A frequency modulation control method and device for a wind power storage power station

Abstract

The application provides a wind storage power station frequency modulation control method and device, wherein the wind storage power station frequency modulation control method comprises the following steps: obtaining power grid frequency data of a power grid connected to a wind storage power station, first group frequency modulation data of each energy storage unit in an energy storage device, and second group frequency modulation data of each wind turbine generator set in a plurality of wind turbine generator sets; determining first power released by the wind storage power station by using a droop control principle based on the power grid frequency data; further determining second power released by the energy storage device; and determining power reference values of each wind turbine generator set in the wind storage power station based on the first power released by the wind storage power station, the second power released by the energy storage device, and the second group frequency modulation data of each wind turbine generator set, so as to control the power grid frequency of the wind storage power station. The application can solve the technical problem of how to coordinate the active power released by each wind turbine generator set in the wind storage power station and the active power released by the energy storage device, and realize short-term stability of the power grid frequency connected to the wind storage power station.

Description

TECHNICAL FIELD

[0001] The embodiment of the application relates to the field of wind power grid connection technology, and particularly relates to a wind storage power station frequency modulation control method and device. BACKGROUND

[0002] Wind energy plays an important role in a new power system. With high proportion of wind power connected to the power grid, the inertia of the power system is greatly reduced, resulting in the frequency of the power grid falling when the power grid is disturbed. The wind turbine can provide active support by releasing rotational kinetic energy, but the phenomenon of over-deceleration of the wind turbine may occur, which is difficult to support the stability of the power grid frequency. At present, the above problems are solved by configuring energy storage devices in the wind storage power station. However, due to the lack of corresponding coordination strategy between the active power released by the energy storage device and the additional active power released by the wind turbine, the state of charge of the energy storage device drops too fast, resulting in insufficient active reserve in the wind storage power station to support the frequency of the power grid. Therefore, how to coordinate the additional active power released by each wind turbine in the wind storage power station and the active power released by the energy storage device to realize the short-term stability of the frequency of the power grid connected by the wind storage power station becomes a technical problem to be solved. SUMMARY

[0003] The application provides a wind storage power station frequency modulation control method and device to solve the technical problem of how to coordinate the additional active power released by each wind turbine in the wind storage power station and the active power released by the energy storage device to realize the short-term stability of the frequency of the power grid connected by the wind storage power station in the prior art.

[0004] The first aspect of the application provides a wind storage power station frequency modulation control method, the wind storage power station comprising an energy storage device and a plurality of wind turbines, the energy storage device comprising a plurality of energy storage units, comprising:

[0005] obtaining power grid frequency data of the power grid connected by the wind storage power station, a first group of frequency modulation data of each energy storage unit in the energy storage device, and a second group of frequency modulation data of each wind turbine in the plurality of wind turbines;

[0006] determining a first power released by the wind storage power station based on the power grid frequency data and using the droop control principle;

[0007] determining a second power released by the energy storage device based on the first group of frequency modulation data of all the energy storage units and the first power released by the wind storage power station;

[0008] determining a power reference value of each wind turbine in the wind storage power station based on the first power released by the wind storage power station, the second power released by the energy storage device, and the second group of frequency modulation data of each wind turbine, and the power reference value is used for frequency modulation control of the power grid frequency in the wind storage power station.

[0009] The wind storage power station frequency modulation control method provided by the embodiment of the present application comprises the following steps: obtaining frequency data of a wind storage power station connected to a power grid, first group frequency modulation data of each energy storage unit in an energy storage device, and second group frequency modulation data of each wind turbine generator in a plurality of wind turbine generators; first, determining first power released by the wind storage power station based on the power grid frequency data and using a droop control principle; second, determining second power released by the energy storage device based on the first group frequency modulation data of each energy storage unit and the first power released by the wind storage power station; and finally, determining a power reference value of each wind turbine generator in the wind storage power station based on the first power released by the wind storage power station, the second power released by the energy storage device, and the second group frequency modulation data of each wind turbine generator, and using the power reference value to perform frequency modulation control on the power grid frequency in the wind storage power station. The energy storage device and the wind turbine generator perform collaborative control on the power grid frequency in the wind storage power station, so that the wind turbine generator releases sufficient active power to achieve the purpose of stabilizing the power grid frequency of the wind storage power station connected to the power grid.

[0010] Optionally, the power grid frequency data comprises an actual value of the power grid frequency and a rated value of the power grid frequency; and the first power released by the wind storage power station is determined based on the power grid frequency data and using the droop control principle, which comprises the following steps:

[0011] If a difference between the actual value of the power grid frequency and the rated value of the power grid frequency is greater than a preset threshold, the first power released by the wind storage power station is determined based on the actual value of the power grid frequency and the rated value of the power grid frequency and using the droop control principle.

[0012] Optionally, the first power released by the wind storage power station is determined using the droop control principle, which comprises determining the first power released by the wind storage power station using the following first relationship:

[0013] ΔP WB =R(f-f n )

[0014] wherein ΔP WB is the first power released by the wind storage power station, R is a droop control coefficient, f is the actual value of the power grid frequency, and f n is the rated value of the power grid frequency.

[0015] Optionally, the first group frequency modulation data comprises a real-time state of charge, a minimum allowable value of the state of charge, an average value of the state of charge, and a maximum allowable value of the state of charge of each energy storage unit in the energy storage device; and the second power released by the energy storage device is determined based on the first group frequency modulation data of all the energy storage units and the first power released by the wind storage power station, which comprises the following steps:

[0016] determining a participation factor of each energy storage unit based on the real-time state of charge, the minimum allowable value of the state of charge, the average value of the state of charge, and the maximum allowable value of the state of charge of each energy storage unit;

[0017] determining the power released by each energy storage unit based on the participation factor of each energy storage unit and the first power released by the wind storage power station;

[0018] determining the second power released by the energy storage device based on the power released by all the energy storage units.

[0019] Optionally, the participation factor of each energy storage unit is determined based on the real-time state of charge, the minimum allowable state of charge, the average state of charge and the maximum allowable state of charge of each energy storage unit, and comprises determining the participation factor of each energy storage unit by using the following second relationship:

[0020]

[0021] wherein R B_i is the participation factor of the i th energy storage unit in the energy storage device; SOC i is the real-time state of charge value of the i th energy storage unit in the energy storage device, SOC min is the minimum allowable state of charge of the energy storage unit; SOC ave is the average state of charge of the energy storage unit; SOC max is the maximum allowable state of charge of the energy storage unit; and m is a proportional coefficient.

[0022] Optionally, the second set of frequency modulation data of each wind turbine generator comprises the actual rotor angular velocity, the minimum rotor angular velocity, the sampling time interval, the rotor angular velocity of each wind turbine generator in the previous sampling period before participating in frequency modulation and the moment of inertia of each wind turbine generator; the power reference value released by each wind turbine generator in the wind storage power station is determined based on the first power released by the wind storage power station, the second power released by the energy storage device and the second set of frequency modulation data of each wind turbine generator, and is used for frequency modulation control of the grid frequency in the wind storage power station, and comprises:

[0023] determining the power released by all the wind turbine generators based on the first power released by the wind storage power station and the second power released by the energy storage device;

[0024] determining the participation factor of each wind turbine generator based on the actual rotor angular velocity and the minimum rotor angular velocity of each wind turbine generator;

[0025] determining the power released by each wind turbine generator based on the participation factor of each wind turbine generator and the power released by all the wind turbine generators;

[0026] determining the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation based on the power released by each wind turbine generator, the sampling time interval, the rotor angular velocity of each wind turbine generator in the previous sampling period before participating in frequency modulation and the moment of inertia of each wind turbine generator;

[0027] Based on the actual rotor angular velocity of each wind turbine and the reference value of the rotor angular velocity when each wind turbine participates in frequency regulation, the reference value of the power released by each wind turbine in the wind-storage power station is determined.

[0028] Optionally, based on the actual rotor angular velocity and the minimum rotor angular velocity of each wind turbine, the participation factor of each wind turbine is determined, including by using the following third relation to determine the participation factor of each wind turbine:

[0029]

[0030] Among them, R Wi Let ω be the participation factor of the i-th wind turbine in the wind-storage power station. i Let ω be the actual rotor angular velocity of the i-th wind turbine in the wind-storage power station. min This represents the minimum rotor angular velocity of the wind turbine.

[0031] Optionally, based on the power released by each wind turbine, the sampling time interval, the rotor angular velocity of each wind turbine in the previous sampling period before participating in frequency regulation, and the moment of inertia of each wind turbine, a reference value of the rotor angular velocity of each wind turbine when participating in frequency regulation is determined, including using the following fourth relationship to determine the reference value of the rotor angular velocity of each wind turbine when participating in frequency regulation:

[0032]

[0033] Where, ω mod_i Let ω be the reference value of the rotor angular velocity of the i-th wind turbine in the wind-storage power station when it participates in frequency regulation. ref_i Let J be the rotor angular velocity of the i-th wind turbine in the wind-storage power station before it participates in frequency regulation in the previous sampling period, and let J be the moment of inertia of the wind turbine. ΔP Wi Let represent the power released by the i-th wind turbine in the wind-storage power station, and Δt be the sampling time interval.

[0034] Optionally, the wind-storage power station also includes a proportional-integral controller, wherein the second set of frequency regulation data for each wind turbine includes the rated power of the wind turbine; based on the actual rotor angular velocity of each wind turbine and the reference value of the rotor angular velocity when each wind turbine participates in frequency regulation, a reference value of the power released by each wind turbine in the wind-storage power station is determined, including:

[0035] Based on the actual rotor angular velocity of each wind turbine and the reference value of the rotor angular velocity when each wind turbine participates in frequency regulation, the initial calculated value of the power released by each wind turbine is determined by the proportional-integral controller.

[0036] Based on the initial calculated value of the active power released by each wind turbine and the rated power of the wind turbine, the reference value of the power released by each wind turbine in the wind-storage power station is determined.

[0037] The second aspect of the present application provides a frequency modulation control device for a wind storage power station, the wind storage power station comprising a storage device and a plurality of wind turbine generators, the storage device comprising a plurality of storage units, and the frequency modulation control device comprising:

[0038] a first obtaining module, configured to obtain grid frequency data of the wind storage power station connected to a power grid, first group frequency modulation data of each storage unit of the storage device, and second group frequency modulation data of each wind turbine generator of the plurality of wind turbine generators;

[0039] a first determining module, configured to determine, based on the grid frequency data, a first power released by the wind storage power station by using a droop control principle;

[0040] a second determining module, configured to determine, based on the first group frequency modulation data of all the storage units and the first power released by the wind storage power station, a second power released by the storage device;

[0041] a third determining module, configured to determine, based on the first power released by the wind storage power station, the second power released by the storage device, and the second group frequency modulation data of each wind turbine generator, a power reference value of each wind turbine generator of the wind storage power station, for frequency modulation control of the grid frequency of the wind storage power station.

[0042] The functions performed by the components of the frequency modulation control device for the wind storage power station provided by the present application have been applied in any of the method embodiments of the first aspect, and thus will not be described again here. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0044] Figure 1 a flowchart of a frequency modulation control method for a wind storage power station provided by an embodiment of the present application;

[0045] Figure 2 a structural schematic diagram of a frequency modulation control method for a wind storage power station provided by an embodiment of the present application;

[0046] Figure 3 a structural schematic diagram of a frequency modulation control method for a wind storage power station provided by an embodiment of the present application;

[0047] Figure 4 a structural schematic diagram of a frequency modulation control method for a wind storage power station provided by an embodiment of the present application;

[0048] Figure 5A wind storage power station frequency modulation control method result schematic diagram provided by an embodiment of the present application is shown in FIG. 1.

[0049] Figure 6 A wind storage power station frequency modulation control method result schematic diagram provided by an embodiment of the present application is shown in FIG. 1.

[0050] Figure 7 A wind storage power station frequency modulation control method result schematic diagram provided by an embodiment of the present application is shown in FIG. 1.

[0051] Figure 8 A wind storage power station frequency modulation control device structure schematic diagram provided by an embodiment of the present application is shown in FIG. 1. DETAILED DESCRIPTION

[0052] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without any creative work fall within the protection scope of the present disclosure.

[0053] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood as the common meanings thereof by those of ordinary skill in the art to which the present disclosure belongs. The similar words such as "one", "a" or "the" used in the present disclosure also do not represent the quantity limitation, but represent that there is at least one. The similar words such as "include" or "contain" mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects.

[0054] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0055] For the technical problems mentioned in the background art, the embodiments of the present application provide a wind storage power station frequency modulation control method, as shown in FIG. 1. As shown in FIG. 1, the wind storage power station frequency modulation control method comprises the following steps. Figure 1 Figure 2 ​As shown, the method is mainly applied to the scene that the wind power access system is disturbed and the frequency of the wind power grid connection point is reduced. As known from the background art, when the wind power access system is disturbed and the frequency of the wind power grid connection point is reduced, the wind turbine can provide active support by releasing rotational kinetic energy, but the phenomenon of over-speed reduction of the wind turbine may occur, and it is difficult to support the stability of the grid frequency. The above problem can be solved by configuring an energy storage device inside the wind farm to form a wind storage power station, so the wind storage power station in the embodiment of the application at least includes a wind turbine and an energy storage device. Unlike traditional generators, the speed of the doubly-fed wind turbine is decoupled from the grid frequency, and it usually works at the maximum power tracking point, lacks rotational backup, and is difficult to support the stability of the grid frequency. Even if the energy storage device is provided in the grid system, the energy storage device contains multiple energy storage units, but due to the lack of corresponding coordination strategy of the active power released by the multiple energy storage units in the energy storage device and the active power released by the wind turbine, the state of charge of the energy storage unit in the energy storage device may drop too fast, resulting in insufficient active backup in the wind storage power station to support the grid frequency. In order to avoid this situation, the embodiment of the application can coordinate the active power released by the multiple wind turbines in the wind storage power station and the active power released by the multiple energy storage units in the energy storage device through the following method steps, and the specific implementation process is described as follows:

[0056] In step S110, the grid frequency data of the wind storage power station connected to the grid, the first group of frequency modulation data of each energy storage unit in the energy storage device, and the second group of frequency modulation data of each wind turbine in the multiple wind turbines are obtained.

[0057] Specifically, the frequency data of the wind storage power station connected to the grid can include the actual value of the grid frequency and the rated value of the grid frequency. The first group of frequency modulation data of each energy storage unit in the energy storage device can at least include the real-time state of charge of each energy storage unit in the energy storage device, the minimum allowable value of the state of charge, the average value of the state of charge, and the maximum allowable value of the state of charge. The second group of frequency modulation data of each wind turbine can at least include the actual rotor angular velocity of each wind turbine in the wind storage power station and the minimum rotor angular velocity. The above data acquisition method belongs to the prior art, and will not be described here. Those skilled in the art can obtain it by any known method, which is not limited here.

[0058] In step S120, based on the grid frequency data, the first power released by the wind storage power station is determined by using the droop control principle.

[0059] Specifically, the droop control principle belongs to the prior art, and thus will not be explained in detail here. The first power in the embodiment can refer to additional active power, i.e., the additional active power that needs to be released by the wind and storage power station in the process of stabilizing the grid frequency. In an optional implementation, the grid frequency data at least includes an actual grid frequency value and a rated grid frequency value, and the first power is taken as an example of the additional active power. Based on the grid frequency data, the additional active power released by the wind and storage power station is determined by using the droop control principle, and specific implementation can be achieved by referring to the following method, including the following method steps:

[0060] In step S210, if the difference between the actual grid frequency value and the rated grid frequency value is greater than a preset threshold value, the first power released by the wind and storage power station is determined by using the droop control principle based on the actual grid frequency value and the rated grid frequency value.

[0061] Specifically, the preset threshold value can be determined by a person skilled in the art according to the actual working condition of the wind and storage power station, and is not limited here. It is determined whether the wind turbine and the energy storage device need to support the wind and storage power station grid frequency in the short term. When the grid frequency drop value is less than the preset threshold value, the wind turbine and the energy storage device do not need to support the wind and storage power station frequency in the short term; when the grid frequency drop value is greater than the preset threshold value, the wind turbine and the energy storage device need to support the wind and storage power station grid frequency in the short term.

[0062] For example, taking the rated grid frequency value as 100 Hz and the preset threshold value as 30 Hz as an example. When the actual grid frequency value is obtained as 80 Hz, the grid frequency drop is 20 Hz, which is less than 30 Hz, so the wind turbine and the energy storage device do not need to support the wind and storage power station frequency in the short term. When the actual grid frequency value is obtained as 60 Hz, the grid frequency drop is 40 Hz, which is greater than 30 Hz, so the wind turbine and the energy storage device need to support the wind and storage power station grid frequency in the short term.

[0063] Specifically, as an optional implementation, the additional active power released by the wind and storage power station is determined by using the following first relationship:

[0064] ΔP WB =R(f-f n )

[0065] wherein, ΔP WB is the additional active power released by the wind and storage power station, R is a droop control coefficient, f is the actual grid frequency value, and f n is the rated grid frequency value.

[0066] In step S130, the second power released by the energy storage device is determined based on the first group of frequency modulation data of all the energy storage units and the first power released by the wind and storage power station.

[0067] Specifically, the second power in the embodiment can refer to active power, i.e., active power that needs to be released by the energy storage device in the process of stabilizing the grid frequency. In an optional embodiment, taking the active power as an example, the first group of frequency modulation data at least includes a real-time state of charge of each energy storage unit in the energy storage device, a minimum allowable value of the state of charge, an average value of the state of charge, and a maximum allowable value of the state of charge. The determination of the active power that should be released by the energy storage device can be specifically implemented in the following manner, including the following method steps:

[0068] In step S410, a participation factor of each energy storage unit is determined based on the real-time state of charge, the minimum allowable value of the state of charge, the average value of the state of charge, and the maximum allowable value of the state of charge of each energy storage unit.

[0069] Specifically, in an optional embodiment, the participation factor of each energy storage unit is determined by using a second relationship, which is as follows:

[0070]

[0071] wherein, R B_i is the participation factor of the i th energy storage unit in the energy storage device; SOC i is a real-time state of charge value of the i th energy storage unit in the energy storage device, SOC min is the minimum allowable value of the state of charge of the energy storage unit; SOC ave is the average value of the state of charge of the energy storage unit; SOC max is the maximum allowable value of the state of charge of the energy storage unit; and m is a proportional coefficient, and different m values are selected according to different application scenarios. It should be noted that the energy storage units configured in the wind storage power station in the embodiment are required to be in a simultaneous discharging state when participating in the frequency modulation of the grid system, so as to avoid that a part of the energy storage units charges another part of the energy storage units, thereby affecting the service life of the energy storage.

[0072] In step S420, the power released by each energy storage unit is determined based on the participation factor of each energy storage unit and the first power released by the wind storage power station.

[0073] Specifically, the power in the embodiment can refer to active power. In an optional embodiment, taking the active power as an example. The active power that should be released by each energy storage unit is determined by using a fifth relationship, which is as follows:

[0074]

[0075] wherein, ΔP B_i is the active power that should be released by the i th energy storage unit in the energy storage device, N represents the number of energy storage units in the energy storage device, R B_i is the participation factor of the i th energy storage unit in the energy storage device, and ΔP WBThis represents the additional active power that the wind-storage power station should release. When energy storage devices need to release active power, energy storage units with a larger state of charge have a larger participation factor. The final release power of an energy storage unit is the ratio of its participation factor to the participation factors of all energy storage units. Multiplying this ratio by the additional active power that the wind-storage power station should release gives the active power that each energy storage unit should release. The calculation is simple, fast, and efficient.

[0076] As an optional embodiment, the first set of frequency modulation data also includes the rated active power of each energy storage unit; after determining the active power to be released by each energy storage unit using the following fifth relation, the method further includes determining the active power to be released by each energy storage unit using the following sixth relation:

[0077] ΔP B_i =min(ΔP) B_i ,P B_rate )

[0078] Among them, P B_rate This refers to the rated active power of the energy storage unit in the energy storage device.

[0079] Step S430: Determine the second power released by the energy storage device based on the power released by all energy storage units.

[0080] Specifically, in an optional embodiment, the active power to be released by the energy storage device is determined using the following seventh relation:

[0081]

[0082] Wherein, ΔP B N represents the active power that the energy storage device should release, and N represents the number of energy storage units in the energy storage device.

[0083] Step S140: Based on the first power released by the wind-storage power station, the second power released by the energy storage device, and the second set of frequency regulation data for each wind turbine, determine the reference value of the power released by each wind turbine in the wind-storage power station, which is used to perform frequency regulation control on the grid frequency in the wind-storage power station.

[0084] Specifically, in one optional embodiment, taking the second set of frequency regulation data for each wind turbine as an example, which includes the actual rotor angular velocity, minimum rotor angular velocity, sampling time interval, rotor angular velocity of each wind turbine in the sampling period before participating in frequency regulation, and moment of inertia of each wind turbine, the determination of the additional active power released by each wind turbine in the wind-storage power station can be implemented as follows, including the following steps:

[0085] Step S610: Based on the first power released by the wind-storage power station and the second power released by the energy storage device, determine the power released by all wind turbine units.

[0086] Specifically, in an optional embodiment, the additional active power that all wind turbines should release is determined by using the following sixth relationship:

[0087] ΔP W = ΔP WB - ΔP B

[0088] wherein ΔP W is the additional active power that all wind turbines should release, ΔP WB is the additional active power that the wind storage power station should release, and ΔP B is the active power that the energy storage device should release.

[0089] Step S620, based on the actual rotor angular velocity of each wind turbine and the minimum rotor angular velocity, determine the participation factor of each wind turbine.

[0090] Specifically, in an optional embodiment, the participation factor of each wind turbine is determined by using the following third relationship:

[0091]

[0092] wherein R Wi is the participation factor of the i-th wind turbine in the wind storage power station, ω i is the actual rotor angular velocity of the i-th wind turbine in the wind storage power station, and ω min is the minimum rotor angular velocity of the wind turbine. The participation factor of the wind turbine is calculated according to the rotor angular velocity of the wind turbine, and the greater the rotor angular velocity of the wind turbine, the greater the participation factor of the wind turbine.

[0093] Exemplarily, there are two wind turbines in a wind storage power station, wherein the rotational speed of the wind turbine 1 is high, and the active power generated by the wind turbine 1 is large; the rotational speed of the wind turbine 2 is small, and the active power generated by the wind turbine 2 is small. In essence, the wind turbine 1 with high rotational speed also has high rotor kinetic energy, and the active power value that can be used for frequency regulation at the moment is large. If the wind power access system is disturbed, the grid frequency drops suddenly, and the wind turbine needs to participate in the grid frequency support according to the set rules, requiring the wind turbine with high rotor angular velocity to release more rotor kinetic energy at the moment, and the wind turbine with small rotor angular velocity to release a small amount of rotor kinetic energy to support the grid frequency, thereby avoiding the wind turbine with low rotor angular velocity from stalling and being off-grid due to excessive active power generation.

[0094] Step S630, based on the participation factor of each wind turbine and the power released by all wind turbines, determine the power released by each wind turbine.

[0095] Specifically, the power in the embodiment can be the additional active power that each wind turbine generator should release. In an optional embodiment, taking the power released by each wind turbine generator as the additional active power that should be released, the additional active power that each wind turbine generator should release is determined by using the following ninth relationship:

[0096] ΔP Wi = Wi ΔP W

[0097] wherein, ΔP Wi is the additional active power that the i th wind turbine generator should release, R Wi is the participation factor of the i th wind turbine generator, ΔP W is the additional active power that all wind turbine generators should release.

[0098] In step S640, based on the power released by each wind turbine generator, the sampling time interval, the rotor angular velocity of each wind turbine generator before participating in frequency modulation in a sampling period, and the moment of inertia of each wind turbine generator, the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation is determined.

[0099] Specifically, in an optional embodiment, the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation is determined by using the following fourth relationship:

[0100]

[0101] wherein, ω mod_i is the rotor angular velocity reference value of the i th wind turbine generator in the wind storage power station when participating in frequency modulation, ω ref_i is the rotor angular velocity of the i th wind turbine generator in the wind storage power station before participating in frequency modulation in a sampling period, J is the moment of inertia of the wind turbine generator, ΔP Wi is the additional active power that the i th wind turbine generator in the wind storage power station should release, and Δt is the sampling time interval.

[0102] In step S650, based on the actual rotor angular velocity of each wind turbine generator and the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation, the power reference value of each wind turbine generator in the wind storage power station is determined.

[0103] Specifically, in an optional embodiment, taking that the wind storage power station further includes a proportional integral controller and the second set of frequency modulation data of each wind turbine generator includes the rated power of the wind turbine generator as an example, the active power reference value of each wind turbine generator in the wind storage power station is determined, and specific implementation can be referred to the following method, including the following method steps:

[0104] Step S910, based on the actual rotor angular velocity of each wind turbine and the rotor angular velocity reference value of each wind turbine participating in frequency modulation, determining the initial calculated value of the power released by each wind turbine through a proportional integral controller.

[0105] Specifically, in an optional embodiment, the initial calculated value of the active power released by each wind turbine is determined by using the tenth relationship as follows:

[0106] P ref_ini_i =(k p (ω mod_i -ω i )+k i ∫(ω mod_i -ω i )dt)×ω i

[0107] wherein P ref_int_i is the initial calculated value of the active power released by each wind turbine in the wind storage power station, ω mod_i is the rotor angular velocity reference value of the i th wind turbine in the wind storage power station participating in power coordination, ω i is the actual rotor angular velocity of the i th wind turbine in the wind storage power station, k p is the proportional coefficient of the proportional integral controller, and k i is the integral coefficient of the proportional integral controller.

[0108] Step S920, determining the power reference value of each wind turbine in the wind storage power station according to the initial calculated value of the active power released by each wind turbine and the rated power of the wind turbine.

[0109] Specifically, in the embodiment, the power reference value can be an active power reference value. In an optional embodiment, the active power reference value of each wind turbine in the wind storage power station is determined by using the eleventh relationship as follows:

[0110] P ref_i =min(P ref_ini_i ,P max )

[0111] wherein P max is the rated power of the wind turbine in the wind storage power station.

[0112] In a specific example, the wind turbine is a doubly-fed wind turbine. For details, refer to FIGS. 1 and 2. Figure 2 、 Figure 3 Figure 2 ​A power coordination block diagram of the energy storage device and the doubly-fed wind turbine for jointly supporting the grid frequency. The implementation mainly calculates the active power that the energy storage device should release and the additional active power that the doubly-fed wind turbine should release, forms the corresponding control instructions, and sends the control instructions to the power control module of the energy storage device and the control module of the doubly-fed wind turbine to coordinate the power, so as to obtain the final active power reference value of the doubly-fed wind turbine. In addition, the energy storage device releases the corresponding active power according to the determined active power instruction, so as to jointly complete the short-term collaborative support for the grid frequency with the doubly-fed wind turbine. The dead zone control module determines whether the grid frequency needs to be adjusted by judging whether the grid frequency deviation Δf exceeds the frequency regulation threshold DB. When the grid frequency deviation does not exceed the frequency regulation threshold DB, it indicates that the grid frequency does not need to be adjusted. When the grid frequency deviation exceeds the frequency regulation threshold DB, it indicates that the grid frequency needs to be adjusted, at which time the additional active power that the wind storage power station should release is calculated by the droop control, so as to realize the short-term frequency support of the grid, and the specific implementation process is described in the corresponding part above, which will not be repeated here. The energy storage device power control module calculates the participation factor of each energy storage unit in the energy storage device and the active power that should be released according to the total additional active power that the wind storage power station should release calculated by the frequency droop control module and the state of charge of each energy storage unit in the energy storage device. The specific implementation process is described in the corresponding part above. The rotor speed controller is shown in Figure 3 The PQ control, inverter control and rotor-side inverter control in the energy storage device control are known to those skilled in the art, which will not be repeated here. Figure 3 The maximum power point tracking (MPPT) is known to those skilled in the art, and the active power P W The rotor speed reference value ω mod_i of the i-th doubly-fed wind turbine participating in power coordination is determined in the normal working state, which will not be repeated here. The rotor speed reference value ω i of the i-th doubly-fed wind turbine participating in power coordination is subtracted from the actual rotor speed ω pref_i of the i-th doubly-fed wind turbine, and the difference is sent to a proportional integral (PI) module to obtain the torque reference value T pref_i of the i-th doubly-fed wind turbine. The torque reference value T i of the i-th doubly-fed wind turbine is multiplied by the actual rotor speed ω pref_ini_i of the i-th doubly-fed wind turbine to obtain the initial active power reference value P max of the i-th doubly-fed wind turbine, and the result is input to a limiting module. The maximum value P max of the limiting module is the maximum active power allowed to be output. If the value is less than P ref_i , the active power reference value P pref_ini_i is equal to P max ; if it is greater than P ref_i=Pmax, finally obtaining the real-time active power reference value P of the i-th doubly-fed wind turbine. ref_i .

[0113] The frequency regulation control method for wind-storage power stations provided in this invention acquires the frequency data of the wind-storage power station connected to the grid, the first set of frequency regulation data for each energy storage unit in the energy storage device, and the second set of frequency regulation data for each wind turbine in multiple wind turbine units. First, based on the grid frequency data, the first power released by the wind-storage power station is determined using the droop control principle. Second, based on the first set of frequency regulation data for each energy storage unit and the first power released by the wind-storage power station, the second power released by the energy storage device is determined. Finally, based on the first power released by the wind-storage power station, the second power released by the energy storage device, and the second set of frequency regulation data for each wind turbine unit, a reference value for the power to be released by each wind turbine unit in the wind-storage power station is determined, which is used to perform frequency regulation control on the grid frequency in the wind-storage power station. This achieves coordinated control of the grid frequency in the wind-storage power station by the energy storage device and the wind turbine units, thereby enabling the wind turbine units to release sufficient active power to achieve stable grid frequency connection for the wind-storage power station. This avoids the risks of excessive drop in the state of charge of the energy storage device and excessively rapid decrease in the rotor angular velocity of the wind turbine units, ensuring the stability of the grid frequency.

[0114] To verify the effectiveness of the technical solution of the present invention, in a specific embodiment as follows: Figure 4 As shown, the wind-storage power station consists of a 200MW doubly-fed wind turbine and a 40MW / 20MWh energy storage device, which comprises two energy storage units. The conventional generator set in the power grid has a capacity of 500MVA. A 400MW load 1 is connected to the generator node, and a 40MW load 2 is connected to the wind-storage power station's grid connection point. At 10 seconds, load 2 suddenly increases by 20MW to verify the effectiveness of the frequency support method proposed in this patent. Figure 5 The schematic diagram of power grid frequency change provided for the example of the present invention shows that when there is no energy storage device and wind turbine to jointly support the frequency, the lowest frequency drops to 49.76Hz and oscillates significantly. After providing joint support, the lowest frequency rises to 49.9Hz and quickly stabilizes. Figure 6 , Figure 7 These figures illustrate the changes in the state of charge of the energy storage device and the rotor angular velocity of the doubly-fed induction generator (DFIG) wind turbine, respectively, in embodiments of the present invention. As shown in the figures, after implementing this technical solution, the energy storage device and the wind turbine work together to support the grid frequency, reducing the risk of excessively rapid decreases in the state of charge of the energy storage device and the rotor angular velocity of the wind turbine. Furthermore, the speed difference between wind turbines with different initial rotor angular velocities gradually decreases, avoiding excessive deceleration of the wind turbine.

[0115] Figure 8The wind storage power station frequency modulation control method and device provided by the embodiment of the present application, the wind storage power station comprises a storage device and multiple wind turbine generators, the storage device comprises multiple storage units, and the method comprises the following steps:

[0116] The first acquisition module 1010 is configured to acquire grid frequency data of the wind storage power station connected to the power grid, first group frequency modulation data of each storage unit of the storage device, and second group frequency modulation data of each wind turbine generator of the multiple wind turbine generators. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0117] The first determination module 1020 is configured to determine the first power released by the wind storage power station based on the grid frequency data and the droop control principle. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0118] The second determination module 1030 is configured to determine the second power released by the storage device based on the first group frequency modulation data of all the storage units and the first power released by the wind storage power station. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0119] The third determination module 1040 is configured to determine the power reference value of each wind turbine generator in the wind storage power station based on the first power released by the wind storage power station, the second power released by the storage device, and the second group frequency modulation data of each wind turbine generator, so as to perform frequency modulation control on the grid frequency of the wind storage power station. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0120] As an optional implementation device of the present application, the grid frequency data comprises an actual grid frequency value and a rated grid frequency value, and the first determination module 1020 comprises:

[0121] The fourth determination module is configured to determine the first power released by the wind storage power station based on the actual grid frequency value and the rated grid frequency value by using the droop control principle if the difference between the actual grid frequency value and the rated grid frequency value is greater than a preset threshold. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0122] As an optional implementation device of the present application, it comprises:

[0123] The fifth determination module is configured to determine the first power released by the wind storage power station by using the following first relationship:

[0124] ΔP WB =R(f-f n )

[0125] Wherein, ΔP WB is the first power released by the wind storage power station, R is a droop control coefficient, f is the actual grid frequency value, and f nThe grid frequency is a rated value. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0126] As an optional implementation device of the present application, the first group of frequency modulation data includes the real-time state of charge, the minimum allowable value of the state of charge, the average value of the state of charge, and the maximum allowable value of the state of charge of each energy storage unit in the energy storage device; the second determination module 1030 includes:

[0127] The sixth determination module is configured to determine the participation factor of each energy storage unit based on the real-time state of charge, the minimum allowable value of the state of charge, the average value of the state of charge, and the maximum allowable value of the state of charge of each energy storage unit. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0128] The seventh determination module is configured to determine the power released by each energy storage unit based on the participation factor of each energy storage unit and the first power released by the wind storage power station. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0129] The eighth determination module is configured to determine the second power released by the energy storage device based on the power released by all energy storage units. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0130] As an optional implementation device of the present application, the sixth determination module includes:

[0131] The ninth determination module is configured to determine the participation factor of each energy storage unit by using the following second relationship:

[0132]

[0133] wherein, R B_i is the participation factor of the i-th energy storage unit in the energy storage device; SOC i is the real-time state of charge value of the i-th energy storage unit in the energy storage device, SOC min is the minimum allowable value of the state of charge of the energy storage unit; SOC ave is the average value of the state of charge of the energy storage unit; SOC max is the maximum allowable value of the state of charge of the energy storage unit; and m is a proportional coefficient. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0134] As an optional implementation device of the present application, the second group of frequency modulation data of each wind turbine includes the actual rotor angular velocity of each wind turbine, the minimum rotor angular velocity, the sampling time interval, the rotor angular velocity of each wind turbine in the last sampling period before participating in frequency modulation, and the moment of inertia of each wind turbine; the third determination module 1040 includes:

[0135] The tenth determining module is configured to determine the power released by all wind turbines based on the first power released by the wind storage power station and the second power released by the energy storage device. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0136] The eleventh determining module is configured to determine the participation factor of each wind turbine based on the actual rotor angular velocity of each wind turbine and the minimum rotor angular velocity. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0137] The twelfth determining module is configured to determine the power released by each wind turbine based on the participation factor of each wind turbine and the power released by all wind turbines. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0138] The thirteenth determining module is configured to determine the rotor angular velocity reference value of each wind turbine when participating in frequency modulation based on the power released by each wind turbine, the sampling time interval, the rotor angular velocity of each wind turbine in the last sampling period before participating in frequency modulation, and the moment of inertia of each wind turbine. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0139] The fourteenth determining module is configured to determine the power reference value released by each wind turbine in the wind storage power station based on the actual rotor angular velocity of each wind turbine and the rotor angular velocity reference value of each wind turbine when participating in frequency modulation. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0140] As an optional implementation device of the present application, the eleventh determining module comprises:

[0141] The fifteenth determining module is configured to determine the participation factor of each wind turbine by using the following third relationship:

[0142]

[0143] wherein, R Wi is the participation factor of the i th wind turbine in the wind storage power station, ω i is the actual rotor angular velocity of the i th wind turbine in the wind storage power station, ω min is the minimum rotor angular velocity of the wind turbine. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0144] As an optional implementation device of the present application, the thirteenth determining module comprises:

[0145] The sixteenth determining module is configured to determine the rotor angular velocity reference value of each wind turbine when participating in frequency modulation by using the following fourth relationship:

[0146]

[0147] ω i,ref = ω i,ref + Δω i,ref mod_i ω i,ref = ω i,ref + Δω i,ref ref_i ω i,ref = ω i,ref + Δω i,ref Wi ΔP i = ΔP i + ΔP i

[0148] As an optional implementation device of the present application, the wind storage power station further comprises a proportional integral controller, the second group of frequency modulation data of each wind turbine includes rated power of the wind turbine; the fourteenth determination module comprises:

[0149] The seventeenth determination module is configured to determine, by the proportional integral controller, an initial calculation value of the released power of each wind turbine based on the actual rotor angular velocity of each wind turbine and the rotor angular velocity reference value of each wind turbine when participating in frequency modulation. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0150] The eighteenth determination module is configured to determine, according to the initial calculation value of the active power released by each wind turbine and the rated power of the wind turbine, a power reference value of each wind turbine in the wind storage power station. For details, refer to the description of the corresponding part in the above embodiment, which will not be repeated here.

[0151] In the description of the present specification, the description of the terms "the embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the different embodiments or examples described in the present specification and the features of the different embodiments or examples can be combined and combined by those skilled in the art without contradiction. In the present disclosure description, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0152] Obviously, the above embodiments are merely example for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and can not be enumerated. The obvious changes or variations derived from this still fall within the protection scope of the present application.

Claims

1. A method for frequency regulation control of a wind storage power station, characterized in that, The wind storage power station comprises a storage device and a plurality of wind turbine generators, the storage device comprises a plurality of storage units, and the method comprises: obtaining grid frequency data of the wind storage power station connected to a power grid, first group of frequency modulation data of each storage unit of the storage device, and second group of frequency modulation data of each wind turbine generator of the plurality of wind turbine generators; determining, based on the grid frequency data, a first power released by the wind storage power station by using a droop control principle; determining, based on the first group of frequency modulation data of all the storage units and the first power released by the wind storage power station, a second power released by the storage device; determining, based on the first power released by the wind storage power station, the second power released by the storage device, and the second group of frequency modulation data of each wind turbine generator, a power reference value of each wind turbine generator of the wind storage power station for frequency modulation control of the grid frequency of the wind storage power station; the first group of frequency modulation data comprises a real-time state of charge, a minimum allowable state of charge, an average state of charge, and a maximum allowable state of charge of each storage unit of the storage device; and the determination of the second power released by the storage device based on the first group of frequency modulation data of all the storage units and the first power released by the wind storage power station comprises: determining, based on the real-time state of charge, the minimum allowable state of charge, the average state of charge, and the maximum allowable state of charge of each storage unit, a participation factor of each storage unit; determining, based on the participation factor of each storage unit and the first power released by the wind storage power station, a power released by each storage unit; determining, based on the powers released by all the storage units, the second power released by the storage device; the determination of the participation factor of each storage unit based on the real-time state of charge, the minimum allowable state of charge, the average state of charge, and the maximum allowable state of charge of each storage unit comprises determining the participation factor of each storage unit by using a second relationship formula; wherein, is the participation factor of the i-th energy storage unit in the energy storage device; SOC i is the real-time state of charge value of the i-th energy storage unit in the energy storage device, SOC min is the minimum allowed value of the state of charge of the energy storage unit; SOC ave is the average value of the state of charge of the energy storage unit; SOC max is the maximum allowed value of the state of charge of the energy storage unit; m is a proportionality factor.

2. The method of claim 1, wherein, the grid frequency data comprises an actual grid frequency value and a rated grid frequency value; and the determination of the first power released by the wind storage power station based on the grid frequency data by using the droop control principle comprises: if a difference between the actual grid frequency value and the rated grid frequency value is greater than a preset threshold, determining the first power released by the wind storage power station based on the actual grid frequency value and the rated grid frequency value by using the droop control principle.

3. The method of claim 2, wherein, the determination of the first power released by the wind storage power station by using the droop control principle comprises determining the first power released by the wind storage power station by using a first relationship formula. wherein, R is a droop control coefficient, f is an actual value of the grid frequency, f n is a rated value of the grid frequency.

4. The method according to any one of claims 1 to 3, characterized in that, The second group of frequency modulation data of each wind turbine generator includes actual rotor angular velocity, minimum rotor angular velocity, sampling time interval, rotor angular velocity of each wind turbine generator before participating in frequency modulation, and moment of inertia of each wind turbine generator; based on the first power released by the wind storage power station, the second power released by the energy storage device, and the second group of frequency modulation data of each wind turbine generator, a power reference value of each wind turbine generator in the wind storage power station is determined for frequency modulation control of the grid frequency in the wind storage power station, including: determining the power released by all the wind turbine generators based on the first power released by the wind storage power station and the second power released by the energy storage device; determining the participation factor of each wind turbine generator based on the actual rotor angular velocity and the minimum rotor angular velocity of each wind turbine generator; determining the power released by each wind turbine generator based on the participation factor of each wind turbine generator and the power released by all the wind turbine generators; determining the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation based on the power released by each wind turbine generator, the sampling time interval, the rotor angular velocity of each wind turbine generator before participating in frequency modulation, and the moment of inertia of each wind turbine generator; determining the power reference value of each wind turbine generator in the wind storage power station based on the actual rotor angular velocity of each wind turbine generator and the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation.

5. The method of claim 4, wherein, The determination of the participation factor of each wind turbine generator based on the actual rotor angular velocity and the minimum rotor angular velocity of each wind turbine generator includes determining the participation factor of each wind turbine generator by using the following third relationship: wherein, ωi is the participation factor of the i-th wind turbine in the wind storage plant, i ωi is the actual rotor angular speed of the i-th wind turbine in the wind storage plant, min ωmin is the minimum rotor angular speed of the wind turbine.

6. The method of claim 4, wherein, The determination of the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation based on the power released by each wind turbine generator, the sampling time interval, the rotor angular velocity of each wind turbine generator before participating in frequency modulation, and the moment of inertia of each wind turbine generator includes determining the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation by using the following fourth relationship: wherein ω mod_i is the rotor angular speed reference value of the i-th wind turbine participating in frequency regulation in the wind storage power station, ω ref_i is the rotor angular speed of the i-th wind turbine before participating in frequency regulation in the wind storage power station in the previous sampling period, J is the rotational inertia of the wind turbine, is the released power of the i-th wind turbine in the wind storage power station, t is the sampling time interval.

7. The method of claim 4, wherein, The wind storage power station further includes a proportional-integral controller, and the second group of frequency modulation data of each wind turbine generator includes rated power of the wind turbine generator; the determination of the power reference value of each wind turbine generator in the wind storage power station based on the actual rotor angular velocity of each wind turbine generator and the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation includes: determining the initial calculation value of the power released by each wind turbine generator through the proportional-integral controller based on the actual rotor angular velocity of each wind turbine generator and the rotor angular velocity reference value of each wind turbine generator when participating in frequency modulation; determining the power reference value of each wind turbine generator in the wind storage power station according to the initial calculation value of the active power released by each wind turbine generator and the rated power of the wind turbine generator.

8. A frequency modulation control device for a wind storage power station, characterized by comprising: The wind storage power station includes an energy storage device and multiple wind turbine generators, the energy storage device includes multiple energy storage units, and the device includes: The first obtaining module is configured to obtain grid frequency data of a grid to which a wind storage power station is connected, first group of frequency modulation data of each energy storage unit in an energy storage device, and second group of frequency modulation data of each wind turbine generator in a plurality of wind turbine generators in the wind storage power station; The first determining module is configured to determine, based on the grid frequency data, a first power released by the wind storage power station by using a droop control principle; The second determining module is configured to determine, based on the first group of frequency modulation data of all the energy storage units and the first power released by the wind storage power station, a second power released by the energy storage device; The third determining module is configured to determine, based on the first power released by the wind storage power station, the second power released by the energy storage device, and the second group of frequency modulation data of each wind turbine generator, a power reference value of each wind turbine generator in the wind storage power station, for frequency modulation control of a grid frequency in the wind storage power station; The first group of frequency modulation data includes real-time state of charge, minimum allowable value of state of charge, average value of state of charge, and maximum allowable value of state of charge of each energy storage unit in the energy storage device; and the determination of the second power released by the energy storage device based on the first group of frequency modulation data of all the energy storage units and the first power released by the wind storage power station includes: determining, based on the real-time state of charge, the minimum allowable value of state of charge, the average value of state of charge, and the maximum allowable value of state of charge of each energy storage unit, a participation factor of each energy storage unit; determining, based on the participation factor of each energy storage unit and the first power released by the wind storage power station, a power released by each energy storage unit; determining, based on the powers released by all the energy storage units, the second power released by the energy storage device; The determination of the participation factor of each energy storage unit based on the real-time state of charge, the minimum allowable value of state of charge, the average value of state of charge, and the maximum allowable value of state of charge of each energy storage unit includes determining the participation factor of each energy storage unit by using a second relationship as follows: wherein, is the participation factor of the i-th energy storage unit in the energy storage device; SOC i is the real-time state of charge value of the i-th energy storage unit in the energy storage device, SOC min is the minimum allowed value of the state of charge of the energy storage unit; SOC ave is the average value of the state of charge of the energy storage unit; SOC max is the maximum allowed value of the state of charge of the energy storage unit; m is a proportionality coefficient.

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