A method for planning grid connection of a wind farm

Abstract

A method for planning a wind farm (1) at a wind farm site (2) is disclosed Grid information related at least to a region comprising one or more potential wind farm sites (2), the grid information including information regarding grid connecting capability, is collected and stored a database. A potential wind farm site (2) is selected, grid information related to the selected potential wind farm site (2) is retrieved from the database, and grid connecting parameters of the planned wind farm (1) are obtained. At least one available grid connection option (6, 7) for the planned wind farm (1) at the selected potential wind farm site (2) is identified, based on the retrieved grid information and on the obtained grid connecting parameters.

Description

[0001] A METHOD FOR. PLANNING GRID CONNECTION OF A WIND FARM

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a method for planning a wind farm, including planning connection of the wind farm to a power grid.

[0004] BACKGROUND OF THE INVENTION

[0005] When it is intended to erect a new wind farm, various investigations are normally performed in order to evaluate whether or not it will be possible and feasible to erect a wind turbine at a given potential wind farm site. Such investigations may, e.g., include investigations regarding expected wind resources at the potential wind farm site, terrain conditions, expected wake and / or turbulence conditions, noise regulations, etc. Furthermore, the investigations may include a siting process, in which a number of wind turbines are positioned in a suitable manner within the potential wind farm site.

[0006] Accordingly, the investigations performed prior to erecting a wind farm are mainly related to revealing how much energy the planned wind farm will be able to produce, and thereby indicating an expected revenue for the owner of the wind farm. This may be applied as a basis for determining whether or not to actually erect the wind farm.

[0007] However, in order to generate a revenue, it is necessary that it is possible to feed the electrical power produced by the wind farm into the power grid. With the increased fraction of renewable power producers in the power grids and the transition from fossil based power consumption to electrical power consumption, including the increase in the fleet of electrical vehicles, it may not always be possible to connect a new wind farm of a given size to the power grid at a given location. Accordingly, erecting a new wind farm at a given potential wind farm site may in fact not be feasible, even if it appears so from the expected wind resources, etc. DESCRIPTION OF THE INVENTION

[0008] It is an object of embodiments of the invention to provide a method for planning a wind farm at a wind farm site, in which it is ensured that the wind farm can be connected to the power grid.

[0009] The invention provides a method for planning a wind farm at a wind farm site, the method comprising the steps of:

[0010] - collecting grid information related at least to a region comprising one or more potential wind farm sites, the grid information including information regarding grid connecting capability, and storing the collected grid information in a database,

[0011] - selecting a potential wind farm site,

[0012] - retrieving grid information related to the selected potential wind farm site from the database,

[0013] - obtaining grid connecting parameters of the planned wind farm, and

[0014] - identifying at least one available grid connection option for the planned wind farm at the selected potential wind farm site, based on the retrieved grid information and on the obtained grid connecting parameters.

[0015] Thus, the method according to the invention is a method for planning a wind farm at a wind farm site. In the present context the term 'wind farm' should be interpreted to mean a collection of two or more wind turbines arranged within a limited geographical area, i.e. a wind farm site, and which may share various forms of infrastructure, such as access roads, communication network, substations, power electronics, grid connections, etc. Within the context of the present invention, the wind farm has not yet been erected, but is merely in the phase of planning. Accordingly, the method according to the invention forms part of the investigations regarding feasibility, etc., taking place prior to erecting a wind farm. In the method according to the invention, grid information is initially collected and stored in a database. The collected grid information relates at least to a region comprising one or more potential wind farm sites, and it is therefore relevant with regard to planning a wind farm at this or these potential wind farm site(s).

[0016] The collected grid information includes information regarding grid connecting capability, i.e. information regarding the capability of the power grid with related infrastructure to accommodate connection of a new wind farm to the power grid at specified geographical locations, notably at or near geographical locations which may be considered as potential new wind farm sites. Information which may be relevant in this regard includes information regarding position of various infrastructure, such as power lines, substations, etc., capacity of the existing infrastructure, various local specifications of the power grid, etc. This will be described in further detail below.

[0017] Thus, the grid information being collected and stored in the database provides information regarding the capability of the power grid to have new power producers, e.g. in the form of a new wind farm, connected thereto, correlated with geographical position data. Accordingly, the collected and stored grid information may be regarded as georeferenced electrical grid data.

[0018] The grid information may, e.g., be collected from various publicly available sources, such as information published by transmission system operators (TSOs), distribution system operators (DSOs), local authorities, etc.

[0019] Alternatively or additionally, grid information may be collected from proprietary sources.

[0020] The step of collecting grid information may be performed independently of the remaining steps of the method according to the invention which will be described below. For instance, the grid information may be collected and stored in the database well before it has been decided to plan a new wind farm. Alternatively or additionally, relevant grid information may be collected and stored as a part of or immediately before the planning process of a new wind farm. The method according to the invention further comprises selecting a potential wind farm site, i.e. selecting a geographical location where erection of a new wind farm may be considered. The selected potential wind farm site may be a site which has already been the subject of a siting process, in which the available wind resources and terrain conditions have been investigated and evaluated. Positions of the individual wind turbines within the potential wind farm site may also have been picked already. Alternatively, the potential wind farm site may merely be a location being under consideration for a new wind farm, and no detailed investigations regarding wind resources, etc., may have been performed yet. In this case such detailed siting investigations may be postponed until it has been established that it will be possible to connect the planned wind farm to the power grid at the selected potential wind farm site.

[0021] The selected potential wind farm site may form one of a number of candidate wind farm sites. In this case the process described below may be performed for each candidate site, and the most promising site may be selected for further planning of the wind farm.

[0022] Next, grid information related to the selected potential wind farm site is retrieved from the database. Accordingly, the grid information being retrieved relates to the capability of the power grid to have new power sources connected thereto at or near the geographical location of the selected potential wind farm site.

[0023] Furthermore, grid connecting parameters of the planned wind farm are obtained. In the present context the term 'grid connecting parameters' should be interpreted to mean parameters related to the planned wind farm, and which are relevant for determining whether or not the planned wind farm can be connected to a given local part of the power grid. The grid connecting parameters may, e.g., include requirements or specifications, such as rated power output, voltage specifications, etc. This will be described in further detail below.

[0024] Finally, at least one grid connection option for the planned wind farm at the selected potential wind farm site is identified. This is done based on the retrieved grid information and on the obtained grid connecting parameters. In the present context the term 'grid connection option' should be interpreted to mean a workable manner of connecting the planned wind farm to the power grid, at or near the selected potential wind farm site.

[0025] Thus, the at least one grid connection option is identified in a manner which takes into account the capability of the power grid to have new power producers connected thereto, locally at the location of the potential wind farm site, and with due consideration to the requirements of the planned wind farm, in terms of connecting to the power grid. Accordingly, it is ensured that a wind farm with the intended specifications can in fact be connected to the power grid, via one or more of the at least one identified grid connection option, when it has been erected at the potential wind farm site. Thereby it is also ensured that the expected energy production of the wind farm can in fact be absorbed by the power grid, and that the expected revenue can therefore be obtained.

[0026] The grid information may comprise information regarding position of existing substations and / or position of existing power lines.

[0027] According to this embodiment, the grid information being collected and stored in the database, and subsequently applied for identifying available grid connection options, includes information regarding the already existing local infrastructure related to the power grid, in the form of position of existing substations and / or position of existing power lines.

[0028] A substation is a suitable connection point for connecting a new power producer, such as a new wind farm, to the power grid. Therefore, identifying existing substations in the vicinity of the selected potential wind farm site provides a list of possible or potential connection points for the planned wind farm. However, it might be necessary to investigate the substations further, e.g. with regard to available capacity and / or other specifications, before a given nearby substation can be identified as an available grid connection option. This will be described in further detail below.

[0029] Similarly, the position of existing power lines indicates where it may be possible to establish a new connection point to the power grid, e.g. in the form of a new substation. However, also in this case, it might be necessary to investigate the power lines further, e.g. in terms of available capacity, stability, robustness, etc., before a certain position along an existing power line can be identified as an available grid connection option. This will be described in further detail below.

[0030] The grid information may comprise information regarding attributes of existing substations and / or attributes of existing power lines. According to this embodiment, the collected and stored grid information is not merely related to the existence and position of various infrastructure components, such as substations and power lines, but information regarding relevant attributes thereof is also provided. Such attributes may, e.g., provide an indication regarding whether or not the existing infrastructure is in fact in a shape which allows the connection of the planned wind farm.

[0031] The attributes of existing substations and / or attributes of existing power lines may include available connection capacity and / or voltage rating. According to this embodiment, the collected and stored grid information readily provides information regarding the amount of additional energy it will be possible to feed to the power grid via the existing infrastructure, and / or the voltage rating to be matched by a new power source. Comparing this to the specifications of the planned wind farm, it can readily be determined whether or not it is possible to connect the planned wind farm to the power grid, via the existing substations and / or existing power lines. Accordingly, only substations and / or positions along power lines with sufficient available capacity and / or suitable voltage rating are identified as available grid connection options.

[0032] Alternatively or additionally, the attributes of the existing substations and / or existing power lines may include substation name, geographical coordinates, relationship among neighbouring substations, local grid code requirements, fault current levels, etc.

[0033] The grid information may comprise information regarding planned upgrades of existing substations and / or planned upgrades of existing power lines. According to this information, not only the existing grid infrastructure, but also planned upgrades thereof, are taken into account when identifying available grid connection options. This may provide a more accurate picture of the available options for connecting the planned wind farm to the power grid at the future point in time where the erection of the wind farm has been completed.

[0034] Alternatively or additionally, the method may include estimating costs involved with providing necessary upgrades to the existing grid infrastructure, e.g. in the form of new substations, new power lines, increased capacity of existing substations and / or power lines, etc. This could, e.g., be relevant in the case that such costs are to be carried by the contractor erecting the planned wind farm, since, in this case, such costs should be included in the costs of establishing the wind farm, and this may affect the feasibility of the project.

[0035] The step of identifying at least one available grid connection option may comprise identifying the nearest existing substation to the selected potential wind farm site. Selecting the nearest existing substation as a connection point for the planned wind farm allows the wind farm to be connected to the power grid without costs arising from providing new infrastructure, and with a minimal energy loss due to transport from the wind turbines of the wind farm to the point of connection to the power grid. However, since it is a prerequisite that the substation has sufficient available capacity, substations with insufficient capacity may be disregarded, and a substation arranged further away from the selected potential wind farm site, but having sufficient available capacity, may instead be identified as the nearest substation.

[0036] The step of identifying at least one available grid connection option may comprise identifying a suitable position for a new substation. According to this embodiment, at least one of the identified available grid connection options is a suggestion for building a new substation and connecting the planned wind farm to the power grid via the new substation. The identified position of the new substation may, e.g., be immediately adjacent to an existing power line, preferably a power line with sufficient available capacity to allow the wind farm to be connected thereto, for instance at a position along this power line which defines a minimum distance to the selected potential wind farm site.

[0037] Alternatively or additionally, the identified position for the new substation may be a central position of the potential wind farm site, e.g. defining minimal distances to the wind turbines of the wind farm.

[0038] The grid connecting parameters of the planned wind farm may comprise a rated power output level of the planned wind farm. According to this embodiment, the capacity required from the potential grid connection options, in terms of expected power output to be absorbed by the power grid via the grid connection, is taken into account when identifying the available grid connection options. Thus, potential grid connection options with insufficient available capacity may be disregarded.

[0039] Alternatively or additionally, the grid connecting parameters of the planned wind farm may include voltage requirements, frequency requirements, relevant grid network codes, etc.

[0040] The method may further comprise the step of, after selecting a potential wind farm site and prior to retrieving grid information from the database, collecting updated grid information related at least to the selected potential wind farm site, and storing the updated grid information in the database.

[0041] According to this embodiment, once a potential wind farm site has been selected, it is investigated whether or not relevant grid information is available, at least being relevant for the selected potential wind farm site, which is more recent than the previously collected grid information which is currently available in the database. If this is the case, such updated grid information is collected and added to the database, or the outdated grid information in the database is replaced by the updated grid information. Thereby it is ensured that the identification of the at least one available grid connection option is performed on the basis of grid information which is as recent and updated as possible.

[0042] Alternatively or additionally, the grid information in the database may be updated at regular time intervals, e.g. depending on how often the various publicly available sources of the grid information are updated. The method may further comprise the step of designing a layout of the planned wind farm, including positioning a plurality of wind turbines within one or more potential wind farm sites.

[0043] According to this embodiment, a usual siting process is further performed, e.g. including investigating wind conditions and terrain conditions at the potential wind farm site and selecting suitable positions for the wind turbines within the potential wind farm site. The siting process may be performed before or after the steps described above, leading to the identification of at least one available grid connection option, or the two processes may be performed essentially simultaneously, e.g. forming part of one single siting process, which takes the grid connection options into account on an equal footing with the available wind resources, etc.

[0044] The method may further comprise the step of erecting the wind farm at the selected potential wind farm site and connecting the wind farm to the power grid via one or more of the at least one identified available grid connection options.

[0045] According to this embodiment, the wind farm is actually erected and connected to the power grid, following the planning and investigations described above.

[0046] BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The invention will now be described in further detail with reference to the accompanying drawings in which

[0048] Figs. 1-3 illustrate various identified available grid connection options resulting from a method according to an embodiment of the invention, and

[0049] Fig. 4 is a flow chart illustrating a method according to an embodiment of the invention. DETAILED DESCRIPTION OF THE DRAWINGS

[0050] Figs. 1-3 illustrate a map with a planned wind farm 1 at a selected potential wind farm site 2. The map further shows existing power lines, in the form of 110 kV power lines 3, 220 kV power lines 4 and 400 kV power lines 5.

[0051] Two existing substations 6a and 6b are shown. Existing substation 6a is closer to the selected potential wind farm site 2 than existing substation 6b. However, the available capacity of existing substation 6b is higher than the available capacity of existing substation 6a.

[0052] Furthermore, a suitable position for a new substation 7 is indicated. The position of the new substation 7 is such that it is arranged immediately adjacent to an existing 220 kV power line 4, thereby allowing the new substation 7 to connect directly to this power line 4, and as close as possible to the selected potential wind farm site 2 and the wind turbines of the planned wind farm 1.

[0053] In Fig. 1, existing substation 6a is identified as an available grid connection option for the planned wind farm 1. This is relevant since substation 6a is the existing substation being located closest to the selected potential wind farm site 2. Thus, connecting power lines 8 required in order to connect the wind turbines of the planned wind farm 1 to the existing substation 6a are indicated.

[0054] In Fig. 2, existing substation 6b is identified as an available grid connection option for the planned wind farm 1, even though it is located further away from the selected potential wind farm site 2 than existing substation 6a. This may, however, still be relevant, e.g. because the available capacity of existing substation 6b is higher than the available capacity of existing substation 6a, and the available capacity of existing substation 6a may even be considered insufficient to accommodate the expected energy production of the planned wind farm 1. Accordingly, existing substation 6b may be the best choice for connecting the planned wind farm 1 to the power grid, despite the longer distance as compared to existing substation 6a. Connecting power lines 8 required in order to connect the wind turbines of the planned wind farm 1 to the existing substation 6b are indicated. In Fig. 3, new substation 7 is identified as an available grid connection option for the planned wind farm 1. It can be seen that the position of the new substation 7 is chosen immediately adjacent to an existing 220 kV power line 4, and at a position along this power line 4 which results in minimal distances between the wind turbines of the planned wind farm 1 and the new substation 7. Thus, losses due to energy transfer in the connecting power lines 8 are minimised.

[0055] Selecting the new substation 7 as the connection point for the planned wind farm 1 to the power grid may, e.g., be relevant in the case that the existing nearby substations 6a, 6b have insufficient available capacity to fully accommodate the expected energy production of the planned wind farm 1, and / or if it is estimated that the costs involved with establishing the new substation 7 are compensated by reduced losses due to the shorter distance to the new substation 7 and / or by less curtailment operation due to higher capacity at the substation 7.

[0056] The grid connection options illustrated in Figs. 1-3 may be presented to a user as alternatives from which the user may choose. As an alternative, only the grid connection option which appears to be the best option may be presented to the user. As another alternative, the option illustrated in Fig. 3 may be presented along with one of the options illustrated in Figs. 1 and 2, i.e. establishing a new substation 7 may be presented as an alternative to using an existing substation 6a, 6b, and the existing substation 6a, 6b which appears to be the best option may be suggested.

[0057] Fig. 4 is a flow chart illustrating a method according to an embodiment of the invention. The process is started at step 9. At step 10, grid information is collected and stored in a database. The grid information includes information regarding grid connecting capability, at least within a region comprising one or more potential wind farm sites. For instance, the grid information may include information regarding existing power grid infrastructure, such as existing substations and / or existing power lines, as well as relevant attributes regarding the existing infrastructure, such as available capacity, voltage rating, etc. At step 11, a potential wind farm site for a planned wind farm is selected, and at step 12, grid information related to the selected potential wind farm site is retrieved from the database. Furthermore, grid connecting parameters of the planned wind farm are obtained, e.g. in the form of parameters specifying requirements of the planned wind farm in terms of connecting to the power grid.

[0058] At step 13, at least one available grid connection option for the planned wind farm at the potential wind farm site is identified. This is done on the basis of the retrieved grid information, as well as based on the obtained grid connecting parameters of the planned wind farm. Thus, it is ensured that the planned wind farm, with the expected specifications, can in fact be connected to the power grid via the identified available grid connection options. The available grid connection options could, e.g., be in the form of one or more existing substations and / or suggested positions for building one or more new substations.

[0059] At step 14 it is investigated whether or not there are further potential wind farm sites for the planned wind farm that should be investigated. If this is the case, the process is returned to step 11, where the next potential wind farm site is selected, and the steps described above are repeated for the newly selected potential wind farm site.

[0060] In the case that step 14 reveals that there are no further potential wind farm sites, the process is forwarded to step 15, where a wind farm site and a grid connection option are selected. The wind farm may then be erected at the selected wind farm site and connected to the power grid via the selected grid connection option.

Claims

CLAIMS1. A method for planning a wind farm (1) at a wind farm site (2), the method comprising the steps of:- collecting grid information related at least to a region comprising one or more potential wind farm sites (2), the grid information including information regarding grid connecting capability, and storing the collected grid information in a database,- selecting a potential wind farm site (2),- retrieving grid information related to the selected potential wind farm site (2) from the database,- obtaining grid connecting parameters of the planned wind farm (1), and- identifying at least one available grid connection option (6, 7) for the planned wind farm (1) at the selected potential wind farm site (2), based on the retrieved grid information and on the obtained grid connecting parameters.

2. A method according to claim 1, wherein the grid information comprises information regarding position of existing substations (6) and / or position of existing power lines (3, 4, 5).

3. A method according to claim 1 or 2, wherein the grid information comprises information regarding attributes of existing substations (6) and / or attributes of existing power lines (3, 4, 5).

4. A method according to claim 3, wherein the attributes of existing substations (6) and / or attributes of existing power lines (3, 4, 5) include available connection capacity and / or voltage rating.

5. A method according to any of the preceding claims, wherein the grid information comprises information regarding planned upgrades of existing substations (6) and / or planned upgrades of existing power lines (3, 4, 5).

6. A method according to any of the preceding claims, wherein the step of identifying at least one available grid connection option comprises identifying the nearest existing substation (6) to the selected potential wind farm site (2).

7. A method according to any of the preceding claims, wherein the step of identifying at least one available grid connection option comprises identifying a suitable position for a new substation (7).

8. A method according to any of the preceding claims, wherein the grid connecting parameters of the planned wind farm (1) comprise a rated power output level of the planned wind farm (1).

9. A method according to any of the preceding claims, further comprising the step of, after selecting a potential wind farm site (2) and prior to retrieving grid information from the database, collecting updated grid information related at least to the selected potential wind farm site (2), and storing the updated grid information in the database.

10. A method according to any of the preceding claims, further comprising the step of designing a layout of the planned wind farm (1), including positioning a plurality of wind turbines within one or more potential wind farm sites (2).

11. A method according to any of the preceding claims, further comprising the step of erecting the wind farm (1) at the selected potential wind farm site (2) and connecting the wind farm (1) to the power grid via one or more of the at least one identified available grid connection options (6, 7).

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