Method and device for configuring capacity of phase modifier in wind farm

Abstract

The embodiment of the present specification provides a method and device for configuring the capacity of a phase modifier in a wind farm, wherein the method comprises: obtaining system parameters of the wind farm; calculating a wind turbine terminal short-circuit ratio based on the system parameters; when the wind turbine terminal short-circuit ratio is less than a strong system short-circuit ratio, calculating a required configuration parameter of the capacity of the phase modifier in the wind farm according to a difference between an expected short-circuit ratio and the wind turbine terminal short-circuit ratio. The embodiment of the present specification solves the transient overvoltage problem and the power output limitation problem of the wind farm in the prior art, provides a capacity reference for configuring the phase modifier in the wind farm, and can improve the system short-circuit ratio and the power output capability of the wind farm connected to the grid.

Description

Technical Field

[0001] This document relates to the field of computer technology, and in particular to a method and apparatus for configuring the capacity of synchronous condensers in a wind farm. Background Technology

[0002] With the large-scale grid connection of new energy sources such as wind power, the way power electronic devices are connected to the grid is changing the traditional power system structure. The increasing proportion of renewable energy in the power system has brought a series of new challenges to the safe and stable operation of the power system, such as low grid strength and transient voltage faults. This further limits the transmission capacity of wind farms, preventing them from fully utilizing their power generation potential.

[0003] To address the aforementioned issues, the industry widely employs the configuration of reactive power devices (RPMs) to improve system stability, including capacitor banks and static synchronous compensators (STATCOMs). These RPMs can absorb or provide reactive power, increasing short-circuit capacity and thus alleviating some problems to a certain extent. For example, existing technologies provide a method for configuring synchronous condensers, calculating the net revenue of wind farms and photovoltaic power plants to determine the optimal total number of synchronous condensers, but without analyzing the underlying mechanisms of the system after configuring RPMs. Another existing technology provides a solution that studies the balance of synchronous condenser allocation from the perspective of overall planning of the new energy system and the inter-station ratio of new energy plants, but it does not address the issue of synchronous condenser capacity configuration within wind farms or its impact on wind power transmission capacity.

[0004] In summary, while existing technologies describe ways to improve the power transmission capacity of renewable energy power plants, increase the system short-circuit ratio and grid voltage support capacity, and enhance the stability of renewable energy units when connected to the grid, they do not analyze or evaluate the system output before and after configuring synchronous condensers within the wind farm. Therefore, there is an urgent need for a method and device for configuring synchronous condenser capacity within wind farms to improve the grid-connected power transmission capacity of wind farms. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for configuring the capacity of synchronous condensers in a wind farm, in order to solve the above-mentioned problems in the prior art.

[0006] This invention provides a method for configuring the capacity of a synchronous condenser in a wind farm, comprising:

[0007] Obtain system parameters of the wind farm;

[0008] Based on the system parameters, the short-circuit ratio at the wind turbine terminal is calculated. When the short-circuit ratio at the wind turbine terminal is less than the short-circuit ratio of the strong system, the required synchronous condenser capacity parameters for the wind farm are calculated based on the difference between the expected short-circuit ratio and the short-circuit ratio at the wind turbine terminal.

[0009] This invention provides a device for configuring the capacity of a synchronous condenser in a wind farm, comprising:

[0010] The acquisition module is used to acquire system parameters of the wind farm;

[0011] The configuration module is used to calculate the short-circuit ratio at the wind turbine terminal based on the system parameters. When the short-circuit ratio at the wind turbine terminal is less than the short-circuit ratio of the strong system, the module calculates the synchronous condenser capacity parameters that need to be configured at the wind farm based on the difference between the expected short-circuit ratio and the short-circuit ratio at the wind turbine terminal.

[0012] This invention also provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the above-described method for configuring the capacity of a synchronous condenser in a wind farm.

[0013] The embodiments of the present invention solve the problems of transient overvoltage and power output limitation of wind farms in the prior art, provide a capacity reference for configuring synchronous condensers in wind farms, and can improve the system short-circuit ratio and enhance the grid-connected power output capability of wind farms with synchronous condensers. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of the method for configuring the capacity of the synchronous condenser in a wind farm according to an embodiment of the present invention;

[0016] Figure 2 This is a detailed flowchart of the method for configuring the capacity of a single grid-connected wind farm using a synchronous condenser, according to an embodiment of the present invention.

[0017] Figure 3 This is a structural diagram of a wind farm grid connection system according to an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram comparing the power output of a wind farm before and after the introduction of SC in an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of a single grid-connected wind farm power transmission capacity configuration device according to an embodiment of the present invention;

[0020] Figure 6 This is a schematic diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0022] Method Implementation Examples

[0023] According to embodiments of the present invention, a method for configuring the capacity of synchronous condensers within a wind farm is provided. Figure 1 This is a flowchart of the wind farm in-situ synchronous condenser capacity configuration method according to an embodiment of the present invention, such as... Figure 1 As shown, the method for configuring the capacity of synchronous condensers in a wind farm according to an embodiment of the present invention specifically includes:

[0024] Step S101: Obtain the system parameters of the wind farm; specifically including:

[0025] Obtain the network topology and parameters of a wind farm, the installed capacity and number of wind farm turbines, reactive power compensation configuration information, as well as the main transformer parameters and equivalent parameters of the external power grid.

[0026] Step S102: Based on the system parameters, calculate the short-circuit ratio at the wind turbine terminal. When the short-circuit ratio at the wind turbine terminal is less than the short-circuit ratio of the main system, calculate the required synchronous condenser capacity parameters for the wind farm based on the difference between the desired short-circuit ratio and the short-circuit ratio at the wind turbine terminal. Specifically, this includes:

[0027] Based on the system parameters, the impedance values ​​of the power grid, high-voltage transmission lines, main transformer, SVG, box-type substation, and wind turbine-side transmission line section are calculated.

[0028] Based on the impedance value and the short-circuit ratio formula, the short-circuit ratio at the computer end and the short-circuit ratio of the reactive power equipment in the original system configuration;

[0029] When the short-circuit ratio at the turbine terminal is less than the short-circuit ratio of the strong system, the difference between the expected short-circuit ratio and the short-circuit ratio at the turbine terminal plus the short-circuit ratio of the original system reactive equipment is obtained.

[0030] Calculate the impedance values ​​of the components on the parallel-connected side of the synchronous condenser, and using the short-circuit ratio formula, calculate the required synchronous condenser capacity from the short-circuit ratio difference. Specifically, the components considered on the parallel-connected side of the synchronous condenser include: a step-up transformer and the synchronous condenser. Specifically:

[0031] Calculate the per-unit impedance value of the synchronous condenser according to Formula 1:

[0032]

[0033] Where, X″ d To adjust the camera impedance value; S b For short-circuit capacity; S SC Adjust the camera's capacity as required;

[0034] Based on Formula 2 and the short-circuit ratio formula, the synchronous condenser capacity S can be calculated. SC :

[0035]

[0036] Where, X″ d To adjust the camera impedance value; S b P is the short-circuit capacity; ΔSCR is the difference in short-circuit ratio that the system needs to compensate for; max S represents the maximum power of the fan. b Short-circuit capacity; This refers to the per-unit impedance value of the transformer on the camera side.

[0037] To verify the power transmission capacity of a single grid-connected wind farm with a synchronous condenser, the technical solution of this embodiment of the invention further includes: establishing a wind farm grid access model, simulating grid fault conditions at the PCC point based on the synchronous condenser parameters, and verifying whether the terminal voltage of the wind turbine does not disconnect from the grid when the wind turbine is generating power at full power, thereby determining the improvement of the wind farm's power transmission capacity.

[0038] As can be seen from the above embodiments, compared with the prior art, the beneficial effects of the ten embodiments of the present invention are as follows:

[0039] (1) By configuring a synchronous condenser for a wind farm, the reactive power regulation capability of the system can be effectively enhanced, the stability of the power grid in the face of disturbances can be improved, and the risk of system collapse can be reduced. In particular, when the power grid at the sending end of the system fails, the synchronous condenser can quickly absorb the large amount of surplus reactive power generated by the reactive power compensation of SVG, and effectively suppress the problem of transient overvoltage.

[0040] (2) The embodiments of the present invention can calculate the minimum capacity of the synchronous condenser that the system needs to be configured from the known parameters of the system, and the calculation method is clear, simple and easy to implement;

[0041] (3) The method verification of the present invention relies on SIMULINK for simulation. In the original weak grid system, the wind farm cannot generate full power and the power needs to be limited to about 60% to operate stably. However, after configuring a synchronous condenser of a certain capacity using the method of the present invention, the system becomes a strong system, and the wind farm can generate full power at this time.

[0042] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] like Figure 2 As shown, the technical solution of this embodiment of the invention specifically includes the following steps:

[0044] The required reference capacity of the synchronous condenser to be configured in the system is calculated based on the known parameters of the system, specifically including the following steps:

[0045] Step S1: Obtain the network topology and parameters of the wind farm system, the installed capacity and number of wind farm turbines, the reactive power compensation configuration, the main transformer parameters, and the equivalent parameters of the external power grid;

[0046] Step S2: Calculate the short-circuit ratio at the wind turbine terminals and compare it with the short-circuit ratio of the strong system.

[0047] First, calculate the short-circuit ratio of the low-voltage side system of the wind turbine, which mainly includes the impedance calculation of the power grid system, high-voltage transmission lines, and transformer components:

[0048] Calculate impedance:

[0049] X=2πfL(1)

[0050] In the formula, f is the system frequency; L is the inductance value;

[0051] Calculate the per-unit value of impedance:

[0052]

[0053] In the formula, S b For short-circuit capacity; U b The reference voltage;

[0054] The sum of the per-unit values ​​of the equivalent impedance of the system can be obtained through calculation.

[0055] Secondly, calculate the system short-circuit ratio; the short-circuit ratio formula.

[0056]

[0057] In the formula, K SCR Indicates the short-circuit ratio; S ac The short-circuit capacity at the point of interconnection (POI) of an AC system is expressed in MVA; P N The device capacity or maximum power of this node, in MW; U POI Z is the grid connection point voltage; N This is the Thevenin equivalent impedance magnitude of the AC system.

[0058] When the open-circuit voltage is 1.0 pu, the short-circuit ratio can be expressed as:

[0059]

[0060] That is, the formula for calculating the short-circuit ratio can be adjusted to:

[0061]

[0062] In the formula, P max S represents the maximum power of the fan. b Short-circuit capacity; This is the sum of the per-unit impedance values ​​of the system in question;

[0063] The system short-circuit ratio on the low-pressure side of the fan can be calculated.

[0064] Step S3: If the short-circuit ratio at the machine terminal is greater than that of the strong system, no action is taken; if the short-circuit ratio at the machine terminal is less than that of the strong system, a solution of configuring a synchronous condenser for the system is adopted.

[0065] Step S4: Calculate the required synchronous condenser capacity for the wind farm using the difference between the expected short-circuit ratio and the turbine terminal short-circuit ratio. Simultaneously compare the power output before and after configuring the synchronous condenser.

[0066] The required capacity of the synchronous condenser for the calculation system is determined by back-calculation of the short-circuit ratio difference ΔSCR. Since synchronous condensers are generally connected to the grid via transformers, the synchronous condenser and transformer must be integrated into the calculation during back-calculation.

[0067] The per-unit impedance of the camera is expressed as:

[0068]

[0069] In the formula, X″ d To adjust the camera impedance value; S b For short-circuit capacity; S SC Adjust the camera's capacity as required;

[0070] Using the short-circuit ratio formula, the synchronous condenser capacity S can be calculated. SC :

[0071]

[0072] In the formula, X″ d To adjust the camera impedance value; S b P is the short-circuit capacity; ΔSCR is the difference in short-circuit ratio that the system needs to compensate for; max S represents the maximum power of the fan. b Short-circuit capacity; The per-unit impedance value of the transformer on the camera side;

[0073] Step S5: Establish a wind farm grid access model. Based on the synchronous condenser parameters, simulate grid fault conditions at the PCC point to verify whether the terminal voltage of the wind turbine does not disconnect from the grid when the wind turbine is generating power at full power, thereby determining the improvement of the wind farm's power transmission capacity.

[0074] Example 1:

[0075] Wind farm grid connection system structure diagram, such as Figure 3 As shown; for this system, a baseline capacity S is selected. b The maximum power of the wind turbine is 100 Mvar. max It is 50.5MW, S SC Given an unknown synchronous condenser capacity; known system parameters: the short-circuit ratio on the low-voltage side of the wind turbine is 2.83, indicating the wind farm is under output limitation; after introducing an SVG short-circuit ratio of 0.12, the system short-circuit ratio is 2.95; using a strong system short-circuit ratio of 3 as the boundary, the difference ΔSCR = 0.5 is obtained; the preset synchronous condenser is connected to the low-voltage side of the main transformer through a 20MVA, 10.5kV three-phase winding transformer with an impedance per unit value of 0.525. The preset synchronous condenser impedance X″ is... d It is 0.12;

[0076] The per-unit impedance of the camera is then:

[0077]

[0078] Using the short-circuit ratio formula, the synchronous condenser capacity S can be calculated. SC :

[0079]

[0080] Based on the existing small-sized synchronous condenser products, select the closest capacity level.

[0081] Step 2: Build a system model based on SIMULINK, configure synchronous condensers for the weak grid system, and verify the power output of the wind farm before and after configuring the synchronous condensers;

[0082] Step 2 specifically includes the following steps:

[0083] Step 2.1: Connect the preset synchronous condenser to the wind farm, and consider the impact of the synchronous condenser connection on the wind farm's power transmission capacity, the system's short-circuit ratio, and the grid connection point voltage as a constraint to improve the wind farm's power transmission capacity.

[0084] Step 2.2: The objective function is to maximize the wind farm's power transmission capacity when a voltage drop fault occurs in the power grid.

[0085] Step 2.3: Based on the above constraints, conduct simulation tests on the objective function. Simulation tests include, but are not limited to, grid fault simulation, wind farm response analysis, and dynamic behavior analysis of SVG and synchronous condensers. The original system was a weak grid; when a fault occurred at the grid connection point, the wind farm in the system equipped only with SVG could not generate full capacity and the voltage exceeded limits. After introducing SC, the system short-circuit ratio was greatly improved, and the wind farm could achieve full capacity, such as... Figure 4 As shown.

[0086] In summary, the integration of synchronous condensers improves the system's short-circuit ratio and enhances voltage support capabilities, thus maintaining the wind farm's stable power transmission capacity during grid faults. Meanwhile, configuring SVG provides the necessary reactive power support to maintain grid voltage stability.

[0087] Device Example 1

[0088] According to an embodiment of the present invention, a device for configuring the capacity of a synchronous condenser in a wind farm is provided. Figure 5 This is a schematic diagram of the wind farm in-situ synchronous condenser capacity configuration device according to an embodiment of the present invention, as shown below. Figure 5 As shown, the power transmission capacity configuration device for a single grid-connected wind farm according to an embodiment of the present invention specifically includes:

[0089] Module 50 is used to acquire system parameters of the wind farm; specifically, it is used for:

[0090] Obtain the network topology and parameters of a wind farm, the installed capacity and number of wind farm turbines, reactive power compensation configuration information, as well as the main transformer parameters and equivalent parameters of the external power grid;

[0091] Configuration module 52 is used to calculate the short-circuit ratio at the wind turbine terminal based on the system parameters. When the short-circuit ratio at the wind turbine terminal is less than the short-circuit ratio of the main system, it calculates the required synchronous condenser capacity parameters for the wind farm based on the difference between the desired short-circuit ratio and the short-circuit ratio at the wind turbine terminal. Specifically, it is used for:

[0092] Based on the system parameters, the impedance values ​​of the power grid, high-voltage transmission lines, main transformer, SVG, box-type substation, and wind turbine-side transmission line section are calculated.

[0093] Based on the impedance value and the short-circuit ratio formula, the short-circuit ratio at the computer end and the short-circuit ratio of the reactive power equipment in the original system configuration;

[0094] When the short-circuit ratio at the turbine terminal is less than the short-circuit ratio of the strong system, the difference between the expected short-circuit ratio and the short-circuit ratio at the turbine terminal plus the short-circuit ratio of the original system reactive equipment is obtained.

[0095] Calculate the impedance values ​​of the components on the parallel-connected side of the synchronous condenser, and using the short-circuit ratio formula, calculate the required synchronous condenser capacity from the short-circuit ratio difference. Specifically, the components considered on the parallel-connected side of the synchronous condenser include: a step-up transformer and the synchronous condenser. Specifically:

[0096] Calculate the per-unit impedance value of the synchronous condenser according to Formula 1:

[0097]

[0098] Where, X″ d To adjust the camera impedance value; S b For short-circuit capacity; S SC Adjust the camera's capacity as required;

[0099] Based on Formula 2 and the short-circuit ratio formula, the synchronous condenser capacity S can be calculated. SC :

[0100]

[0101] Where, X″ d To adjust the camera impedance value; S b P is the short-circuit capacity; ΔSCR is the difference in short-circuit ratio that the system needs to compensate for; max S represents the maximum power of the fan. b Short-circuit capacity; This refers to the per-unit impedance value of the transformer on the camera side.

[0102] The device further includes:

[0103] The verification module is used to establish a wind farm grid access model. Based on the synchronous condenser parameters, it simulates grid fault conditions at the PCC point to verify whether the turbine terminal voltage does not disconnect from the grid when the wind turbine is generating power at full power, thereby determining the improvement of the wind farm's power transmission capacity.

[0104] The embodiments of the invention are device embodiments corresponding to the method embodiments described above. The specific operation of each module can be understood with reference to the description of the method embodiments, and will not be repeated here.

[0105] Device Example 2

[0106] This invention provides an electronic device, such as... Figure 6 As shown, it includes: a memory 60, a processor 62, and a computer program stored in the memory 60 and executable on the processor 62, wherein the computer program, when executed by the processor 62, performs the steps as described in the method embodiment.

[0107] Device Example 3

[0108] This invention provides a computer-readable storage medium storing an information transmission implementation program, which, when executed by a processor 62, performs the steps described in the method embodiment.

[0109] The computer-readable storage media described in this embodiment include, but are not limited to, ROM, RAM, disk, or optical disk.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for configuring the capacity of synchronous condensers within a wind farm, characterized in that, include: Obtain system parameters of the wind farm; Based on the system parameters, the short-circuit ratio at the wind turbine terminal is calculated. When the short-circuit ratio at the wind turbine terminal is less than the short-circuit ratio of the main system, the required synchronous condenser capacity parameters for the wind farm are calculated based on the difference between the desired short-circuit ratio and the short-circuit ratio at the wind turbine terminal. Specifically, this includes: Based on the system parameters, the impedance values ​​of the power grid, high-voltage transmission lines, main transformer, SVG, box-type substation, and wind turbine-side transmission line section are calculated. Based on the impedance value and the short-circuit ratio formula, the short-circuit ratio at the computer end and the short-circuit ratio of the reactive power equipment in the original system configuration; When the short-circuit ratio at the turbine terminal is less than the short-circuit ratio of the strong system, the difference between the expected short-circuit ratio and the short-circuit ratio at the turbine terminal plus the short-circuit ratio of the original system reactive equipment is obtained. Calculate the impedance value of the parallel-connected components of the synchronous condenser, and using the short-circuit ratio formula, calculate the required synchronous condenser capacity from the short-circuit ratio difference. Specifically, the parallel-connected components of the synchronous condenser include: a step-up transformer and a synchronous condenser; specifically including: Calculate the per-unit impedance value of the synchronous condenser according to Formula 1: Formula 1: in, To adjust the camera impedance value; Short-circuit capacity; Adjust the camera's capacity as required; Based on Formula 2 and the short-circuit ratio formula, the capacity of the synchronous condenser can be calculated. : Formula 2: in, To adjust the camera impedance value; Short-circuit capacity; This is the difference in short-circuit ratio that the system needs to compensate for; This is the maximum power of the fan; Short-circuit capacity; The per-unit impedance value of the transformer on the camera side; A wind farm grid access model is established. Based on the synchronous condenser parameters, grid fault conditions are simulated at the PCC point to verify whether the turbine terminal voltage does not disconnect from the grid when the wind turbine is generating at full power, thereby determining the improvement of the wind farm's power transmission capacity.

2. The method according to claim 1, characterized in that, The specific system parameters for obtaining wind farm parameters include: Obtain the network topology and parameters of a wind farm, the installed capacity and number of wind farm turbines, reactive power compensation configuration information, as well as the main transformer parameters and equivalent parameters of the external power grid.

3. A device for configuring the capacity of a synchronous condenser in a wind farm, characterized in that, include: The acquisition module is used to acquire system parameters of the wind farm; The configuration module is used to calculate the short-circuit ratio at the wind turbine terminal based on the system parameters. When the short-circuit ratio at the wind turbine terminal is less than the short-circuit ratio of the main system, it calculates the required synchronous condenser capacity parameters for the wind farm based on the difference between the desired short-circuit ratio and the short-circuit ratio at the wind turbine terminal. Specifically, the configuration module is used for: Based on the system parameters, the impedance values ​​of the power grid, high-voltage transmission lines, main transformer, SVG, box-type substation, and wind turbine-side transmission line section are calculated. Based on the impedance value and the short-circuit ratio formula, the short-circuit ratio at the computer end and the short-circuit ratio of the reactive power equipment in the original system configuration; When the short-circuit ratio at the turbine terminal is less than the short-circuit ratio of the strong system, the difference between the expected short-circuit ratio and the short-circuit ratio at the turbine terminal plus the short-circuit ratio of the original system reactive equipment is obtained. Calculate the impedance value of the parallel-connected components of the synchronous condenser, and using the short-circuit ratio formula, calculate the required synchronous condenser capacity from the short-circuit ratio difference. Specifically, the parallel-connected components of the synchronous condenser include: a step-up transformer and a synchronous condenser; specifically used for: Calculate the per-unit impedance value of the synchronous condenser according to Formula 1: Formula 1: in, To adjust the camera impedance value; Short-circuit capacity; Adjust the camera's capacity as required; Based on Formula 2 and the short-circuit ratio formula, the capacity of the synchronous condenser can be calculated. : Formula 2: in, To adjust the camera impedance value; Short-circuit capacity; This is the difference in short-circuit ratio that the system needs to compensate for; This is the maximum power of the fan; Short-circuit capacity; The per-unit impedance value of the transformer on the camera side; The verification module is used to establish a wind farm grid access model. Based on the synchronous condenser parameters, it simulates grid fault conditions at the PCC point to verify whether the turbine terminal voltage does not disconnect from the grid when the wind turbine is generating power at full power, thereby determining the improvement of the wind farm's power transmission capacity.

4. The apparatus according to claim 3, characterized in that, The acquisition module is specifically used for: Obtain the network topology and parameters of a wind farm, the installed capacity and number of wind farm turbines, reactive power compensation configuration information, as well as the main transformer parameters and equivalent parameters of the external power grid.

5. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the wind farm synchronous condenser capacity configuration method as described in any one of claims 1 to 2.

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