated from the detaching piece of ice. In addition, it is advantageous to compare the obtained iceback zone or ice distribution with experimental results.

2 illustrated in the context of 2a a deterministically calculated conventional icebreaking zone 70 around a wind turbine 100 , In this case, the scope of protection became the deterministic calculation of predetermined data, namely hub height and rotor diameter of the wind turbine 100 , and mean wind speed at the location estimated according to equations (1) and (2) given above. It follows from empirical results that outside of an outer protection area 74 the risk of accidents due to icefall and / or ice is very low, and outside of an inner protected area 78 the risk of accidents due to icefall and / or ice is still small. The presented result is thus essentially based on observations made in the past, ie the modeling is based on randomly distributed values and the result on the modeling. A distribution function of randomly distributed values in the result itself can therefore be largely dispensed with - this makes the result relatively accurate and reliable.

2 B shows an icefall and / or ice throw distribution 80 as calculated in the method according to the first aspect of the invention.

One recognizes the wind energy plant 100 a bright area 90 , in which the probability of occurrence of ice is already significantly lower than in the immediate vicinity of the wind turbine 100 , It is also based on a comparison between 2a and 2 B recognizable that the results are comparable for a respective risk assessment, but differences in detailed consideration occur. In particular, the specific ice throw distribution 80 not isotropic around the wind turbine 100 formed so that is east of the wind turbine 100 a larger danger area with respect to icefall / ice throw results than this south of the wind turbine 100 the case is. Such asymmetry based on site-specific data has been identified with the in 2a shown deterministically estimated conventional icefall zone 70 with inner and outer protection area 74 . 78 not recorded.

In an unillustrated embodiment of the method according to the first aspect of the invention, in a final step of the method, a comparison is made between the icing zone determined on the basis of a probabilistic calculation and a deterministically calculated conventional icebreaking zone, and that icicle zone with a smaller one distributed around the wind turbine Surface is finally determined as the final ice-break zone. In this case, the comparison forms an advantageous checking instance in order to find and correct errors in utilized data records. The icicle zone determined according to the invention is particularly trustworthy due to the location reference used and nevertheless, according to previous experience, is lower than the conventionally estimated icicle zone.

3 shows a wind turbine 100 with a tower 102 and a gondola 104 , At the gondola 104 is a rotor 106 with three rotor blades 108 and a hub 110 arranged. The rotor 106 is set in operation by the wind in a rotary motion and thereby drives a generator in the nacelle 104 at.

In addition, the wind turbine indicates 100 a warning device 140 on, with the warning device 140 is designed to trigger a warning signal, if a moving object is within an icebreaking zone 130 the wind turbine 100 located. The icicle zone 130 was determined according to an embodiment of the method according to the first aspect of the invention. The illustrated embodiment of the wind turbine 100 shows that the icicle zone 130 can have a rectangular shape. Any other geometric shape, in particular an elliptical or polygonal shape, is likewise possible, the dimensions of this respective geometric shape, that is to say in particular the present rectangular shape, having been determined in accordance with the determined icefall and / or ice throw distribution.

The warning device 140 is in this embodiment as a camera system 144 formed, which at the tower 102 is attached. The camera system 144 includes two swiveling cameras 146 , for reasons of clarity, only one camera in 3 is shown. The data acquisition by the camera and the corresponding evaluation are carried out automatically.

For the sake of clarity, it is not shown that the warning device 140 a memory unit. The storage unit is designed, ice-rink zone data, which information about properties of the icebreaker zone 130 have to store and output. In the present embodiment, the ice impact zone data is output to a processing unit of the warning device, which is additionally controlled by the camera system 144 recorded data receives. If entering the icicle zone 130 is detected by an object by the processing unit, it is designed to trigger the warning signal.

The warning signal is a flashing lamp in the illustrated embodiment 148 which is adapted to alert a person located within the icebreaker zone to being in an area that is dangerous for icing.

In one embodiment, not shown, the warning signal is an electrical signal, which is sent to an operator of the wind turbine. In a further embodiment, not shown, the warning signal is an acoustic signal.

4 shows a wind turbine 100 with a protective agent 135 where the protective agent 135 is formed, an icebound zone 130 the wind turbine 100 secure against unauthorized entry. The icicle zone 130 has been determined according to a method according to the first aspect of the invention. The protective agent 135 is a fence in the illustrated embodiment, in other non-illustrated embodiment is the protection means 135 a warning sign, a ditch or a wall.

In the 4 shown wind turbine thus differs from the wind turbine 3 in that no warning signal is triggered if a moving object is within the icing zone 130 the wind turbine is already there, because of the protection 135 can be prevented. The protective agent 135 has an in 4 not shown passage through which specialist personnel, for example in the case of maintenance, can reach the wind turbine.

In one embodiment, not shown, the wind turbine both a protective means, such as a fence, as well as a warning device for triggering a warning signal. As a result, the risk of an accident caused by icefall and / or ice throw for humans and animals can be reduced.

5 shows a wind farm 112 with exemplary three wind turbines 100 a park section that can be the same or different. The three wind turbines 100 are therefore representative of virtually any number of wind turbines of a wind farm 112 with one or more parking sections. The wind turbines 100 put their power, namely in particular the electricity generated via an electric parking network 114 ready. In this case, the currents or outputs of the individual wind turbines are generated 100 added up and usually a transformer 116 is provided which transforms the voltage in the park, then at the at least one common feed point 118 , also commonly referred to as PCC, into the utility grid 120 feed. 5 is only a simplified representation of a wind farm 112 which does not show control, for example, although of course a controller is present. Also, for example, the parking network 114 be designed differently, for example, by a transformer at the output of each wind turbine 100 is present, to name just another embodiment.

The wind farm 112 has a park icebound zone 150 on, with all wind turbines 100 of the wind farm 112 within the park icebound zone 150 lie. The park icebound zone 150 is based on ice-hitting zones 130 the individual wind turbines 100 set, with the icicles 130 each determined by a method for determining an icing zone for wind turbines according to the first aspect of the invention. This can be ice rinks 130 various wind turbines 100 according to different properties of the respective wind turbine 100 also be designed differently.

In the illustrated embodiment, a rectangular shape of the park icebox 150 is utilized. The dimensions of this rectangular shape are based on the icicles 130 of the individual wind turbines 100 established.

In non-illustrated embodiments, the park iceback zone has a round shape, an ellipsoidal shape, a square shape, or a polygonal shape.

In another embodiment, not shown, the park icing zone is formed from a combination of all the icing zones of the respective wind turbines.

The park icebox has in a non-illustrated embodiment, a protective means and another embodiment not shown about a warning device, as in 3 is shown for a wind turbine.

LIST OF REFERENCE NUMBERS

5

Method for determining an icefall and / or ice throw distribution

10, 20, 30, 40, 50

Steps of the method for determining an icefall and / or ice throw distribution

70

deterministically estimated conventional icefall zone

74

outer protection area

78

inner protection area

80

Eiswurfverteilung

90

Area with low ice risk

100

Wind turbine

102

tower

104

gondola

106

rotor

108

rotor blades

110

hub

112

wind farm

114

Park network

116

transformer

118

entry point

120

supply network

130

Eisschlagzone

135

preservative

140

warning device

144

camera system

146

camera

148

lamp

150

Park Eisschlagzone

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011082249 A1 [0006]

Cited non-patent literature

• Cattin, R., A. Heimo, S. Kunz, G. Russi, M. Russi, M. Tiefgraber, S. Schaffner, B.E. Nygaard: Alpine Test Site Guetsch - Meteorological measurements and wind turbine performance analysis. IWAIS XII, Yokohama, October 2007 [0008]
• Baring-Gould et al. (IEA, "Wind Energy Projects in Cold Climates", 2011) [0009, 0050]

Claims (19)

Method (5) for determining an icefall and / or ice throw distribution (80) for a wind energy plant (100), in particular for a single wind energy plant (100) and / or for a collective of a plurality of wind energy plants (100) or a wind farm (112) as a whole, characterized in that - to determine the icefall and / or ice throw distribution (80) are used: plant data of the wind turbine (100), and environmental data of the wind turbine (100), and a Eisstückcharakteristik, and that - the icefall and / or ice throw distribution (80) is determined based on the plant data, the environmental data and the Eisstückcharakteristik via a calculation using a Monte Carlo algorithm. Method according to Claim 1 , wherein the system data, in particular predetermined system data, comprise structural system data. Method according to Claim 1 or 2 wherein the plant data include input and / or measured plant data that varies as part of an operation of the wind turbine. Method according to at least one of the preceding claims, wherein the environment data, in particular variable environment data, temporally unpredictably variable environmental data include. Method according to at least one of the preceding claims, wherein the icefall and / or ice throw distribution (80) is calculated via a multiplicity of icefall and / or ice throw trajectories taking into account a finite extent of corresponding ice pieces. Method according to one of the preceding claims, wherein the icefall and / or ice throw distribution (80) is calculated on the basis of a three-dimensional equation of motion. A method according to any one of the preceding claims, wherein the ice piece characteristic is calculated from a combination of random values for an area of a piece of ice, a mass of a piece of ice and a position of a piece of ice on a rotor blade (108) of the wind turbine (100). Method according to one of the preceding claims, wherein the determination of the icefall and / or ice throw distribution (80) is based on random values for the area and the mass of a piece of ice. The method of any one of the preceding claims, wherein the determination of the icefall and / or ice throw distribution (80) is based on random values for the area to mass ratio A / M of a piece of ice. Method according to one of the preceding claims, wherein the Eisstückcharakteristik based on an ice classification of the location of the wind turbine. The method of at least one of the preceding claims, wherein the ice piece characteristic comprises data selected from the group consisting of: an average weight of ice pieces, an average number of ice pieces on a rotor blade (108) of the wind turbine, a proportion of thrown ice pieces on the rotor blade (108), a residence time of ice pieces on the rotor blade (108). Method according to at least one of the preceding claims, wherein the method further comprises the following steps - Providing the, in particular predetermined, system data of the wind turbine (100); - determining or measuring the environmental data of the wind turbine (100); Setting a plurality of ice piece characteristic random values based, at least in part, on the environmental data; Calculating a plurality of icefall and / or ice trajectories based on the plant data, the environmental data and the plurality of ice pieces characteristic random values; Determining the icefall and / or ice throw distribution (80) from the plurality of icefall and / or ice throw trajectories. The method of at least one of the preceding claims, further comprising capturing weather data averaged over a past period of time to provide the environmental data. Method according to at least one of the preceding claims, wherein furthermore on the basis of the icefall and / or ice throw distribution (80), an iceblogging zone (130) around the wind energy plant (100) is determined. Method for operating a wind energy plant (100), wherein for the wind energy plant (100) an icefall and / or ice throw distribution is determined, in particular continuously determined, according to the method for determining an icefall and / or ice throw distribution for a wind energy plant (100) according to at least one of Claims 1 to 14 wherein, depending on the icefall and / or ice throw distribution, turning off the wind turbine (100) and / or issuing a warning signal is triggered if the probability of an ice throw and / or icefall to an external object exceeds a predetermined limit. A wind turbine (100) having a warning device (140), wherein the warning device (140) is arranged to trigger a warning signal if the probability of an ice throw and / or icefall to an external object by the wind turbine (100) exceeds a predetermined limit, characterized in that the probability of an ice throw and / or ice fall on an external object is determined by a method for determining an icefall and / or ice throw distribution (80) for the wind energy installations (100) according to at least one of Claims 1 to 14 is determined. Wind turbine (100) with a warning device (140) according to Claim 16 wherein the warning device (140) comprises a storage unit, wherein the storage unit is configured to store and output ice rink zone data having information about characteristics of an icebox (130) defined by the icefall and / or ice throw distribution (80). Software with program means comprising a module which is designed to provide a method for determining an icefall and / or ice throw distribution of a wind energy plant via a Monte Carlo algorithm according to at least one of Claims 1 to 14 to control. A wind farm (112) comprising a plurality of wind turbines (100) of one or more parking sections, wherein wind turbines (100) of one or more parking sections are interconnected via at least one common feed point (118) for connection to a utility grid, wherein - the wind farm ( 112) comprises a warning device configured to trigger a warning signal if the probability of an ice throw and / or icefall to an external object by a wind turbine (100) of the wind farm (112) exceeds a predetermined limit, wherein - the probability of an ice throw and or Eisfalls on an external object for each wind turbine of the wind farm each by a method for determining an icefall and / or ice throw distribution (80) according to at least one of Claims 1 to 14 is determined.

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