Method for planning grid connection of wind farm

Abstract

A method for planning a wind farm (1) at a wind farm site (2) is disclosed. Grid information relating at least to an area comprising one or more potential wind farm sites (2) is collected, said grid information comprising information about grid connectivity, and the collected grid information is stored in a database. A potential wind farm site (2) is selected, power grid information related to the selected potential wind farm site (2) is retrieved from a database, and power grid connection parameters of the planned wind farm (1) are obtained. Based on the retrieved grid information and the acquired grid connection parameters, 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.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for planning a wind farm, comprising planning a connection of the wind farm to an electrical grid. BACKGROUND

[0002] When a new wind farm is intended to be established, various investigations are usually carried out to assess whether it is possible and feasible to build wind turbines at a given potential wind farm site. For example, such investigations can include investigations regarding expected wind resources, terrain conditions, expected wake and / or turbulence conditions, noise regulations, etc. at the potential wind farm site. Furthermore, the investigations can include a siting process in which a number of wind turbines are positioned in a suitable manner within the potential wind farm site.

[0003] Hence, the investigations carried out before a wind farm is built mainly involve revealing how much energy the planned wind farm will be able to produce, thereby indicating expected revenues for the wind farm owner. This can be used as a basis for deciding whether to actually build the wind farm or not.

[0004] However, in order to produce revenues, it must be possible to feed the electricity produced by the wind farm into an electrical grid. As the proportion of renewable energy producers in the electrical grid increases, and as there is a shift from fossil-based energy consumption to electricity consumption, including an increase in the number of electric vehicles, it can not always be feasible to connect a new wind farm of a given size to the electrical grid at a given location. Hence, even if it is feasible from an expected wind resource, etc. perspective, it can not actually be feasible to build a new wind farm at a given potential wind farm site. SUMMARY

[0005] It is an object of embodiments of the present invention to provide a method for planning a wind farm at a wind farm site, in which method it is ensured that the wind farm is able to be connected to an electrical grid (or power grid).

[0006] The present invention provides a method for planning a wind farm at a wind farm site, the method comprising the steps of: collecting electrical grid information related to at least an area comprising one or more potential wind farm sites, the electrical grid information comprising information about electrical grid connection capabilities, and storing the collected electrical grid information in a database, selecting a potential wind farm site, retrieving electrical grid information related to the selected potential wind farm site from the database, obtaining electrical grid connection parameters for the planned wind farm, and identifying at least one available grid connection option for the planned wind farm at the selected potential wind farm site based on the retrieved electrical grid information and the obtained electrical grid connection parameters.

[0007] Thus, the method according to the present application is a method for planning a wind farm at a wind farm site. In this context, the term "wind farm" is to be interpreted to mean a collection of two or more wind turbines arranged within a limited geographical area, i.e. the wind farm site, and these wind turbines can share various forms of infrastructure, such as access roads, communication networks, transformer stations, power electronics, grid connections, etc. In the context of the present application, the wind farm is not yet established, but only in the planning phase. Thus, the method according to the present application constitutes part of the investigation into the feasibility, etc. that is carried out before the wind farm is built.

[0008] In the method according to the present application, grid information is first collected and stored in a database. The collected grid information is related to at least an area comprising one or more potential wind farm sites, and thus it is relevant for planning a wind farm at these potential wind farm sites.

[0009] The collected grid information comprises information about grid connection capabilities, i.e. information about the ability of the grid and related infrastructure to accommodate a new wind farm connection to the grid at a specified geographical location, in particular at or near a geographical location that can be considered a potential new wind farm site. Information that can be relevant in this respect includes information about the location of various infrastructure, such as power lines, transformer stations, etc., the capacity of existing infrastructure, various local specifications of the grid, etc. This will be described in further detail below.

[0010] Thus, the grid information that is collected and stored in the database provides information about the ability of the grid to connect a new power producer, e.g. in the form of a new wind farm, to it, and this information is associated with geographical location data. Thus, the collected and stored grid information can be considered geographical reference grid data.

[0011] The grid information can be collected from various publicly available sources, such as information published by the Transmission System Operator (TSO), the Distribution System Operator (DSO), local authorities, etc. Alternatively or additionally, the grid information can be collected from proprietary sources.

[0012] The step of collecting grid information can be performed independently of the remaining steps of the present application that will be described below. For example, the grid information can be collected and stored in the database long before it is decided to plan a new wind farm. Alternatively or additionally, the relevant grid information can be collected and stored during or immediately prior to the new wind farm planning process.

[0013] The method according to the present application also comprises selecting a potential wind farm site, i.e. selecting a geographical location which can be considered for building a new wind farm. The selected potential wind farm site can be a site which has already been through a siting process, in which the available wind resources and terrain conditions have been investigated and assessed. The locations of individual wind turbines within the potential wind farm site can also have been selected. Alternatively, the potential wind farm site can merely be a location which is being considered for a new wind farm, and can not yet have been subject to detailed investigations regarding wind resources etc. In this case, such detailed siting investigations can be deferred until it has been determined that the planned wind farm can be connected to the grid at the selected potential wind farm site.

[0014] The selected potential wind farm site can constitute one of a plurality of candidate wind farm sites. In this case, the process described below can be performed for each candidate site, and the most promising site can be selected for further planning of a wind farm.

[0015] Next, grid information relating to the selected potential wind farm site is retrieved from a database. The retrieved grid information thus relates to the ability to connect a new power source to the grid at or near the geographical location of the selected potential wind farm site.

[0016] Furthermore, grid connection parameters for the planned wind farm are obtained. In this context, the term "grid connection parameters" is to be interpreted as meaning parameters which are relevant in connection with the planned wind farm and which are relevant for determining whether the planned wind farm can be connected to a given local part of the grid. The grid connection parameters can comprise, for example, requirements or specifications, e.g. rated power output, voltage specifications etc. This will be described in further detail below.

[0017] Finally, at least one grid-connection option for the planned wind farm at the selected potential wind farm site is identified. This is done on the basis of the retrieved grid information and the obtained grid connection parameters.

[0018] In this context, the term "grid-connection option" is to be interpreted as meaning a feasible way of connecting the planned wind farm to the grid at or near the selected potential wind farm site.

[0019] The manner in which the at least one grid-connection option is identified thus takes into account the ability of the grid at the local location of the potential wind farm site to connect a new power producer thereto, and takes due account of the requirements of the planned wind farm in terms of connection to the grid. It is thus ensured that a wind farm having the expected specifications can in fact be connected to the grid via one or more of the identified at least one grid-connection option after having been built at the potential wind farm site. It is thereby also ensured that the expected energy production of the wind farm can in fact be absorbed by the grid, and that the expected revenues can thus be obtained.

[0020] The grid information can comprise information about the location of existing substations and / or the location of existing power lines.

[0021] According to this embodiment, the grid information that is collected and stored in the database and later used for identifying available grid connection options comprises information about the existing local infrastructure of the grid in the form of the location of existing substations and / or the location of existing power lines.

[0022] A substation is a suitable connection point for connecting a new power producer, e.g. a new wind farm, to the grid. Thus, identifying existing substations in the vicinity of a selected potential wind farm site provides a list of possible or potential connection points for the planned wind farm. However, it can be necessary to further investigate a given nearby substation before identifying it as an available grid connection option, e.g. with respect to available capacity and / or other specifications. This will be described in further detail below.

[0023] Similarly, the location of existing power lines indicates where a new connection point to the grid, e.g. in the form of a new substation, can be established. However, also in this case, it can be necessary to further investigate a particular location along an existing power line before identifying it as an available grid connection option, e.g. with respect to available capacity, stability, robustness, etc. This will be described in further detail below.

[0024] The grid information can comprise information about the properties of existing substations and / or the properties of existing power lines. According to this embodiment, the collected and stored grid information not only relates to the existence and location of various infrastructure components, e.g. substations and power lines, but also provides information about their related properties. For example, such properties can indicate whether an existing infrastructure is actually in a state that allows connecting a planned wind farm.

[0025] The properties of existing substations and / or the properties of existing power lines can comprise available connection capacity and / or voltage rating. According to this embodiment, the collected and stored grid information directly provides information about the amount of additional energy that can be fed into the grid via existing infrastructure and / or the voltage rating that needs to be matched by a new power source. Comparing this with the specifications of a planned wind farm, it can be easily determined whether it is possible to connect the planned wind farm to the grid via an existing substation and / or an existing power line. Thus, only substations and / or locations along power lines are identified as available grid connection options that have sufficient available capacity and / or a suitable voltage rating.

[0026] Alternatively or additionally, the properties of existing substations and / or existing power lines can comprise substation names, geographic coordinates, relationships between neighboring substations, local grid specification requirements, fault current levels, etc.

[0027] The grid information can comprise information about planned upgrades of existing substations and / or planned upgrades of existing power lines. In light of this information, not only the existing grid infrastructure, but also its planned upgrades are taken into account when identifying available grid connection options. This can provide a more accurate picture about available options to connect the planned wind farm to the grid at a future point in time, i.e. when the wind farm is built.

[0028] Alternatively or additionally, the method can comprise estimating costs involved in necessary upgrades to the existing grid infrastructure, e.g. in the form of new substations, new power lines, increasing the capacity of existing substations and / or power lines, etc. This can be relevant, e.g. in case the contractor of the planned wind farm is required to bear such costs, because in this case such costs should be accounted for in the cost of establishing the wind farm and this can affect the feasibility of the project.

[0029] The step of identifying at least one available grid connection option can comprise identifying the existing substation that is closest to the selected potential wind farm site. Selecting the closest existing substation as the connection point for the planned wind farm can connect the wind farm to the grid without incurring the cost of providing new infrastructure and with minimal energy losses due to transmission from the wind turbines of the wind farm to the connection point of the grid. However, since the prerequisite is that the substation has sufficient available capacity, a substation with insufficient capacity can be disregarded and a substation that is arranged further away from the selected potential wind farm site but has sufficient available capacity can be identified as the closest substation.

[0030] The step of identifying at least one available grid connection option can comprise identifying a suitable location for a new substation. According to this embodiment, at least one of the identified available grid connection options is a proposal to build a new substation and to connect the planned wind farm to the grid via the new substation. The location of the identified new substation can be, e.g., next to an existing power line, preferably a power line that has sufficient available capacity to allow the wind farm to be connected thereto, e.g. at a location along the power line that is closest to the selected potential wind farm site. Alternatively or additionally, the location of the identified new substation can be a central location of the potential wind farm site, e.g. defined by a minimum distance to the wind turbines of the wind farm.

[0031] The grid connection parameters of the planned wind farm can comprise a rated power output level of the planned wind farm. According to this embodiment, the capacity requirements of potential grid connection options in terms of expected power output, i.e. the power to be absorbed by the grid via the grid connection, are taken into account when identifying available grid connection options. Therefore, potential grid connection options with insufficient available capacity can be disregarded.

[0032] Alternatively or additionally, the planned grid connection parameters of the wind farm can comprise voltage requirements, frequency requirements, relevant grid codes, etc.

[0033] The method can further comprise, after selection of a potential wind farm site and prior to retrieval of grid information from the database, the step of collecting up-to-date grid information relating at least to the selected potential wind farm site and storing the up-to-date grid information in the database.

[0034] According to this embodiment, upon selection of a potential wind farm site, it is investigated whether relevant grid information exists which is more up-to-date than the previously collected grid information in the current database and which relates at least to the selected potential wind farm site. If such a case exists, such up-to-date grid information is collected and added to the database or the outdated grid information in the database is replaced by the up-to-date grid information. Thereby it is ensured that the identification of the at least one available grid connection option is performed on the basis of the most up-to-date grid information available.

[0035] Alternatively or additionally, the grid information in the database can be updated at regular time intervals, e.g. depending on the update frequency of various publicly available sources of grid information.

[0036] The method can further comprise the step of designing a layout of the planned wind farm, which step comprises positioning a plurality of wind turbines within one or more potential wind farm sites.

[0037] According to this embodiment, a conventional siting process is performed, e.g. comprising investigating the wind conditions and terrain conditions at the potential wind farm sites and selecting suitable locations for wind turbines within the potential wind farm sites. The siting process can be performed before or after the above-mentioned step leading to the identification of the at least one available grid connection option, or both processes can be performed substantially simultaneously, e.g. forming part of a single siting process which considers grid connection options on equal footing with available wind resources, etc.

[0038] The method can further comprise the step of constructing a wind farm at the selected potential wind farm site and connecting the wind farm to the grid via one or more of the identified at least one available grid connection option.

[0039] According to this embodiment, after following the above-mentioned planning and investigation, the wind farm is actually constructed and connected to the grid. BRIEF DESCRIPTION OF DRAWINGS

[0040] The application will be described in further detail below with reference to the drawings in which, Figures 1 to 3 various identified available grid connection options resulting from the method according to an embodiment of the application are shown; and Figure 4This is a flowchart illustrating a method according to an embodiment of the present invention. Detailed Implementation

[0041] Figures 1 to 3 A map showing the planned wind farm 1 located at the selected potential wind farm site 2 is displayed. The map also shows the existing power lines, presented as 110 kV power line 3, 220 kV power line 4, and 400 kV power line 5.

[0042] 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 greater than that of existing substation 6a.

[0043] Furthermore, a suitable location for the new substation 7 is shown. The location of the new substation 7 is set to be adjacent to the existing 220kV power line 4, thereby allowing the new substation 7 to be directly connected to the power line 4, and as close as possible to the wind turbines of the selected potential wind farm site 2 and the planned wind farm 1.

[0044] exist Figure 1 In this diagram, existing substation 6a is identified as a available grid connection option for the planned wind farm 1. This is significant because substation 6a is the existing substation located closest to the selected potential wind farm site 2. Therefore, the connecting power line 8 required to connect the wind turbines of the planned wind farm 1 to existing substation 6a is shown.

[0045] exist Figure 2 In this diagram, existing substation 6b is identified as a available grid connection option for the planned wind farm 1, despite being farther from the selected potential wind farm site 2 than existing substation 6a. However, this still makes sense, for example, because the available capacity of existing substation 6b is greater than that of existing substation 6a, and the available capacity of existing substation 6a may even be considered insufficient to accommodate the expected energy output of the planned wind farm 1. Therefore, despite the greater distance, existing substation 6b may be the optimal choice for connecting the planned wind farm 1 to the grid. The required power line 8 for connecting the wind turbines of the planned wind farm 1 to existing substation 6b is shown.

[0046] exist Figure 3 In this study, the new substation 7 is identified as a viable grid connection option for the planned wind farm 1. It can be seen that the location of the new substation 7 is chosen to be adjacent to the existing 220kV power line 4, and along the power line 4, at a location that minimizes the distance between the wind turbines of the planned wind farm 1 and the new substation 7. Therefore, energy transmission losses in the connection to the power line 8 are minimized.

[0047] Choosing a new substation 7 as the connection point between the planned wind farm 1 and the grid may be meaningful, for example, if the available capacity of nearby existing substations 6a and 6b is insufficient to fully accommodate the expected energy output of the planned wind farm 1, and / or if estimates indicate that the costs involved in building the new substation 7 are offset by reduced losses due to the shorter distance to the new substation 7 and / or reduced curtailment operations due to the higher capacity at substation 7.

[0048] Figures 1 to 3 The grid connection options shown can be presented to the user as alternatives for selection. Alternatively, only the grid connection options that appear to be the best choice can be presented to the user. As another alternative, Figure 3 The options shown can be used with Figure 1 and Figure 2 One of the options shown is presented together, namely, that building a new substation 7 can be presented as an alternative to using existing substations 6a and 6b, and existing substations 6a and 6b may be suggested as the best option.

[0049] Figure 4 This is a flowchart illustrating a method according to an embodiment of the present invention. The process begins at step 9. In step 10, grid information is collected and stored in a database. The grid information includes information about grid connectivity, at least in areas including one or more potential wind farm sites. For example, the grid information may include information about existing grid infrastructure, such as existing substations and / or existing power lines, and relevant attributes of the existing infrastructure, such as available capacity, voltage ratings, etc.

[0050] In step 11, a potential wind farm site is selected for the planned wind farm, and in step 12, grid information related to the selected potential wind farm site is retrieved from the database. Furthermore, grid connection parameters for the planned wind farm are obtained, for example, in the form of parameters specifying the grid connection requirements of the planned wind farm.

[0051] In 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 based on retrieved grid information and the obtained grid connection parameters of the planned wind farm. This ensures that the planned wind farm with the intended specifications can indeed be connected to the grid via the identified available grid connection option. Available grid connection options may take the form, for example, one or more existing substations and / or suggested locations for constructing one or more new substations.

[0052] In step 14, an investigation is conducted to determine if there are any other potential wind farm sites that should be investigated for the planned wind farm. If so, the process returns to step 11, where the next potential wind farm site is selected, and the above steps are repeated for the newly selected potential wind farm site.

[0053] If step 14 reveals that no more potential wind farm sites are available, the process proceeds to step 15, where a wind farm site and grid connection options are selected. A wind farm can then be built at the selected site and connected to the grid via the chosen grid connection option.

Claims

1. A method for planning a wind farm (1) at a wind farm site (2), the method comprising the following steps: - Collect grid information relating to at least the area including one or more potential wind farm sites (2), including information on grid connectivity, and store the collected grid information in a database. - Select potential wind farm sites (2). - Retrieve grid information related to the selected potential wind farm site (2) from the database. - Obtain the grid connection parameters of the planned wind farm (1), and -Based on the retrieved grid information and the obtained grid connection parameters, identify at least one available grid connection option (6, 7) for the planned wind farm (1) at the selected potential wind farm site (2).

2. The method according to claim 1, wherein, The power grid information includes information about the location of existing substations (6) and / or existing power lines (3, 4, 5).

3. The method according to claim 1 or 2, wherein, The power grid information includes information about the properties of existing substations (6) and / or existing power lines (3, 4, 5).

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

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

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

7. The method according to any one of the preceding claims, wherein, The steps for identifying at least one available grid connection option include identifying a suitable location for the new substation (7).

8. The method according to any one of the preceding claims, wherein, The grid connection parameters of the planned wind farm (1) include the rated power output level of the planned wind farm (1).

9. The method according to any one of the preceding claims further includes the step of collecting, at least the latest grid information related to the selected potential wind farm site (2) and storing the latest grid information in the database after selecting the potential wind farm site (2) and before retrieving grid information from the database.

10. The method according to any one of the preceding claims further includes the step of designing the layout of the planned wind farm (1), the step of which includes locating a plurality of wind turbines within one or more potential wind farm sites (2).

11. The method according to any one of the preceding claims further includes the steps of constructing a 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 at least one of the identified available grid connection options (6, 7).

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