Voltage regulation method and device, storage medium and computer program product

Abstract

The invention discloses a voltage regulation method and device, a storage medium and a computer program product, and relates to the field of wind power generation, the voltage regulation method comprises the steps that the voltage of a land power grid is determined through a target converter, one end of the target converter is connected with the land power grid, and the other end of the target converter is connected with an offshore wind plant; the target converter is used for converting and transmitting electric power between the offshore wind plant and the land power grid; under the condition that the voltage deviates from the rated voltage, determining a self-adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter, determining the first reactive power of the land power grid according to the self-adaptive droop coefficient, and determining the self-adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind plant, determining a second reactive power of the wind turbine according to the adaptive gain; adjusting the voltage of the land grid according to the first reactive power and the second reactive power.

Description

Technical Field

[0001] The present application relates to the field of wind power generation, and in particular to a voltage regulation method and device, a storage medium, and a computer program product. Background Art

[0002] With the global emphasis on and utilization of renewable energy, wind power generation, as an important component of clean energy, has been expanding in scale, and offshore wind farms have developed rapidly in recent years. The grid connection of wind farms, that is, the connection of wind turbines to the grid through power conversion equipment, has put forward higher requirements on the stability of grid voltage.

[0003] In traditional wind farm grid-connected control strategies, static preset control parameters are often used, such as fixed droop gain or constant voltage control. However, the preset control parameters cannot be dynamically adjusted according to real-time wind speed changes and grid voltage fluctuations, resulting in the voltage support capacity of the wind farm being limited when the wind speed is high or the grid voltage is abnormal, and it cannot effectively respond to grid demand, thus affecting the stability of the power system.

[0004] Regarding the related technologies, the traditional wind farm grid-connected control strategy adopts preset control parameters and cannot dynamically adjust the grid voltage, resulting in the problem of power system instability. No effective solution has been proposed so far.

[0005] Therefore, it is necessary to improve the related technology to overcome the above-mentioned defects in the related technology. Summary of the invention

[0006] The embodiments of the present application provide a voltage regulation method and device, a storage medium and a computer program product to at least solve the problem in the related art that the traditional wind farm grid-connected control strategy adopts preset control parameters and cannot dynamically adjust the grid voltage, resulting in instability of the power system.

[0007] According to one aspect of an embodiment of the present application, a voltage regulation method is provided, comprising: determining the voltage of a land power grid through a target converter, wherein one end of the target converter is connected to the land power grid and the other end is connected to an offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid; when the voltage deviates from the rated voltage, determining an adaptive droop coefficient of the land power grid according to a current first reactive capacity of the target converter, and determining a first reactive power of the land power grid according to the adaptive droop coefficient, and determining an adaptive gain of the wind turbine according to a current second reactive capacity of the wind turbine in the offshore wind farm, and determining a second reactive power of the wind turbine according to the adaptive gain; and regulating the voltage of the land power grid according to the first reactive power and the second reactive power.

[0008] In an exemplary embodiment, determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter includes: determining the first reactive capacity Q according to the following formula: max : Among them, S max is the maximum transmission capacity of the target converter, P is the active power currently transmitted by the target converter to the land power grid; the adaptive droop coefficient K of the land power grid is determined according to the following formula: Q (P): Among them, C is the relevant proportional coefficient.

[0009] In an exemplary embodiment, determining the first reactive power of the land power grid according to the adaptive droop coefficient includes: determining the first reactive power ΔQ according to the following formula: ΔQ=K Q (P)(V s_ref -V s ), where K Q (P) is the adaptive droop coefficient of the land power grid, V s_ref is the reference value of the voltage of the target converter connected to the land grid, V S is the measured value of the voltage of the land grid connected to the target converter, -Q max ≤ΔQ≤Q max , Q max is the first reactive capacity.

[0010] In an exemplary embodiment, determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm includes: determining the active power P of the wind turbine according to the following formula: t :P t =k opt v i 3 , where k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm; the second reactive capacity Q is determined according to the following formula W : Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine; the adaptive gain AG is determined according to the following formula i (v i ): Wherein, C is a positive proportional coefficient between the adaptive gain and the second reactive capacity, and i is a positive integer.

[0011] In an exemplary embodiment, determining the second reactive power of the wind turbine according to the adaptive gain includes: determining the second reactive power ΔQ according to the following formula: i :ΔQ i =-AG i (v i )(V sys -V nom ), where i is a positive integer, AG i (v i ) is the adaptive gain, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm.

[0012] In an exemplary embodiment, before determining the adaptive gain of the wind turbine through the current second reactive capacity of the wind turbine in the offshore wind farm, the method also includes: determining the third reactive power of the wind turbine according to the fixed droop gain of the wind turbine; and determining a positive proportional coefficient of the adaptive gain and the second reactive capacity according to the third reactive power and the second reactive power.

[0013] In an exemplary embodiment, before determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, the method further includes: determining the third reactive power ΔQ according to the following formula: t : Wherein, n is the number of wind turbines, R is the equivalent impedance at the grid connection point of the offshore wind farm, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm; determining the proportional coefficient C of the adaptive gain and the second reactive capacity according to the third reactive power and the second reactive power: Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine, k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm.

[0014] According to another aspect of an embodiment of the present application, a voltage regulation device is also provided, including: a first determination module, used to determine the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid and the other end is connected to an offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid; a second determination module, used to determine the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter when the voltage deviates from the rated voltage, and determine the first reactive power of the land power grid according to the adaptive droop coefficient, and determine the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, and determine the second reactive power of the wind turbine according to the adaptive gain; an adjustment module, used to adjust the voltage of the land power grid according to the first reactive power and the second reactive power.

[0015] According to another aspect of the embodiments of the present application, a computer-readable storage medium is provided, in which a computer program is stored, wherein the computer program is configured to execute the above-mentioned voltage regulation method when running.

[0016] According to another aspect of the embodiments of the present application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the voltage regulation method through the computer program.

[0017] According to another aspect of the embodiments of the present application, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps of the method described in each embodiment of the present application are implemented.

[0018] Through this application, when the voltage of the land power grid deviates from the rated voltage, the adaptive droop coefficient of the land power grid is determined according to the current first reactive capacity of the target converter, and the first reactive power of the land power grid is determined according to the adaptive droop coefficient, and the adaptive gain of the wind turbine is determined according to the current second reactive capacity of the wind turbine in the offshore wind farm, and the second reactive power of the wind turbine is determined according to the adaptive gain; the voltage of the land power grid is adjusted according to the first reactive power and the second reactive power. This solves the problem in the related art that the traditional wind farm grid-connected control strategy adopts preset control parameters and cannot dynamically adjust the grid voltage, resulting in unstable power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] In order to more clearly illustrate the embodiments of the present application 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 is a hardware structure block diagram of a voltage regulation method according to an embodiment of the present application;

[0022] Figure 2 is a flow chart of a voltage regulation method according to an embodiment of the present application;

[0023] Figure 3 is a topological structure diagram of a target converter of a voltage regulation method according to an embodiment of the present application;

[0024] Figure 4 is a system structure diagram of a voltage regulation method according to an embodiment of the present application;

[0025] Figure 5 is a schematic diagram of reactive power-voltage droop characteristics of a voltage regulation method according to an embodiment of the present application;

[0026] Figure 6 is a reactive power-voltage droop characteristic control block diagram of a voltage regulation method according to an embodiment of the present application;

[0027] Figure 7 is a second reactive power range diagram of a voltage regulation method according to an embodiment of the present application;

[0028] Figure 8 is a block diagram of an adaptive gain control strategy of a voltage regulation method according to an embodiment of the present application;

[0029] Fig. 9 is a first simulation diagram of a second reactive power of a voltage regulation method according to an embodiment of the present application;

[0030] Fig.10 is a second simulation diagram of a second reactive power of a voltage regulation method according to an embodiment of the present application;

[0031] Fig.11 is a third simulation diagram of a second reactive power of a voltage regulation method according to an embodiment of the present application;

[0032] Fig.12 It is a structural block diagram of a voltage regulation device according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] The method embodiments provided in the embodiments of the present application can be executed in a target converter or a similar computing device. Taking the operation on the target converter as an example, Figure 1 1 is a hardware structure block diagram of a target converter of a voltage regulation method according to an embodiment of the present application. Figure 1 As shown, the target converter may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor (Central Processing Unit, MCU) or a programmable logic device (Field Programmable Gate Array, FPGA)) and a memory 104 for storing data, wherein the above-mentioned target converter may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the target converter. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0036] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the voltage regulation method in the embodiment of the present application. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the target converter via a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0037] A wireless network provided by a communication provider of the target inverter. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0038] In this embodiment, a voltage regulation method is provided, which is applied to the above-mentioned target converter. Figure 2 is a flow chart of a voltage regulation method according to an embodiment of the present application, such as Figure 2 As shown, the process includes the following steps:

[0039] Step S202, determining the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid, and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid;

[0040] Step S204, when the voltage deviates from the rated voltage, determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter, and determining the first reactive power of the land power grid according to the adaptive droop coefficient, and determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, and determining the second reactive power of the wind turbine according to the adaptive gain;

[0041] Step S206: adjusting the voltage of the land power grid according to the first reactive power and the second reactive power.

[0042] Through the above steps, the voltage of the land power grid is determined by the target converter, wherein one end of the target converter is connected to the land power grid and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid; when the voltage deviates from the rated voltage, the adaptive droop coefficient of the land power grid is determined according to the current first reactive capacity of the target converter, and the first reactive power of the land power grid is determined according to the adaptive droop coefficient, and the adaptive gain of the wind turbine is determined according to the current second reactive capacity of the wind turbine in the offshore wind farm, and the second reactive power of the wind turbine is determined according to the adaptive gain; the voltage of the land power grid is adjusted according to the first reactive power and the second reactive power. Thus, the problem that the traditional wind farm grid-connected control strategy in the related art adopts preset control parameters and cannot dynamically adjust the grid voltage, resulting in instability of the power system, is solved.

[0043] In an exemplary embodiment, determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter includes: determining the first reactive capacity Q according to the following formula: max : Among them, S max is the maximum transmission capacity of the target converter, P is the active power currently transmitted by the target converter to the land power grid; the adaptive droop coefficient K of the land power grid is determined according to the following formula: Q (P): Among them, C is the relevant proportional coefficient.

[0044] The reactive power capacity that the converter can provide is determined according to the principle of energy conservation. The maximum transmission capacity S of the modular multilevel matrix converter (M3C) (i.e. the target converter) is max Includes active power P and reactive power Q max Since active and reactive power are mutually exclusive from the perspective of energy conservation, that is, increasing reactive power will reduce the available capacity of active power, the formula is obtained by starting from the maximum transmission capacity S max Subtract the active power P from the remaining reactive power capacity Q max Then, for the remaining power S max -p(t) is square rooted to obtain the first reactive capacity Q max .

[0045] In an embodiment, the adaptive droop coefficient K Q(P) is adaptively adjusted according to the current active power transmission of the M3C converter. This means that the droop coefficient is no longer fixed, but will be dynamically adjusted according to the real-time active power output of the M3C converter. The benefit of this adaptive control strategy is that when the active power transmission of the M3C converter approaches the maximum value, the reactive power regulation capability will be reduced and the voltage of the land grid will become unstable. By adjusting the adaptive droop coefficient K Q (P) can maximize the use of the reactive power regulation capability of the M3C converter, especially when wind speed fluctuations cause active power changes, and can provide stable voltage support.

[0046] In an exemplary embodiment, determining the first reactive power of the land power grid according to the adaptive droop coefficient includes: determining the first reactive power ΔQ according to the following formula: ΔQ=K Q (P)(V s_ref -V s ), where K Q (P) is the adaptive droop coefficient of the land power grid, V s_ref is the reference value of the voltage of the target converter connected to the land grid, V S is the measured value of the voltage of the land grid connected to the target converter, -Q max ≤ΔQ≤Q max , Q max is the first reactive capacity.

[0047] In traditional droop control, the droop coefficient is fixed. However, in this embodiment, the adaptive droop coefficient K Q (P) is dynamically adjusted according to the active power P currently transmitted by the M3C converter. When the active power P is low, the M3C converter has a large margin in transmission capacity and can provide more reactive power support, so K Q (P) will be set larger; on the contrary, when the active power P is close to the maximum value, the capacity of the M3C converter for reactive power regulation will be reduced. In order to maintain the stable operation of the system, K Q (P) will decrease. At the same time, in the design and operation of the M3C converter, the output of its active power and reactive power cannot reach the maximum value at the same time, and a trade-off must be made between the two. When P is small, Q max The M3C converter has a larger reactive power regulation capability; when P is close to the maximum value, Q max Reduced, reactive power regulation capability is limited.

[0048] In an exemplary embodiment, determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm includes: determining the active power P of the wind turbine according to the following formula:t :P t =k opt v i 3 , where k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm; the second reactive capacity Q is determined according to the following formula W : Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine; the adaptive gain AG is determined according to the following formula i (v i ): Wherein, C is a positive proportional coefficient between the adaptive gain and the second reactive capacity, and i is a positive integer.

[0049] P t =k opt v i 3 The sixth power relationship between wind turbine active power and wind speed is described, which means that when wind speed increases, wind turbines can capture more wind energy and the output active power increases accordingly. However, the relationship between wind speed and active power is not linear, but follows a parabolic curve, which reflects the physical principles of wind turbine design and the efficiency of converting wind power into electrical energy.

[0050] exist middle, Indicates the maximum capacity of the wind turbine converter, P t 2 is the square of the current active power of the wind turbine. Minus And take the square root of the result to get the second reactive capacity Q under the current conditions W This formula shows that in actual operation, when the active power of the wind turbine increases, the reactive capacity it can provide will decrease accordingly, and vice versa. This dynamic adjustment mechanism ensures that the wind turbine converter can maintain stable operation under different wind speeds and grid demands, while providing the necessary reactive support to maintain grid voltage stability.

[0051] In traditional control strategies, the gain is usually fixed, but in this embodiment, the adaptive gain AG i (v i ) According to the wind speed v i Dynamic adjustment to optimize the reactive power output of wind turbines. i (v i) is related to the rated capacity of the wind turbine, wind speed and the operating status of other wind turbines in the wind farm. When the wind speed changes, the reactive power demand of the power grid will also change. The adaptive gain AG i (v i ) can ensure that the reactive power output of the wind turbine responds to these changes and can keep the grid voltage stable even when the wind speed changes rapidly.

[0052] In an exemplary embodiment, determining the second reactive power of the wind turbine according to the adaptive gain includes: determining the second reactive power ΔQ according to the following formula: i :ΔQ i =-AG i (v i )(V sys -V nom ), where i is a positive integer, AG i (v i ) is the adaptive gain, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm.

[0053] The second reactive power ΔQ i In fact, the adaptive gain AG is determined by i (v i ) and voltage deviation V sys -V nom The adaptive gain AG i (v i ) is set according to the operating status of the wind turbine (such as input wind speed) and the maximum reactive power capacity. Its purpose is to optimize the reactive power distribution of each wind turbine in the wind farm. In a wind farm, due to the wake effect between adjacent wind turbines, each wind turbine has different reactive power capacity in space. Adaptive gain AG i (v i ) can ensure that the downstream wind turbine with larger reactive capacity is set with a larger gain, thereby providing stronger voltage support capability, while the gain of the upstream wind turbine is relatively small to avoid overload or unnecessary wear. When the input wind speed of the wind turbine is greater than or equal to the rated wind speed, the adaptive gain AG i (v i ) sets the droop gain to zero to maintain stable operation of the voltage in the land grid.

[0054] In an exemplary embodiment, before determining the adaptive gain of the wind turbine through the current second reactive capacity of the wind turbine in the offshore wind farm, the method also includes: determining the third reactive power of the wind turbine according to the fixed droop gain of the wind turbine; and determining a positive proportional coefficient of the adaptive gain and the second reactive capacity according to the third reactive power and the second reactive power.

[0055] In an exemplary embodiment, before determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, the method further includes: determining the third reactive power ΔQ according to the following formula: t : Wherein, n is the number of wind turbines, R is the equivalent impedance at the grid connection point of the offshore wind farm, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm; determining the proportional coefficient C of the adaptive gain and the second reactive capacity according to the third reactive power and the second reactive power: Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine, k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm.

[0056] The third reactive power ΔQ t : According to the fixed droop gain of the wind turbine, the second reactive power ΔQ t : According to the adaptive gain of the wind turbine, the two equations are equal to obtain the proportional coefficient C of the adaptive gain and the second reactive capacity: When the wind speed changes and causes the reactive capacity of the wind farm to change, the proportional coefficient C will be adaptively adjusted to ensure that the wind farm can provide an appropriate proportion of reactive power and maintain the voltage stability of the grid connection point.

[0057] In order to better understand the process of the above-mentioned voltage regulation method, the above-mentioned voltage regulation method is described below in combination with an optional embodiment, but it is not used to limit the technical solution of the embodiment of the present application.

[0058] Figure 3 is a topological structure diagram of a target converter of a voltage regulation method according to an embodiment of the present application, such as Figure 3 As shown, specifically including the following:

[0059] The modular multilevel matrix converter (M3C) is characterized by its matrix structure and multi-level voltage output capability. It consists of multiple parallel submodules, each of which is constructed by multiple series-connected level units. Among them, the input side of M3C is connected to the onshore power grid and usually operates at power frequency (50Hz or 60Hz). The input side is connected to the power grid through a filter network composed of a series of inductors and capacitors to absorb power grid fluctuations and suppress harmonics. The output side of M3C is connected to the offshore wind farm and operates at a low frequency (usually lower than the power frequency). The design of the output side needs to take into account the volatility of wind speed inside the wind farm and the characteristics of low-frequency power transmission, and achieve efficient energy exchange with the wind farm through precise control.

[0060] The power frequency side of M3C adopts the inverter voltage control based on the reactive power-voltage droop characteristic, which can adaptively adjust its reactive power output to support the voltage level according to the real-time changes of the grid voltage. In order to further optimize the effect of reactive voltage support, the power frequency side control strategy of M3C converter introduces an adaptive droop coefficient. The adaptive droop coefficient is dynamically adjusted according to the current maximum reactive capacity of the converter to ensure that under different operating conditions, the M3C converter can provide the best voltage support while maintaining its own stable operation.

[0061] Obviously, the embodiments described above are only some embodiments of the present application, not all embodiments. In order to better understand the above voltage regulation method, the above process is described below in conjunction with the embodiments, but it is not intended to limit the technical solutions of the embodiments of the present application, specifically:

[0062] Figure 4 is a system structure diagram of a voltage regulation method according to an embodiment of the present application, such as Figure 4 As shown, specifically including the following:

[0063] When the wind speed captured by the wind turbines in an offshore wind farm changes, the active power and reactive power that each wind turbine can output will also fluctuate. Under high wind speed conditions, the wind turbine may reach its maximum active power output, at which time its reactive power regulation ability will be weakened. At the same time, the voltage demand of the land power grid may also fluctuate due to changes in industrial activities, residential electricity consumption, etc., requiring the offshore wind farm to provide additional reactive power for voltage support.

[0064] When the voltage of the land grid fluctuates, the M3C converter dynamically adjusts its reactive power output according to the active power currently being transmitted. This means that if the active power being transmitted is low, the M3C converter can provide more reactive power to help stabilize the voltage. Conversely, if the active power being transmitted is close to the maximum value, the reactive power output of the M3C converter will be limited to avoid the risk of overload.

[0065] Different wind turbines in an offshore wind farm have different reactive power regulation capabilities according to their locations and captured wind speeds. The adaptive droop gain control strategy will adaptively adjust the droop gain according to the wind speed and maximum reactive capacity of each wind turbine. When the wind speed of the upstream wind turbine (i.e., the wind turbine close to the land grid) is high, resulting in a reduction in reactive capacity, the adaptive droop gain control strategy will make full use of the reactive voltage control capability of the downstream wind turbine (i.e., the wind turbine far away from the land grid, which is less affected by the wake effect and can provide more reactive capacity), and improve the voltage control capability of the entire wind farm by adaptively increasing the droop gain.

[0066] The above embodiment explains the implementation process of the voltage regulation method in a specific scenario. The voltage regulation method is described below in conjunction with an optional embodiment, but is not intended to limit the technical solution of the embodiment of the present application.

[0067] Figure 5 is a schematic diagram of reactive power-voltage droop characteristics of a voltage regulation method according to an embodiment of the present application, such as Figure 5 As shown, specifically including the following:

[0068] In traditional constant voltage control, the converter usually uses a non-differential PI regulator, that is, a proportional integral regulator, to maintain the constant voltage at the grid connection point. However, this control method has limited response speed and effect when dealing with grid voltage fluctuations, and cannot effectively utilize the reactive power regulation capability of the converter. In reactive-voltage droop characteristic control, the reactive power output of the converter is no longer a fixed value, but is dynamically adjusted according to the deviation between the actual voltage and the target voltage at the grid connection point, as well as the current active power transmission status. This control strategy replaces the non-differential proportional regulation part in the PI regulator with a differential proportional regulation, taking into account the deviation between the actual voltage and the target voltage, so that the reactive power output can be controlled more accurately.

[0069] Figure 6 is a reactive power-voltage droop characteristic control block diagram of a voltage regulation method according to an embodiment of the present application, such as Figure 6 As shown, specifically including the following:

[0070] In the control block diagram of reactive power-voltage droop control, the input signal includes the rated value of the grid voltage V s_ref and the actual measured value Vs These two values ​​are fed into a differentiator to calculate the difference between them, V s_ref -V s . Difference V s_ref -V s The size reflects the deviation between the grid voltage and the rated voltage. The difference V s_ref -V s Multiply by the adaptive droop coefficient K Q (P), the first reactive power ΔQ that the target converter needs to output is generated. This calculation process follows the reactive power-voltage droop characteristic, that is, when ΔQ increases, the target converter will increase the reactive power output to support the grid voltage; when ΔQ decreases, the reactive power output will decrease accordingly to avoid excessive grid voltage. The first reactive power ΔQ is also affected by the maximum reactive power capacity Q of the converter. max In the control block diagram, the calculated result of ΔQ is compared with the maximum reactive capacity that the converter can currently provide to determine -Q max ≤ΔQ≤Q max .

[0071] Figure 7 is a second reactive power range diagram of a voltage regulation method according to an embodiment of the present application, such as Figure 7 As shown, specifically including the following:

[0072] The green area in the figure of this embodiment represents the reactive power range that the wind farm can safely and reliably output at different wind speeds. This range is determined based on the physical characteristics of the wind turbine, electrical limitations, and the overall design of the wind farm. In the green area, the wind turbine can operate stably without exceeding the rated capacity of its electrical equipment to avoid overload or damage. The figure shows that as the wind turbine input wind speed increases, the maximum allowable reactive power capacity gradually decreases. This is because when the wind speed increases, the wind turbine can capture more wind energy to generate active power. As the active power increases, the residual power capacity of the wind turbine converter (i.e., the part that can be used for reactive power regulation) will decrease, so the maximum reactive power that can be provided will also decrease. When the input wind speed of the wind turbine reaches or exceeds the rated wind speed, the active power output of the wind turbine reaches the maximum value. At this time, the power capacity of the wind turbine converter is mainly used to ensure the output of active power, and there is almost no residual capacity for reactive power regulation. This means that when the wind speed reaches or exceeds the rated wind speed, the green area (safe and reliable reactive power output range) almost disappears, indicating that the reactive power regulation ability of the wind turbine is very limited when it approaches or reaches the maximum active power output.

[0073] Figure 8 is a block diagram of an adaptive gain control strategy of a voltage regulation method according to an embodiment of the present application, such as Figure 8 As shown, specifically including the following:

[0074] In the control block diagram of the wind turbine adaptive gain control strategy, the input signal includes the measured voltage V at the grid connection point of the offshore wind farm. sys and the rated voltage V at the grid connection point of the offshore wind farm nom Based on the input signal, the control system calculates the adaptive gain AG i (v i ).AG i (v i ) is dynamically adjusted according to the current maximum reactive power capacity of the wind turbine and the actual wind speed, ensuring that under different wind speed conditions, the wind turbine can provide appropriate reactive power output to support the grid voltage. Adaptive Gain AG i (v i ) calculation takes into account the wake effect between adjacent wind turbines and the change in wind speed over time to optimize the reactive power output distribution of the entire wind farm.

[0075] Fig. 9 is a first simulation diagram of a second reactive power of a voltage regulation method according to an embodiment of the present application, such as Fig. 9 As shown, specifically including the following:

[0076] In an offshore wind farm environment, changes in wind speed have a significant impact on the voltage regulation capability of the wind farm. Based on the comparison between the fixed droop gain control strategy (i.e., FGCS in the figure) and the adaptive droop gain control strategy (i.e., AGCS in the figure), the difference in the voltage regulation effect of the two strategies on the grid connection point can be clearly seen in the figure shown in this embodiment, and why the adaptive strategy can more effectively support voltage stability when the wind speed changes.

[0077] After the wind speed changes, the FGCS strategy can maintain the grid connection point voltage at 0.9448pu, which shows that FGCS has a certain voltage regulation capability, keeping the voltage deviation within the range of -10% to 10%, meeting the voltage requirements for normal operation of offshore wind farms. Similarly, after the wind speed changes, AGCS maintains the grid connection point voltage at a higher level of 0.957pu. Compared with FGCS, the steady-state voltage of AGCS is 0.0122pu higher, which shows that AGCS has better voltage regulation capabilities. More importantly, the steady-state voltage of AGCS is 0.068pu higher than that without any control strategy (i.e., no control state), which significantly improves the performance of voltage control, ensures the stable operation of the wind farm, and also improves the operating efficiency of the frequency-divided transmission system.

[0078] Fig.10 is a second simulation diagram of a second reactive power of a voltage regulation method according to an embodiment of the present application, such as Fig.10 As shown, specifically including the following:

[0079] In FGCS, the allocation of reactive power is based on a fixed droop gain, which means that the reactive power output capacity of wind turbines will not be adaptively adjusted when the wind speed changes. When the wind speed increases, the reactive power output of upstream wind turbines (i.e., WT1, WT2, WT3, WT4, WT8, and WT12 in the fourth column and the first row) is severely limited, or even constrained to 0 Mvar, because they are close to or reach the maximum active power output capacity. This is because when the wind speed increases, the wind energy captured by the wind turbine is converted into active power, and the total power capacity of the wind turbine converter is limited, so it is impossible to output the maximum active power and provide additional reactive power at the same time. However, since the upstream wind turbine cannot provide reactive power, this leads to an increase in the voltage deviation at the PCC point, that is, the amplitude of the voltage change exceeds the normal operating range. In order to compensate for this voltage deviation, other wind turbines in the offshore wind farm (WT5 to WT7, WT9 to WT11, WT13 to WT16) need to increase their reactive power output to maintain the voltage stability of the entire wind farm.

[0080] Fig.11 is a third simulation diagram of a second reactive power of a voltage regulation method according to an embodiment of the present application, such as Fig.11 As shown, specifically including the following:

[0081] Under the AGCS mechanism, the droop gain of the wind turbine is not fixed, but is adaptively adjusted according to the current operating conditions (such as wind speed changes, reactive capacity and location information). This means that when the wind speed increases and the upstream wind turbine approaches or reaches its maximum active power output, the AGCS will automatically reduce the droop gain of these wind turbines, reduce their reactive power output, and even constrain them to 0Mvar. This adaptive adjustment process is based on real-time monitoring and evaluation of the reactive capacity of the wind turbine, ensuring that the wind turbine can give priority to the output of active power at high wind speeds, avoiding active power loss due to reactive power output restrictions. At the same time, the AGCS mechanism can intelligently turn to the downstream wind turbines (i.e., other wind turbines except the WT in the fourth column and the first row) for reactive power regulation, appropriately increase the droop gain of these wind turbines, and thus improve their reactive power output capacity. The key to this is that the downstream wind turbines still retain a large reactive power regulation margin in the early stage of wind speed increase, especially when the wake effect is small. AGCS can make full use of this feature, allowing downstream wind turbines to take on more reactive power regulation tasks, compensating for the reduction in reactive power output of upstream wind turbines, and thus maintaining the voltage level stability of the entire wind farm grid connection point (i.e., PCC in the figure).

[0082] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of each embodiment of the present application.

[0083] In this embodiment, a voltage regulating device is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made are not repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0084] Fig.12 is a structural block diagram of a voltage regulating device according to an embodiment of the present application, the device comprising:

[0085] A first determination module 10 is used to determine the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit power between the offshore wind farm and the land power grid;

[0086] A second determination module 12 is used to determine, when the voltage deviates from the rated voltage, an adaptive droop coefficient of the land power grid according to a current first reactive capacity of the target converter, and determine a first reactive power of the land power grid according to the adaptive droop coefficient, and to determine an adaptive gain of the wind turbine according to a current second reactive capacity of the wind turbine in the offshore wind farm, and determine a second reactive power of the wind turbine according to the adaptive gain;

[0087] The regulating module 14 is configured to regulate the voltage of the land power grid according to the first reactive power and the second reactive power.

[0088] Through the above device, the voltage of the land power grid is determined through the target converter, wherein one end of the target converter is connected to the land power grid and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid; when the voltage deviates from the rated voltage, the adaptive droop coefficient of the land power grid is determined according to the current first reactive capacity of the target converter, and the first reactive power of the land power grid is determined according to the adaptive droop coefficient, and the adaptive gain of the wind turbine is determined according to the current second reactive capacity of the wind turbine in the offshore wind farm, and the second reactive power of the wind turbine is determined according to the adaptive gain; the voltage of the land power grid is adjusted according to the first reactive power and the second reactive power. Thus, the problem that the traditional wind farm grid-connected control strategy in the related art adopts preset control parameters and cannot dynamically adjust the grid voltage, resulting in instability of the power system, is solved.

[0089] In an exemplary embodiment, the second determination module 12 is further configured to determine the first reactive capacity Q according to the following formula: max : Among them, S max is the maximum transmission capacity of the target converter, P is the active power currently transmitted by the target converter to the land power grid; the adaptive droop coefficient K of the land power grid is determined according to the following formula: Q (P): Among them, C is the relevant proportional coefficient.

[0090] In an exemplary embodiment, the second determining module 12 is further configured to determine the first reactive power ΔQ according to the following formula: ΔQ=K Q (P)(V s_ref -V s ), where K Q (P) is the adaptive droop coefficient of the land power grid, V s_ref is the reference value of the voltage of the target converter connected to the land grid, V S is the measured value of the voltage of the land grid connected to the target converter, -Q max ≤ΔQ≤Q max , Q max is the first reactive capacity.

[0091] In an exemplary embodiment, the second determination module 12 is further configured to determine the active power P of the wind turbine according to the following formula: t :P t =k opt v i 3 , where k optis the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm; the second reactive capacity Q is determined according to the following formula W : Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine; the adaptive gain AG is determined according to the following formula i (v i ): Wherein, C is a positive proportional coefficient between the adaptive gain and the second reactive capacity, and i is a positive integer.

[0092] In an exemplary embodiment, the second determination module 12 is further configured to determine the second reactive power ΔQ according to the following formula: i :ΔQ i =-AG i (v i )(V sys -V nom ), where i is a positive integer, AG i (v i ) is the adaptive gain, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm.

[0093] In an exemplary embodiment, the second determination module 12 is further used to determine the third reactive power of the wind turbine according to the fixed droop gain of the wind turbine; and determine the proportional coefficient of the adaptive gain and the second reactive capacity according to the third reactive power and the second reactive power.

[0094] In an exemplary embodiment, the second determination module 12 is further configured to determine the third reactive power ΔQ according to the following formula: t : Wherein, n is the number of wind turbines, R is the equivalent impedance at the grid connection point of the offshore wind farm, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm; determining the proportional coefficient C of the adaptive gain and the second reactive capacity according to the third reactive power and the second reactive power: Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine, k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm.

[0095] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.

[0096] Optionally, in this embodiment, the storage medium may be configured to store a computer program for performing the following steps:

[0097] S1, determining the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid, and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid;

[0098] S2, when the voltage deviates from the rated voltage, determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter, and determining the first reactive power of the land power grid according to the adaptive droop coefficient, and determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, and determining the second reactive power of the wind turbine according to the adaptive gain;

[0099] S3: Regulate the voltage of the land power grid according to the first reactive power and the second reactive power.

[0100] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0101] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0102] An embodiment of the present application further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0103] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0104] S1, determining the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid, and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid;

[0105] S2, when the voltage deviates from the rated voltage, determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter, and determining the first reactive power of the land power grid according to the adaptive droop coefficient, and determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, and determining the second reactive power of the wind turbine according to the adaptive gain;

[0106] S3: Regulate the voltage of the land power grid according to the first reactive power and the second reactive power.

[0107] In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0108] An embodiment of the present application further provides a computer program product, comprising a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program product, and when the computer program is executed by a processor, the steps of the method described in each embodiment of the present application are implemented.

[0109] Optionally, in this embodiment, the above computer program may be configured to implement the following steps when executed by a processor:

[0110] S1, determining the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid, and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land power grid;

[0111] S2, when the voltage deviates from the rated voltage, determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter, and determining the first reactive power of the land power grid according to the adaptive droop coefficient, and determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, and determining the second reactive power of the wind turbine according to the adaptive gain;

[0112] S3: Regulate the voltage of the land power grid according to the first reactive power and the second reactive power.

[0113] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0114] Obviously, those skilled in the art should understand that the above modules or steps of the present application can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order from that herein, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0115] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A voltage regulation method, characterized in that: include: Determine the voltage of the land grid through a target converter, wherein one end of the target converter is connected to the land grid and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit electricity between the offshore wind farm and the land grid; In the case where the voltage deviates from the rated voltage, determining an adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter, and determining a first reactive power of the land power grid according to the adaptive droop coefficient, and determining an adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, and determining a second reactive power of the wind turbine according to the adaptive gain; The voltage of the land power grid is adjusted according to the first reactive power and the second reactive power.

2. The voltage regulation method according to claim 1, characterized in that: Determining the adaptive droop coefficient of the land power grid according to the current first reactive capacity of the target converter includes: The first reactive capacity Q is determined according to the following formula max : Among them, S max is the maximum transmission capacity of the target converter, and P is the active power currently transmitted by the target converter to the land power grid; The adaptive droop coefficient K of the land power grid is determined according to the following formula: Q (P): Among them, C is the relevant proportional coefficient.

3. The voltage regulation method according to claim 1, characterized in that: Determining a first reactive power of the land power grid according to the adaptive droop coefficient comprises: The first reactive power ΔQ is determined according to the following formula: ΔQ=K Q (P)(V s_ref -V s ), where K Q (P) is the adaptive droop coefficient of the land power grid, V s_ref is the reference value of the voltage of the target converter connected to the land grid, V S a measured value of the voltage of the land grid to which the target converter is connected, -Q max ≤ΔQ≤Q max , Q max is the first reactive capacity.

4. The voltage regulation method according to claim 1, characterized in that: Determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm comprises: The active power P of the wind turbine is determined according to the following formula: t :P t =k opt v i 3 , where k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm; The second reactive capacity Q is determined according to the following formula W : Among them, S W is the rated capacity of a wind turbine converter, the wind turbine converter being used to convert the electrical energy of the wind turbine; The adaptive gain AG is determined according to the following formula i (v i ): Wherein, C is a positive proportional coefficient between the adaptive gain and the second reactive capacity, and i is a positive integer.

5. The voltage regulation method according to claim 1, characterized in that: Determining the second reactive power of the wind turbine according to the adaptive gain includes: The second reactive power ΔQ is determined according to the following formula i :ΔQ i =-AG i (v i )(V sys -V nom ), where i is a positive integer, AG i (v i ) is the adaptive gain, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm.

6. The voltage regulation method according to claim 1, characterized in that: Before determining the adaptive gain of the wind turbine by the current second reactive capacity of the wind turbine in the offshore wind farm, the method further comprises: determining a third reactive power of the wind turbine according to the fixed droop gain of the wind turbine; A proportional coefficient between the adaptive gain and the second reactive capacity is determined according to the third reactive power and the second reactive power.

7. The voltage regulation method according to claim 6, characterized in that: Before determining the adaptive gain of the wind turbine according to the current second reactive capacity of the wind turbine in the offshore wind farm, the method further includes: determining the third reactive power ΔQ according to the following formula t : Wherein, n is the number of wind turbines, R is the equivalent impedance at the grid connection point of the offshore wind farm, V nom is the rated voltage at the grid connection point of the offshore wind farm, V sys is the measured voltage at the grid connection point of the offshore wind farm; The proportional coefficient C of the adaptive gain and the second reactive capacity is determined according to the third reactive power and the second reactive power: Among them, S W is the rated capacity of the wind turbine converter, which is used to convert the electric energy of the wind turbine, k opt is the equivalent coefficient of the wind turbine to obtain the maximum wind energy, v i is the wind speed of the offshore wind farm.

8. A voltage regulating device, characterized in that: include: A first determination module is used to determine the voltage of the land power grid through a target converter, wherein one end of the target converter is connected to the land power grid, and the other end is connected to the offshore wind farm, and the target converter is used to convert and transmit power between the offshore wind farm and the land power grid; a second determination module, configured to determine, when the voltage deviates from the rated voltage, an adaptive droop coefficient of the land power grid according to a current first reactive capacity of the target converter, and determine a first reactive power of the land power grid according to the adaptive droop coefficient, and determine an adaptive gain of the wind turbine according to a current second reactive capacity of the wind turbine in the offshore wind farm, and determine a second reactive power of the wind turbine according to the adaptive gain; A regulating module is used to regulate the voltage of the land power grid according to the first reactive power and the second reactive power.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method according to any one of claims 1 to 7 when executed.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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