Wind power plant grid-connected control method and device and electronic equipment

Abstract

The invention provides a wind power plant grid-connected control method and device and electronic equipment, and the method comprises the steps: monitoring the maximum active power which can be captured by each operating wind turbine generator set in a wind power plant, and enabling the grid-connected operation mode of each operating wind turbine generator set to be a network-following operation mode or a network-constructing operation mode; according to the magnitude of the maximum active power capable of being captured by each wind turbine generator set running in the following grid type, sorting the wind turbine generator sets in the following grid type to obtain a sorting result; acquiring the power grid strength of the current wind power plant; when the power grid strength is smaller than the target power grid strength, according to the number of the wind turbine generators in each grid-connected operation mode, the target power grid strength and the sorting result, the number of the wind turbine generators in grid-following operation is adjusted, so that the power grid strength of the wind power plant reaches the target power grid strength or above; wherein the target power grid strength is the power grid strength corresponding to the lowest short-circuit ratio allowed by the grid-connected point of the wind turbine generator. According to the method provided by the invention, the wind turbine generator set can be prevented from being pulled down due to the fact that the wind turbine generator set is set to be in network construction type operation and the frequency of the power grid is changed when the wind turbine generator set runs at low power, and the problems of component breakage and shortened service life caused by pulling down are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wind farm grid-connected control, and in particular to a wind farm grid-connected control method, device and electronic equipment. Background Art

[0002] Renewable energy generation is connected to the grid through converters. Traditional renewable energy generators work in the grid-following operation mode, which is essentially a controlled current source. Large-scale access will reduce the resilience of the grid and bring great challenges to the frequency and voltage stability of the system. With the emergence of relevant grid support needs and the improvement of regulations, the advantages of voltage source wind power converters in grid-controlled wind power will gradually emerge, which has great potential application value in improving the grid friendliness of wind farms and ensuring the safe operation of power systems.

[0003] Using grid-forming control for wind turbines has advantages over using grid-following control in terms of grid frequency support. This is because grid-forming control has a frequency support characteristic that responds spontaneously to changes in grid frequency. When the grid frequency changes, there is no need to detect the grid frequency, and the wind turbine will automatically respond with power.

[0004] However, when the wind turbine is operating at low power, the spontaneous response frequency support characteristics will increase the risk of the wind turbine being pulled down when encountering a grid frequency drop event, increase fatigue wear on unit components, and prolong the time it takes for the wind turbine to be restarted and connected to the grid after clearing the fault; when the grid frequency rises, it is easy to cause the wind turbine output to be blocked and the energy-consuming devices to operate additionally, which can easily shorten the service life of the wind turbine's energy-consuming devices. Summary of the invention

[0005] The present invention provides a wind farm grid-connected control method, device and electronic equipment, which can avoid the wind turbine being pulled down by the change of grid frequency when the wind turbine is set to grid-connected operation when the wind turbine is running at low power, and reduce the problems of component damage and reduced service life caused by this.

[0006] According to a first aspect of an embodiment of the present invention, a wind farm grid connection control method is provided, the method comprising:

[0007] Monitor the maximum active power that can be captured by each wind turbine in operation in the wind farm, wherein the grid-connected operation mode of each wind turbine in operation is grid-following operation or grid-building operation;

[0008] According to the maximum active power that can be captured by each wind turbine in grid-following operation, the wind turbines in grid-following operation are sorted to obtain a sorting result;

[0009] Get the current grid strength of the wind farm;

[0010] When the grid strength is less than the target grid strength, the number of wind turbines in grid-following operation is adjusted according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking results, so that the grid strength of the wind farm reaches above the target grid strength;

[0011] The target grid strength is the grid strength corresponding to the minimum short-circuit ratio allowed at the grid connection point of the wind turbine.

[0012] In a possible implementation, after monitoring the maximum active power that can be captured by each wind turbine operating in the wind farm, the method further includes:

[0013] According to the maximum active power that each wind turbine can capture, the grid-connected operation mode of each wind turbine is set, and the number of wind turbines in each grid-connected operation mode is obtained.

[0014] In a possible implementation, the grid-connected operation mode of each wind turbine is set according to the maximum active power that each wind turbine can capture, including:

[0015] Compare the maximum active power that can be captured by each wind turbine with the grid-building operation power threshold and the grid-following operation power threshold;

[0016] The wind turbines whose maximum active power that can be captured is greater than the grid-building operation power threshold are set to grid-building operation;

[0017] Set the wind turbine generator set whose maximum active power that can be captured is less than the grid-following operation power threshold to grid-following operation;

[0018] Among them, the grid-following operation power threshold is equal to the difference between the grid-building operation power threshold and the power hysteresis threshold.

[0019] In a possible implementation, the number of wind turbines in grid-connected operation is adjusted according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result, including:

[0020] According to the target grid strength, determining the first proportion of the number of wind turbines whose grid-connected operation mode is grid-configuration operation among the operating wind turbines;

[0021] According to the number of wind turbines in each grid-connected operation mode and the first proportion, the number N of wind turbines in grid-connected operation mode that need to be shut down is determined;

[0022] According to the sorting results, the N wind turbines operating in grid-following mode with the smallest maximum active power that can be captured are shut down.

[0023] In a possible implementation, after determining the number N of wind turbines in grid-connected operation that need to be shut down according to the number of wind turbines in each grid-connected operation mode and the first proportion, the method further includes:

[0024] Determine the impedance characteristic curve of the wind farm according to the impedance characteristic curves of each wind turbine operating in the wind farm;

[0025] When the phase of the frequency band concerned by the impedance characteristic curve of the wind farm is outside the target phase range, the second proportion of the number of wind turbines in grid-type operation in the operating wind turbines is determined according to the impedance of the wind farm, the impedance of the wind turbines in grid-type operation, and the impedance of the wind turbines in grid-following operation;

[0026] According to the number and second proportion of wind turbines in each grid-connected operation mode, the number M of wind turbines in grid-connected operation mode that need to be shut down is determined;

[0027] Determine the larger value of N and M, max(M,N), as the number of wind turbines in grid-following operation that need to be shut down;

[0028] According to the sorting results, the wind turbines operating in the grid-following mode with the smallest max(M,N) maximum active power that can be captured will be shut down.

[0029] In a possible implementation, obtaining the grid strength of a wind farm includes:

[0030] Control the running wind turbines to inject disturbing harmonic currents of non-characteristic sub-frequency into the access point;

[0031] Collect grid voltage and grid current at the grid connection point of the operating wind turbine;

[0032] Perform Fast Fourier Transform (FFT) analysis on the grid voltage and grid-connected current respectively, and obtain the voltage FFT analysis result and the current FFT analysis result respectively;

[0033] The harmonic voltage component and the harmonic current component of the disturbance frequency are extracted from the voltage FFT analysis results and the current FFT analysis results respectively.

[0034] Calculate the equivalent grid impedance of each wind turbine access point in operation based on the harmonic voltage and current components of the disturbance frequency;

[0035] Determine the maximum value of the equivalent grid impedance of each wind turbine access point as the grid equivalent impedance corresponding to the wind farm grid strength;

[0036] The reciprocal of the grid equivalent impedance corresponding to the grid strength is taken and the reciprocal is used as the grid strength of the wind farm.

[0037] According to a second aspect of an embodiment of the present invention, a wind farm grid connection control device is provided, the device comprising:

[0038] A monitoring module is used to monitor the maximum active power that can be captured by each wind turbine in operation in the wind farm; wherein the grid-connected operation mode of each wind turbine in operation is a grid-following operation or a grid-building operation;

[0039] A sorting module is used to sort the wind turbines of the grid-following type according to the maximum active power that can be captured by each wind turbine of the grid-following type operation mode, and obtain a sorting result;

[0040] An acquisition module is used to obtain the current power grid strength of the wind farm;

[0041] An adjustment module is used to adjust the number of wind turbines in grid-following operation according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result when the grid strength is less than the target grid strength, so that the grid strength of the wind farm reaches above the target grid strength;

[0042] The target grid strength is the grid strength corresponding to the minimum short-circuit ratio allowed at the grid connection point of the wind turbine.

[0043] In a possible implementation, the device further includes a setting module;

[0044] The setting module is used to set the grid-connected operation mode of each wind turbine according to the maximum active power that each wind turbine can capture, and obtain the number of wind turbines in each grid-connected operation mode.

[0045] In a possible implementation, a module is provided, specifically for:

[0046] Compare the maximum active power that can be captured by each wind turbine with the grid-building operation power threshold and the grid-following operation power threshold;

[0047] The wind turbines whose maximum active power that can be captured is greater than the grid-building operation power threshold are set to grid-building operation;

[0048] Set the wind turbine generator set whose maximum active power that can be captured is less than the grid-following operation power threshold to grid-following operation;

[0049] Among them, the grid-following operation power threshold is equal to the difference between the grid-building operation power threshold and the power hysteresis threshold.

[0050] According to a third aspect of an embodiment of the present invention, an electronic device, a processor and a memory storing computer program instructions are provided; when the processor executes the computer program instructions, the wind farm grid-connected control method in the first aspect of the present invention or any possible implementation method of the first aspect is implemented.

[0051] The embodiment of the present invention provides a wind farm grid connection control method, device and electronic equipment, which monitor the maximum active power that can be captured by each wind turbine operating in the wind farm. When the grid strength of the wind farm is less than the target grid strength, the number of wind turbines operating in the grid-following mode is adjusted based on the target grid strength, so that the grid strength of the wind farm reaches or exceeds the target grid strength. By controlling the grid connection and shutdown of wind turbines, energy constraints are performed, and the short-circuit ratio requirements of the grid are adapted, the problem of wind turbines being pulled down by grid frequency changes when the wind turbines are set to grid-forming mode operation when the wind turbines are running at low power is avoided, and the problems of component damage and reduced service life caused by this are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0053] Figure 1 A schematic flow chart of a wind farm grid connection control method provided by an embodiment of the present invention;

[0054] Figure 2 A schematic diagram of the structure of a wind farm grid-connected control device provided by an embodiment of the present invention;

[0055] Figure 3 A schematic diagram of the hardware structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Embodiment 1

[0058] The embodiment of the present application provides a wind farm grid connection control method, the execution subject is a voltage source wind power converter, such as Figure 1 As shown, the control method may include the following steps:

[0059] S110, monitoring the maximum active power that can be captured by each wind turbine generator set operating in the wind farm.

[0060] As factors such as wind speed and wind direction change, the maximum active power that can be captured by the wind turbines fluctuates accordingly. The maximum active power that can be captured by each wind turbine operating in the wind farm is monitored in real time.

[0061] S120, sorting the wind turbines of the grid-following type according to the maximum active power that can be captured by each wind turbine of the grid-following type operation mode, and obtaining a sorting result.

[0062] According to the maximum active power that can be captured by each wind turbine generator set whose grid-connected operation mode is grid-following operation, the wind turbine generator sets operating in the grid-following operation mode are sorted from large to small according to the maximum active power that can be captured, and a sorting result is obtained.

[0063] S130, obtaining the current power grid strength of the wind farm.

[0064] The wind farm is tested for the current grid strength by injecting disturbed harmonic currents at the access points of the wind turbines.

[0065] S140, when the grid strength is less than the target grid strength, the number of wind turbines in grid-connected operation is adjusted according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result, so that the grid strength of the wind farm reaches above the target grid strength.

[0066] The target grid strength is the grid strength corresponding to the minimum short-circuit ratio allowed at the grid connection point of the wind turbine. The minimum short-circuit ratio meets the requirements of the short-circuit ratio of multiple stations for the safe and stable operation of the power system for the new energy grid connection point.

[0067] If the grid strength is less than the target grid strength, it means that the short-circuit ratio of the current wind farm does not meet the requirements of the short-circuit ratio of multiple stations at renewable energy grid-connected points for safe and stable operation of the power system. At least according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking results, the number of wind turbines in grid-following operation should be adjusted to make the grid strength of the wind farm reach above the target grid strength, thereby meeting the requirements of the short-circuit ratio of multiple stations at renewable energy grid-connected points for safe and stable operation of the power system.

[0068] After the grid frequency returns to the normal range, the shut-down wind turbines can be restarted.

[0069] The embodiment of the present invention provides a wind farm grid connection control method, which monitors the maximum active power that can be captured by each wind turbine operating in the wind farm, sets the grid connection operation mode of each wind turbine, and when the grid strength of the wind farm is less than the target grid strength, adjusts the number of wind turbines in grid-following operation based on the target grid strength, so that the grid strength of the wind farm reaches above the target grid strength. By controlling the grid connection and shutdown of wind turbines, performing energy constraints, and adapting to the short-circuit ratio requirements of the grid, it is possible to avoid the wind turbines being pulled down by the grid frequency changes when the wind turbines are set to grid-forming operation when they are running at low power, and reduce the problems of component damage and reduced service life caused by this.

[0070] Embodiment 2

[0071] In some embodiments, after S110: monitoring the maximum active power that can be captured by each wind turbine operating in the wind farm, the method may further include the following steps:

[0072] S150, setting a grid-connected operation mode for each wind turbine generator set according to the maximum active power that each wind turbine generator set can capture, and obtaining the number of wind turbine generator sets in each grid-connected operation mode.

[0073] Compare the maximum active power that each wind turbine can capture with the grid-building operation power threshold and the grid-following operation power threshold; set the wind turbine whose maximum active power can be captured is greater than the grid-building operation power threshold to grid-building operation; set the wind turbine whose maximum active power can be captured is less than the grid-following operation power threshold to grid-following operation. After the setting is completed, count the number of wind turbines in grid-building operation and the number of wind turbines in grid-following operation.

[0074] Among them, the grid-following operation power threshold is equal to the grid-building operation power threshold P WT_Lmt and power hysteresis threshold ΔP WT_GFMLmt The difference, ΔP WT_GFMLmt ≥0.

[0075] Since the maximum active power that the wind turbine can capture is in a fluctuating state, the maximum active power that can be captured is [P WT_Lmt -ΔP WT_GFMLmt , P WT_Lmt ] range, the wind turbines can be set to either grid-following operation or grid-building operation, and the maximum active power that the wind turbine can capture increases to greater than P WT_Lmt When the maximum active power that the wind turbine can capture is reduced to less than P WT_Lmt -ΔP WT_GFMLmt When the system is running, it is set to follow the network.

[0076] After the grid frequency returns to the normal range, restart the shut-down wind turbine and monitor the maximum active power that the wind turbine can capture according to the above method to set the operation mode of the wind turbine.

[0077] The method provided by the embodiment of the present invention dynamically sets the operation mode of the wind turbine generator set to ensure the stable operation of the wind farm.

[0078] Embodiment 3

[0079] In some embodiments, S130: obtaining the grid strength of the wind farm may include the following steps:

[0080] S131, controlling the running wind turbine to inject a disturbance harmonic current of a non-characteristic subfrequency into the access point.

[0081] Control some or all of the wind turbines in operation and inject disturbing harmonic currents of non-characteristic sub-frequency into access points of the wind turbines.

[0082] S132, collecting grid voltage and grid current at the grid connection point of the running wind turbine generator set.

[0083] The grid voltage and grid current are collected at the grid connection point of the wind turbine generator set that injects the disturbing harmonic current.

[0084] S143, performing FFT analysis on the grid voltage and the grid-connected current, respectively, to obtain voltage FFT analysis results and current FFT analysis results, respectively.

[0085] S134, extracting the harmonic voltage component and the harmonic current component of the disturbance frequency from the voltage FFT analysis result and the current FFT analysis result respectively.

[0086] S135, calculating the equivalent grid impedance of each wind turbine access point in operation according to the harmonic voltage component and current component of the disturbance frequency.

[0087] It is expressed by the following formula:

[0088]

[0089] Among them, Z gj represents the equivalent grid impedance at the access point of the j-th wind turbine; represents the harmonic voltage component of the grid-connected point of the j-th wind turbine; Represents the harmonic current component of the grid-connected point of the j-th wind turbine.

[0090] S136, determining the maximum value of the equivalent grid impedances of the access points of the wind turbine generator sets as the grid equivalent impedance corresponding to the grid strength of the wind farm.

[0091] S137, taking the inverse of the grid equivalent impedance corresponding to the grid strength, and using the inverse as the grid strength of the wind farm.

[0092] The method provided in the embodiment of the present invention determines the current grid strength of the wind farm as a basis for adjusting the operation of the wind turbines.

[0093] Embodiment 4

[0094] In some embodiments, in S140: adjusting the number of wind turbines in grid-following operation according to at least the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result may include the following steps:

[0095] S141, according to the target grid strength, determining a first proportion of the number of wind turbines whose grid-connected operation mode is grid-configuration operation among the operating wind turbines.

[0096] The first proportion is calculated using the following formula:

[0097]

[0098] Among them, λ GFM_W1 Indicates the first proportion; SCR0 indicates the initial short-circuit ratio of the wind farm. The initial short-circuit ratio is the short-circuit ratio when all wind turbines in the wind farm are operated in the grid-following mode. It is obtained by dividing the short-circuit capacity of the wind farm access point by the capacity of the wind turbines in operation; SCR minLmt Indicates the target power grid strength; K w Indicates the ratio of short-circuit current to rated current, K w ≥1.

[0099] S142: Determine the number N of wind turbines in grid-connected operation that need to be shut down according to the number of wind turbines in each grid-connected operation mode and the first proportion.

[0100] According to the number of wind turbines in grid-building operation, the number of wind turbines in grid-following operation and the first proportion, the number of wind turbines in grid-following operation when the first proportion is met is determined, and the difference between the number of wind turbines in grid-following operation when the first proportion is met and the current number of wind turbines in grid-following operation is calculated to obtain the number N of wind turbines in grid-following operation that need to be shut down.

[0101] S143, according to the sorting result, shut down the N wind turbines in grid-following operation that have the smallest maximum active power that can be captured.

[0102] After the method provided in the embodiment of the present invention adjusts the number of wind turbines in grid-following operation, the wind farm meets the requirements of the multi-station short-circuit ratio of the new energy grid connection point for the safe and stable operation of the power system, thereby ensuring the safe and stable operation of the power system.

[0103] Embodiment 5

[0104] In some embodiments, it is also considered whether the proportion of wind turbines in the current grid-type operation can meet the requirements of stable operation of the wind farm with small disturbances. After S142 in the method described in the fourth embodiment, the following steps may also be included:

[0105] S144, determining an impedance characteristic curve of the wind farm according to the impedance characteristic curves of each wind turbine operating in the wind farm.

[0106] The impedance characteristic curve of the wind farm is calculated based on the impedance characteristic curve of the wind turbines operating in a grid-forming mode and the impedance characteristic curve of the wind turbines operating in a grid-following mode.

[0107] The impedance of the wind farm, the impedance of the wind turbines in grid-forming operation, and the impedance of the wind turbines in grid-following operation can be obtained respectively from the impedance characteristic curve of the wind farm, the impedance characteristic curve of the wind turbines in grid-forming operation, and the impedance of the wind turbines in grid-following operation.

[0108] S145, when the phase of the frequency band concerned by the impedance characteristic curve of the wind farm is outside the target phase range, determine the second proportion of the number of wind turbines in grid-type operation in the operating wind turbines based on the impedance of the wind farm, the impedance of the wind turbines in grid-type operation, and the impedance of the wind turbines in grid-following operation.

[0109] The target phase range is -90°~90°. If the phase of the frequency band concerned by the impedance characteristic curve of the wind farm is within the range of -90°~90°, it is considered that the current proportion of grid-connected wind turbines can meet the requirements of stable operation with small interference of the wind farm, and the number of grid-connected wind turbines that need to be shut down is 0; if the phase of the frequency band concerned by the impedance characteristic curve of the wind farm is not within the range of -90°~90°, the phase of the frequency band concerned by the impedance characteristic curve of the wind farm does not meet the requirements of stable operation with small interference of the wind farm.

[0110] According to the impedance of the wind farm, the impedance of the wind turbines in grid-type operation and the impedance of the wind turbines in grid-following operation, the second proportion of the number of wind turbines in grid-type operation in the operating wind turbines is determined, which is expressed by the following formula:

[0111] λ GFM_W2 =(Z GFL_W Z GFM_W / Z WT -Z GFM_W )

[0112] Among them, λ GFM_W2 Indicates the second proportion; Z GFL_W Indicates the impedance of the wind turbine in grid-following operation; Z GFM_W Represents the impedance of wind turbines in grid-type operation; ZWT Represents the impedance of the wind farm.

[0113] S146, determining the number M of wind turbines in grid-connected operation that need to be shut down according to the number of wind turbines in each grid-connected operation mode and the second proportion.

[0114] According to the number of wind turbines in grid-building operation, the number of wind turbines in grid-following operation and the second proportion, the number of wind turbines in grid-following operation when the second proportion is met is determined, and the difference between the number of wind turbines in grid-following operation when the second proportion is met and the current number of wind turbines in grid-following operation is calculated to obtain the number M of wind turbines in grid-following operation that need to be shut down.

[0115] S147, determining the larger value max(M, N) of N and M as the number of wind turbines in grid-following operation that need to be shut down.

[0116] S148, according to the sorting result, the wind turbines in grid-following operation with the maximum (M, N) units that can capture the smallest maximum active power are shut down.

[0117] After the method provided in the embodiment of the present invention adjusts the number of wind turbines in grid-following operation, the wind farm simultaneously meets the requirements of the multi-station short-circuit ratio of the new energy grid-connected points for safe and stable operation of the power system and the requirements of the wind farm for stable operation with small disturbances, thereby ensuring the safe and stable operation of the power system.

[0118] Embodiment 6

[0119] Accordingly, the embodiment of the present invention also provides a wind farm grid connection control device, such as Figure 2 As shown, the wind farm grid-connected control device 200 may include a monitoring module 210, a sorting module 220, an acquisition module 230 and an adjustment module 240, wherein:

[0120] The monitoring module 210 is used to monitor the maximum active power that can be captured by each wind turbine in operation in the wind farm; wherein the grid-connected operation mode of each wind turbine in operation is a grid-following operation or a grid-building operation;

[0121] A sorting module 220 is used to sort the wind turbines of the grid-following type according to the maximum active power that can be captured by each wind turbine of the grid-following type operation mode, and obtain a sorting result;

[0122] An acquisition module 230 is used to acquire the current power grid strength of the wind farm;

[0123] The adjustment module 240 is used to adjust the number of wind turbines in grid-following operation mode when the grid strength is less than the target grid strength, at least according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result, so that the grid strength of the wind farm reaches above the target grid strength;

[0124] The target grid strength is the grid strength corresponding to the minimum short-circuit ratio allowed at the grid connection point of the wind turbine.

[0125] After the grid frequency returns to the normal range, the shut-down wind turbines can be restarted.

[0126] The embodiment of the present invention provides a wind farm grid connection control device, which monitors the maximum active power that can be captured by each wind turbine operating in the wind farm. When the grid strength of the wind farm is less than the target grid strength, the number of wind turbines operating in the grid-following mode is adjusted based on the target grid strength, so that the grid strength of the wind farm reaches or exceeds the target grid strength. By controlling the grid connection and shutdown of wind turbines, energy constraints are performed, and the short-circuit ratio requirements of the grid are adapted, it is possible to avoid the wind turbines being pulled down by the grid frequency changes when the wind turbines are set to grid-forming mode operation when the wind turbines are running at low power, and reduce the problems of component damage and reduced service life caused by this.

[0127] Embodiment 7

[0128] In some embodiments, the wind farm grid-connected control device 200 further includes a setting module 250;

[0129] The setting module 250 is used to set the grid-connected operation mode of each wind turbine generator set according to the maximum active power that each wind turbine generator set can capture, and obtain the number of wind turbine generator sets in each grid-connected operation mode.

[0130] Specifically, the module 250 is configured to:

[0131] Compare the maximum active power that each wind turbine can capture with the grid-building operation power threshold and the grid-following operation power threshold; set the wind turbine whose maximum active power can be captured is greater than the grid-building operation power threshold to grid-building operation; set the wind turbine whose maximum active power can be captured is less than the grid-following operation power threshold to grid-following operation. After the setting is completed, count the number of wind turbines in grid-building operation and the number of wind turbines in grid-following operation.

[0132] Among them, the grid-following operation power threshold is equal to the grid-building operation power threshold P WT_Lmt and power hysteresis threshold ΔP WT_GFMLmt The difference, ΔP WT_GFMLmt ≥0.

[0133] Since the maximum active power that the wind turbine can capture is in a fluctuating state, the maximum active power that can be captured is [P WT_Lmt -ΔP WT_GFMLmt , P WT_Lmt ] range, the wind turbines can be set to either grid-following operation or grid-building operation, and the maximum active power that the wind turbine can capture increases to greater than P WT_Lmt When the maximum active power that the wind turbine can capture is reduced to less than P WT_Lmt -ΔP WT_GFMLmt When the system is running, it is set to follow the network.

[0134] After the grid frequency returns to the normal range, restart the shut-down wind turbine and monitor the maximum active power that the wind turbine can capture according to the above method to set the operation mode of the wind turbine.

[0135] The method provided by the embodiment of the present invention dynamically sets the operation mode of the wind turbine generator set to ensure the stable operation of the wind farm.

[0136] Embodiment 8

[0137] In some embodiments, the acquisition module 230 is specifically configured to:

[0138] Control the running wind turbines to inject disturbing harmonic currents of non-characteristic sub-frequency into the access point;

[0139] Collect grid voltage and grid current at the grid connection point of the operating wind turbine;

[0140] Perform FFT analysis on the grid voltage and grid-connected current respectively, and obtain the voltage FFT analysis result and the current FFT analysis result respectively;

[0141] Extract the harmonic voltage component and the harmonic current component of the disturbance frequency from the voltage FFT analysis results and the current FFT analysis results respectively;

[0142] Calculate the equivalent grid impedance of each wind turbine access point in operation based on the harmonic voltage and current components of the disturbance frequency;

[0143] Determine the maximum value of the equivalent grid impedance of each wind turbine access point as the grid equivalent impedance corresponding to the wind farm grid strength;

[0144] The reciprocal of the grid equivalent impedance corresponding to the grid strength is taken and the reciprocal is used as the grid strength of the wind farm.

[0145] The method provided in the embodiment of the present invention determines the current grid strength of the wind farm as a basis for adjusting the operation of the wind turbines.

[0146] Embodiment 9

[0147] In some embodiments, the adjustment module 240 is specifically configured to:

[0148] According to the target grid strength, determining the first proportion of the number of wind turbines whose grid-connected operation mode is grid-configuration operation among the operating wind turbines;

[0149] According to the number of wind turbines in each grid-connected operation mode and the first proportion, the number N of wind turbines in grid-connected operation mode that need to be shut down is determined;

[0150] According to the sorting results, the N wind turbines operating in grid-following mode with the smallest maximum active power that can be captured are shut down.

[0151] After the device provided by the embodiment of the present invention adjusts the number of wind turbines in grid-following operation, the wind farm meets the requirements of the multi-station short-circuit ratio of the new energy grid-connected points for the safe and stable operation of the power system, thereby ensuring the safe and stable operation of the power system.

[0152] Embodiment 10

[0153] In some embodiments, the adjustment module 240 may also be specifically used to:

[0154] Determine the impedance characteristic curve of the wind farm according to the impedance characteristic curves of each wind turbine operating in the wind farm;

[0155] When the phase of the frequency band concerned by the impedance characteristic curve of the wind farm is outside the target phase range, the second proportion of the number of wind turbines in grid-type operation in the operating wind turbines is determined according to the impedance of the wind farm, the impedance of the wind turbines in grid-type operation, and the impedance of the wind turbines in grid-following operation;

[0156] According to the number and second proportion of wind turbines in each grid-connected operation mode, the number M of wind turbines in grid-connected operation mode that need to be shut down is determined;

[0157] Determine the larger value max(M, N) of N and M as the number of wind turbines in grid-following operation that need to be shut down;

[0158] According to the sorting result, the wind turbines operating in the grid-following mode with the smallest max(M, N) maximum active power that can be captured are shut down.

[0159] After the device provided by the embodiment of the present invention adjusts the number of wind turbines in grid-following operation, the wind farm can simultaneously meet the requirements of the multi-station short-circuit ratio of the new energy grid-connected points for safe and stable operation of the power system and the requirements of the wind farm for stable operation with small disturbances, thereby ensuring the safe and stable operation of the power system.

[0160] The wind farm grid-connected control device provided in this embodiment belongs to the same inventive concept as the wind farm grid-connected control method provided in the above embodiments of the present invention, can execute the wind farm grid-connected control method provided in any of the above embodiments of the present invention, and has the corresponding functional modules and beneficial effects of executing the wind farm grid-connected control method. For technical details not fully described in this embodiment, please refer to the specific processing content of the wind farm grid-connected control method provided in the above embodiments of the present invention, and will not be repeated here.

[0161] Embodiment 11

[0162] Another embodiment of the present invention further provides an electronic device, see Figure 3 As shown, the device includes:

[0163] Memory 300 and processor 310;

[0164] The memory 300 is connected to the processor 310 and is used to store programs;

[0165] The processor 310 is used to implement the wind farm grid-connection control method disclosed in any of the above embodiments by running the program stored in the memory 300 .

[0166] Specifically, the electronic device may further include: a bus, a communication interface 320 , an input device 330 and an output device 340 .

[0167] The processor 310, the memory 300, the communication interface 320, the input device 330 and the output device 340 are connected to each other via a bus.

[0168] A bus may include a pathway that transfers information between components of a computer system.

[0169] The processor 310 may be a general-purpose processor, such as a general-purpose central processing unit (CPU), a microprocessor, etc., or an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the scheme of the present invention. It may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0170] The processor 310 may include a main processor, and may also include a baseband chip, a modem, and the like.

[0171] The memory 300 stores a program for executing the technical solution of the present invention, and may also store an operating system and other key services. Specifically, the program may include a program code, and the program code includes a computer operation instruction. More specifically, the memory 300 may include a read-only memory (ROM), other types of static storage devices that can store static information and instructions, a random access memory (RAM), other types of dynamic storage devices that can store information and instructions, a disk storage, a flash, and the like.

[0172] The input device 330 may include a device for receiving data and information input by a user, such as a keyboard, a mouse, a camera, a scanner, a light pen, a voice input device, a touch screen, etc.

[0173] Output device 340 may include devices that allow information to be output to a user, such as a display screen, printer, speaker, etc.

[0174] The communication interface 320 may include any transceiver or the like to communicate with other devices or communication networks, such as Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), etc.

[0175] The processor 310 executes the program stored in the memory 300 and calls other devices, and can be used to implement each step of any wind farm grid-connected control method provided by the above embodiments of the present invention.

[0176] For the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0177] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0178] The steps in the methods of the embodiments of the present invention may be adjusted in order, combined, or deleted according to actual needs, and the technical features recorded in the embodiments may be replaced or combined.

[0179] The modules and sub-modules in the devices and terminals of the various embodiments of the present invention may be combined, divided, or deleted according to actual needs.

[0180] In the several embodiments provided by the present invention, it should be understood that the disclosed terminals, devices and methods can be implemented in other ways. For example, the terminal embodiments described above are only schematic, for example, the division of modules or submodules is only a logical function division, and there may be other division methods in actual implementation, such as multiple submodules or modules can be combined or integrated into another module, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0181] The modules or submodules described as separate components may or may not be physically separated, and the components of the modules or submodules may or may not be physical modules or submodules, that is, they may be located in one place, or they may be distributed on multiple network modules or submodules. Some or all of the modules or submodules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0182] In addition, each functional module or submodule in each embodiment of the present invention may be integrated into one processing module, or each module or submodule may exist physically separately, or two or more modules or submodules may be integrated into one module. The above-mentioned integrated modules or submodules may be implemented in the form of hardware or in the form of software functional modules or submodules.

[0183] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0184] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly by hardware, software units executed by a processor, or a combination of the two. The software units may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0185] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0186] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wind farm grid connection control method, characterized in that: The method comprises: Monitor the maximum active power that can be captured by each wind turbine in operation in the wind farm, wherein the grid-connected operation mode of each wind turbine in operation is grid-following operation or grid-building operation; According to the maximum active power that can be captured by each wind turbine in grid-following operation, the wind turbines in grid-following operation are sorted to obtain a sorting result; Obtaining the current power grid strength of the wind farm; When the grid strength is less than the target grid strength, the number of wind turbines in grid-following operation is adjusted according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result, so that the grid strength of the wind farm reaches above the target grid strength; The target grid strength is the grid strength corresponding to the minimum short-circuit ratio allowed at the grid connection point of the wind turbine generator set.

2. The method according to claim 1, characterized in that After the maximum active power that can be captured by each wind turbine operating in the monitoring wind farm, the method further comprises: According to the maximum active power that each wind turbine can capture, the grid-connected operation mode of each wind turbine is set, and the number of wind turbines in each grid-connected operation mode is obtained.

3. The method according to claim 2, characterized in that The grid-connected operation mode of each wind turbine generator set is set according to the maximum active power that each wind turbine generator set can capture, including: Compare the maximum active power that can be captured by each wind turbine with the grid-building operation power threshold and the grid-following operation power threshold; The wind turbines whose maximum active power that can be captured is greater than the grid-building operation power threshold are set to grid-building operation; Set the wind turbine generator set whose maximum active power that can be captured is less than the grid-following operation power threshold to grid-following operation; The network-following operation power threshold is equal to the difference between the network-building operation power threshold and the power hysteresis threshold.

4. The method according to any one of claims 1 to 3, characterized in that: The adjusting the number of wind turbines in grid-following operation according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result includes: According to the target grid strength, determining a first proportion of the number of wind turbines whose grid-connected operation mode is grid-configuration operation in the operating wind turbines; Determine the number N of wind turbines in grid-connected operation that need to be shut down according to the number of wind turbines in each grid-connected operation mode and the first proportion; According to the ranking result, N wind turbines in grid-following operation with the smallest maximum active power that can be captured are shut down.

5. The method according to claim 4, after determining the number N of wind turbines in grid-connected operation that need to be shut down according to the number of wind turbines in each grid-connected operation mode and the first proportion, the method further comprises: Determine the impedance characteristic curve of the wind farm according to the impedance characteristic curves of each wind turbine operating in the wind farm; When the phase of the frequency band concerned by the impedance characteristic curve of the wind farm is outside the target phase range, determining a second proportion of the number of wind turbines in grid-type operation in the operating wind turbines according to the impedance of the wind farm, the impedance of the wind turbines in grid-type operation, and the impedance of the wind turbines in grid-following operation; According to the number of wind turbines in each grid-connected operation mode and the second proportion, the number M of wind turbines in grid-connected operation mode that need to be shut down is determined; Determine the larger value max(M, N) of N and M as the number of wind turbines in grid-following operation that need to be shut down; According to the ranking result, the wind turbines in grid-following operation with the maximum (M, N) units that can capture the smallest maximum active power are shut down.

6. The method according to claim 1, characterized in that The obtaining of the power grid strength of the wind farm comprises: Control the running wind turbines to inject disturbing harmonic currents of non-characteristic sub-frequency into the access point; Collect grid voltage and grid current at the grid connection point of the operating wind turbine; Perform fast Fourier transform (FFT) analysis on the grid voltage and grid-connected current respectively, and obtain voltage FFT analysis results and current FFT analysis results respectively; Extracting the harmonic voltage component and the harmonic current component of the disturbance frequency from the voltage FFT analysis result and the current FFT analysis result respectively; Calculating the equivalent grid impedance of each wind turbine access point in operation according to the harmonic voltage component and current component of the disturbance frequency; Determine the maximum value of the equivalent grid impedances of the access points of the wind turbine generator sets as the grid equivalent impedance corresponding to the wind farm grid strength; The reciprocal of the grid equivalent impedance corresponding to the grid strength is taken, and the reciprocal is used as the grid strength of the wind farm.

7. A wind farm grid-connected control device, characterized in that: The device comprises: A monitoring module is used to monitor the maximum active power that can be captured by each wind turbine in operation in the wind farm; wherein the grid-connected operation mode of each wind turbine in operation is a grid-following operation or a grid-building operation; A sorting module is used to sort the wind turbines of the grid-following type according to the maximum active power that can be captured by each wind turbine of the grid-following type operation mode, and obtain a sorting result; An acquisition module, used to acquire the current grid strength of the wind farm; An adjustment module, for adjusting the number of wind turbines in grid-following operation according to the number of wind turbines in each grid-connected operation mode, the target grid strength and the ranking result when the grid strength is less than the target grid strength, so that the grid strength of the wind farm reaches above the target grid strength; The target grid strength is the grid strength corresponding to the minimum short-circuit ratio allowed at the grid connection point of the wind turbine generator set.

8. The device according to claim 7, characterized in that The device also includes a setting module; The setting module is used to set the grid-connected operation mode of each wind turbine set according to the maximum active power that each wind turbine set can capture, and obtain the number of wind turbine sets in each grid-connected operation mode.

9. The device according to claim 8, characterized in that The setting module is specifically used for: Compare the maximum active power that can be captured by each wind turbine with the grid-building operation power threshold and the grid-following operation power threshold; The wind turbines whose maximum active power that can be captured is greater than the grid-building operation power threshold are set to grid-building operation; Set the wind turbine generator set whose maximum active power that can be captured is less than the grid-following operation power threshold to grid-following operation; The network-following operation power threshold is equal to the difference between the network-building operation power threshold and the power hysteresis threshold.

10. An electronic device, characterized in that: The device comprises: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the wind farm grid-connected control method according to any one of claims 1 to 6 is implemented.

Images