Wind power and thermal power generating unit combined frequency modulation method and system based on rotating speed load shedding

Abstract

The invention discloses a wind power and thermal power generating unit combined frequency modulation method and system based on rotating speed load shedding, and the method comprises the steps: calculating a fixed pitch angle and the maximum absorption power of a fan at different wind speeds, and obtaining a maximum power tracking curve below the upper limit of the rotating speed of a rotor; calculating load shedding power at different wind speeds under a set load shedding rate d% based on the maximum power tracking curve below the upper limit of the rotating speed of the rotor to obtain a load shedding power curve below the upper limit of the rotating speed of the rotor; calculating the power absorbed by the fan when the rotating speed of the rotor is at the upper limit according to the load shedding power curve below the upper limit of the rotating speed of the rotor, and fitting to obtain a suboptimal power tracking curve; setting suboptimal power tracking based on the suboptimal power tracking curve, realizing suboptimal power output, and completing load shedding; taking the rotating speed deviation of the thermal power generating unit as the controlled quantity of rotating speed frequency modulation; wind power primary frequency modulation is not excited when the rotating speed deviation of the thermal power generating unit is within a set range; the droop control cooperates with the thermal power generating unit to jointly participate in primary frequency modulation to realize combined frequency modulation.

Description

Background Art

[0002] Faced with the severe challenges of global climate change and environmental problems, energy transformation has become a common goal pursued by governments and the international community. In response to the initiative of the "dual carbon" goal, China is accelerating the construction of a new power system with new energy and power electronic equipment as the core. The rapid development of new energy is gradually becoming the dominant energy source for the construction of China's new power system through power electronic converters. This change has shaped the "double high" characteristics of the power grid, namely a high proportion of new energy access and a high proportion of power electronic equipment applications.

[0003] In traditional power systems, synchronous generators still play a key role. Synchronous generators have the function of establishing grid voltage and frequency, and their large rotor mass can provide inertial support for the grid. In contrast, new energy generator sets are connected to the grid through power electronic equipment. New energy power generation is often intermittent, random, and volatile, and these power electronic equipment cannot provide natural inertia, which reduces the inertia of the grid and the strength of the system, showing the characteristics of a weak grid or even an extremely weak grid. System inertia is one of the important factors in maintaining frequency stability. The decrease in inertia increases the frequency fluctuation amplitude and weakens the ability of the system to return to a stable state when facing various disturbances. After the system inertia is reduced, the frequency stability is challenged by the combined effects of external disturbances and internal power fluctuations.

[0004] Take the Santanghu power grid wind farm in Hami, Xinjiang, for example. The wind farm experienced multiple oscillations in July 2015. In September of the same year, a serious bipolar lockout accident also occurred in the Jinsu UHV DC system in East China. The accident caused an overvoltage fault in the sending-end power grid, and due to insufficient inertia of the power system, the power grid frequency dropped sharply, reaching a serious frequency drop of 0.41Hz.

[0005] The current primary frequency regulation method based on the speed governor of a thermal power unit involves the regulation of a mechanical system. When the system frequency changes, the speed governor of the thermal power unit quickly senses and acts to adjust the unit output power by changing the steam intake of the turbine. Thermal power units usually have a large capacity. Once the regulation action is completed, they can provide a relatively stable and considerable power support for the system, which plays a key role in maintaining the stability of the system frequency.

[0006] The means of primary frequency regulation of wind power include speed frequency regulation, pitch angle frequency regulation and energy storage auxiliary frequency regulation. When primary frequency regulation is performed based on speed regulation, due to the fast response characteristics of power electronic devices, its response speed to frequency changes is faster than that of mechanical speed regulators.

[0007] However, these two frequency regulation mechanisms also have shortcomings. The primary frequency regulation of thermal power units is based on the regulation mechanism of the mechanical system. This process involves the movement of a large number of physical components and complex energy conversion processes, such as the expansion of steam in the turbine, the conversion of mechanical energy and electrical energy, etc. This makes the regulation have obvious inertia, making it difficult for its response speed to quickly keep up with the rapid changes in the system frequency.

[0008] There is a dead zone limit in the primary frequency regulation of wind power. When the system frequency changes slightly, it is difficult for the wind turbine to start the frequency regulation action and the frequency regulation function cannot be effectively exerted. At the same time, wind speed has a significant impact on the frequency regulation capability of wind power. For example, when the wind speed is low, the output power of the wind turbine is limited, and the spare power available for frequency regulation is insufficient; when the wind speed is too high, in order to protect the safety of the unit, the wind turbine may limit the power output or shut down, and its frequency regulation capability will also be greatly reduced. In actual power grid operation, the complex and changeable wind speed conditions make the wind power frequency regulation effect unstable, and it is difficult to continuously provide reliable frequency support for the system. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a method and system for joint frequency regulation of wind power and thermal power units based on speed reduction in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problem caused by the drastic frequency fluctuation of the power system due to the decrease of system inertia.

[0010] The present invention adopts the following technical solutions: A method for joint frequency regulation of wind power and thermal power generation units based on speed reduction, characterized in that it comprises the following steps: Calculate the maximum absorbed power of the wind turbine at fixed pitch angle and different wind speeds, and obtain the maximum power tracking curve below the upper limit of the rotor speed; Based on the maximum power tracking curve below the upper limit of the rotor speed, the load reduction power at different wind speeds under the set load reduction rate d% is calculated to obtain the load reduction power curve below the upper limit of the rotor speed; The power absorbed by the fan when the rotor speed is at the upper limit is calculated according to the load reduction power curve below the upper limit of the rotor speed, and the suboptimal power tracking curve is obtained by fitting; Suboptimal power tracking is set based on the suboptimal power tracking curve to achieve suboptimal power output and complete load reduction; The speed deviation of the thermal power unit is used as the controlled variable of speed frequency regulation; the speed deviation of the thermal power unit is within the set range and does not trigger the primary frequency regulation of wind power; Through droop control, the thermal power units are coordinated to jointly participate in primary frequency regulation to achieve joint frequency regulation.

[0011] Preferably, the maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds is: P = f(ω r ,Vw,θ) in, ω r represents the rotor speed, V w is the wind speed, θ is the pitch angle.

[0012] Preferably, the load shedding power curve ω is obtained by using the quadratic function fitting method. r -Del_ P ( ω r ) as the inverse function of the suboptimal power tracking curve Del_ P - ω r ( P ).

[0013] Preferably, a synchronous generator is used as another type of power source, and the speed deviation of the synchronous generator is used as the system frequency deviation, and the speed deviation of the thermal power unit is used as the system frequency deviation. dω Set as the controlled variable of speed frequency regulation.

[0014] Preferably, the speed deviation of the thermal power unit dω A low-pass filter and a dead zone are set. When the speed deviation dω is within the corresponding range, the primary frequency modulation of wind power is not triggered.

[0015] Preferably, when it is detected that the output active power of the doubly-fed wind turbine generator is less than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed command value is set to be equal to ω r_ref =Del_ P - ω r ( P out ), provides reference speed for the speed controller, and outputs reference torque through the PI controller T ref ; When the active power output by the doubly-fed wind turbine generator is greater than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed command value is set to ω r_ref =Max ω r , provides reference speed for the speed controller, and outputs reference torque through the PI controller T ref .

[0016] Preferably, the droop control is specifically as follows: a negative droop control system is set, and the electromagnetic torque command value of the doubly-fed wind turbine generator is added after multiplying the speed deviation; when a frequency disturbance occurs, the reference torque T ref and additional reference torque ΔTadd Together they form the total reference torque signal T cmd , sent into the rotor control model, passes through the converter current inner loop, and finally changes the output electromagnetic torque and active power, thereby realizing primary frequency modulation of speed control.

[0017] In a second aspect, an embodiment of the present invention provides a wind power and thermal power generation unit joint frequency regulation system based on speed reduction, comprising: The load reduction module calculates the maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds, and obtains the maximum power tracking curve below the upper limit of the rotor speed; based on the maximum power tracking curve below the upper limit of the rotor speed, the load reduction power at different wind speeds under the set load reduction rate d% is calculated, and the load reduction power curve below the upper limit of the rotor speed is obtained; based on the load reduction power curve below the upper limit of the rotor speed, the power absorbed by the wind turbine when the rotor speed is at the upper limit is calculated, and the suboptimal power tracking curve is obtained by fitting; based on the suboptimal power tracking curve, suboptimal power tracking is set to achieve suboptimal power output and complete load reduction; The frequency regulation module uses the speed deviation of the thermal power unit as the controlled variable of the speed frequency regulation; the speed deviation of the thermal power unit is within the set range so as not to trigger the primary frequency regulation of wind power; through droop control, the thermal power units are coordinated to participate in the primary frequency regulation to achieve joint frequency regulation.

[0018] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the above-mentioned method for joint frequency regulation of wind power and thermal power units based on speed reduction are implemented.

[0019] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for joint frequency regulation of wind power and thermal power units based on speed reduction.

[0020] In a fifth aspect, a chip comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the above-mentioned method for joint frequency regulation of wind power and thermal power units based on speed reduction are implemented.

[0021] In a sixth aspect, an embodiment of the present invention provides an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned method for joint frequency regulation of wind power and thermal power units based on speed reduction.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: A method for joint frequency regulation of wind power and thermal power units based on speed reduction. In terms of wind turbine load reduction, when the wind speed is low, only speed reduction can meet the requirement of d% load reduction rate. As the wind speed increases, only speed reduction cannot meet the requirement of d% load reduction rate, and the frequency regulation effect becomes poor. Therefore, joint frequency regulation of thermal power units is required. In terms of frequency regulation, speed regulation is adopted in low wind speed areas to ensure rapid response of primary frequency regulation. As the wind speed increases, wind turbine speed regulation and thermal power unit speed regulator are adopted for joint frequency regulation, which can reduce the harm of overspeed standby to the mechanical structure of the unit when the wind speed is too high and leave sufficient frequency regulation time for the thermal power unit frequency regulation. When the wind speed exceeds the minimum wind speed in the constant power mode, only the thermal power unit frequency regulation is adopted, which avoids the harm of overspeed standby to the mechanical structure of the unit when the wind speed is too high. The present invention effectively makes up for the shortcoming that the speed regulation is applicable to a narrow wind speed power range.

[0023] Furthermore, the inverse function of the obtained load reduction power curve ωr-Del_P(ωr) is used as the suboptimal power tracking curve Del_P-ωr(P). The reference value of the wind turbine speed is given by this curve, which can ensure that when the wind speed is constant, the power absorbed by the wind turbine can gradually approach the suboptimal power under the wind speed.

[0024] Furthermore, when an infinite power source (ideal voltage source) is used, the system frequency response cannot be tested, so a synchronous generator is used as another type of power source. At this time, the synchronous machine speed deviation can be taken as the system frequency offset.

[0025] Furthermore, the primary frequency regulation dead zone refers to the insensitivity zone of the primary frequency regulation unit to the speed when it is near the rated speed. In real scenarios, the grid frequency is always fluctuating. In order to prevent the unit from responding to the primary frequency regulation too frequently, the frequency regulation dead zone is set. When the speed deviation dω is within the corresponding range, the wind power primary frequency regulation is not triggered.

[0026] Furthermore, when the active power output by the doubly-fed wind turbine generator is less than the power absorbed by the wind turbine when the rotor speed is at the upper limit, the rotor speed command value is set to be equal to ω r_ref =Del_ P - ω r ( P out ), at this time, it can be ensured that the wind turbine can rely on speed regulation to maintain a constant power reduction rate; when the output active power of the doubly fed wind turbine generator is less than the power absorbed by the wind turbine when the rotor speed is at the upper limit, the rotor speed command value is set to be equal to ω r_ref =Max ω r At this time, speed regulation alone cannot maintain a constant power load reduction rate. Setting the speed reference value to the maximum can ensure the stable operation of the doubly fed wind turbine and keep the load reduction rate at the maximum value within the allowable range.

[0027] Furthermore, droop control is a control method implemented on the inverter by simulating the droop external characteristics of synchronous generators in traditional power systems. When the active power output of the inverter changes, the frequency of the inverter output voltage changes linearly according to the droop characteristic curve. Through droop control, the electromagnetic torque can be dynamically adjusted according to the speed deviation, so that the fan can respond quickly when the system frequency fluctuates, and cooperate with the thermal power unit to participate in the primary frequency modulation to maintain the stability of the system frequency.

[0028] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0029] In summary, the present invention can give full play to the rapid response characteristics of wind power primary frequency regulation in a system including a doubly-fed wind turbine generator and a thermal power unit under different wind speed conditions, and jointly regulate the frequency with the thermal power unit to ensure the stability of the system frequency.

[0030] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a flow chart of the combined primary frequency regulation of wind power and thermal power in the present invention; Figure 2 It is a combined primary frequency regulation system for thermal power units and fans; Figure 3 It is a primary frequency regulation system involving only three thermal power units; Figure 4 It is a comparison of the frequency regulation effects of thermal power units only and wind-fire combined; Figure 5 A schematic diagram of a computer device provided by an embodiment of the present invention; Figure 6 The present invention is a block diagram of an electronic device provided according to an embodiment. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0035] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0036] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0037] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0038] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0039] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0040] Wind turbines use speed frequency modulation to quickly adjust output power according to the frequency deviation of the system. In current research, the energy for increasing active power when wind turbines perform frequency disturbance support mainly includes rotor kinetic energy release, overspeed standby and pitch angle standby. Traditional active control strategies based on these forms have problems such as small available reserve active power, low economic efficiency and poor implementation effect.

[0041] The release of rotor kinetic energy only utilizes the inertial power brought by the speed change of the wind turbine itself to provide power support in a short period of time during frequency disturbance. It is suitable for improving the short-term frequency support characteristics of wind power, but it is difficult to improve the steady-state long-term frequency characteristics. The speed reserve can effectively increase the lowest frequency point and provide more power support for grid frequency regulation. However, this overspeed reserve control scheme is only applicable to medium and low wind speeds. If the wind speed is large, the overspeed reserve will cause great harm to the mechanical structure of the unit. Therefore, this control method has great limitations. In order to make the wind turbine have a certain power reserve at high wind speed, the speed reserve is used in the low wind speed zone, and the speed is controlled not at the maximum power capture point, leaving power reserve. Due to the fast response characteristics of power electronic devices, its response speed to frequency changes is faster than that of mechanical speed regulators, but the applicable wind speed range is too narrow.

[0042] See also Figure 1 The present invention provides a method for combined frequency regulation of wind power and thermal power generation units based on speed reduction, comprising the following steps: S1, suboptimal power load shedding The primary frequency regulation control based on speed reserve reduces the wind energy capture coefficient through overspeed control, so that the wind turbine operates at a suboptimal power tracking point, thereby obtaining a certain active power reserve. This suboptimal operation mode is usually called load reduction operation of the wind turbine.

[0043] S101. Determine the maximum power tracking curve Suboptimal power load reduction strategy based on the wind turbine absorbed power formula P = f(ω r ,Vw,θ) , at a fixed pitch angle ( θ =0). ω r represents the rotor speed,V w is the wind speed, θ is the pitch angle. Through this calculation, the absorbed power of the wind turbine under different working conditions can be obtained, and then the maximum power point tracking (MPPT) curve below the upper limit of the rotor speed can be obtained. ω r -MAX_ P , providing basic data for subsequent power analysis.

[0044] S102. Determine load reduction power curve According to the maximum power point tracking (MPPT) curve ω r -MAX_ P , for a certain load reduction rate ( d% ) and below the upper limit of the rotor speed, calculate the corresponding load reduction power Del_P , thus obtaining the load reduction power curve ω r -Del_ P(ω r ) ; This step helps to determine the power adjustment range of the wind turbine under different wind speeds and load reduction requirements, and is a key link in achieving suboptimal power load reduction.

[0045] S103: Determine a suboptimal power tracking curve Based on load shedding power curve ω r -MAX_ P Calculate the power absorbed by the fan when the rotor speed is at the upper limit. P _Max ω r Then, the load shedding power curve ω is obtained by using the quadratic function fitting method. r -Del_ P ( ω r ), that is, the suboptimal power tracking curve Del_ P - ω r ( P ). The determination of this curve provides a basis for subsequent control command adjustment according to the actual output power of the wind turbine.

[0046] S104: Determine the rotor speed command value Implement suboptimal power tracking strategy to detect the output active power of doubly-fed wind turbine in real time P out .when P out Less than Del_P _Max ω r When the rotor speed command value is ω r_ref =Del_ P - ω r ( P out );when P out >Del_ P _Max ω r season ω r_ref =Max ω r This control logic is designed to reasonably adjust the rotor speed according to the wind turbine output power to achieve suboptimal power output and improve the frequency regulation performance of the wind-fire combined system.

[0047] S2, wind and fire combined primary frequency modulation S201, set the controlled quantity of speed frequency modulation Since the system frequency response cannot be tested when an infinite bus (voltage source) is used, a synchronous generator is used as another type of power source. At this time, the speed deviation of the synchronous generator can be taken as the system frequency deviation. Therefore, the speed deviation of the thermal power unit dω Set as the controlled variable of speed frequency modulation.

[0048] S202, primary frequency modulation dead zone setting Speed ​​deviation of thermal power unit dω Set a low-pass filter and dead zone. Within a certain range, when the speed deviation dω is within this range, the wind power primary frequency regulation will not be triggered. This will prevent the system from overreacting to small speed deviations, reduce unnecessary frequency regulation actions, and improve the stability and reliability of system operation.

[0049] S203, fan frequency control strategy Set the droop control coefficient to a negative value Kω r , the speed deviation dω Multiply Kω r Then add to the electromagnetic torque command value of the doubly fed wind turbine T e_ref Through droop control, the electromagnetic torque can be dynamically adjusted according to the speed deviation, so that the fan can respond quickly when the system frequency fluctuates, and cooperate with the thermal power unit to participate in the primary frequency regulation to maintain the stability of the system frequency.

[0050] It will be appreciated by those skilled in the art that various aspects of the present invention may be implemented as a system, method or program product. Therefore, various aspects of the present invention may be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software, which may be collectively referred to herein as a "circuit", "module" or "platform".

[0051] In another embodiment of the present invention, a wind power and thermal power group joint frequency regulation system based on speed load shedding is provided. The system can be used to implement the above-mentioned wind power and thermal power group joint frequency regulation method based on speed load shedding. Specifically, the wind power and thermal power group joint frequency regulation system based on speed load shedding includes a load shedding module and a frequency regulation module.

[0052] Among them, the load reduction module calculates the maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds, and obtains the maximum power tracking curve below the upper limit of the rotor speed; based on the maximum power tracking curve below the upper limit of the rotor speed, the load reduction power at different wind speeds under the set load reduction rate d% is calculated, and the load reduction power curve below the upper limit of the rotor speed is obtained; according to the load reduction power curve below the upper limit of the rotor speed, the power absorbed by the wind turbine when the rotor speed is at the upper limit is calculated, and the suboptimal power tracking curve is obtained by fitting; based on the suboptimal power tracking curve, suboptimal power tracking is set to achieve suboptimal power output and complete load reduction; The frequency regulation module uses the speed deviation of the thermal power unit as the controlled variable of the speed frequency regulation; the speed deviation of the thermal power unit is within the set range so as not to trigger the primary frequency regulation of wind power; through droop control, the thermal power units are coordinated to participate in the primary frequency regulation to achieve joint frequency regulation.

[0053] In another embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, graphics processors (GPU), tensor processors (TPU), digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the wind power and thermal power unit joint frequency modulation method based on speed reduction, including: Calculate the maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds, and obtain the maximum power tracking curve below the upper limit of the rotor speed; calculate the load reduction power at different wind speeds under the set load reduction rate d% based on the maximum power tracking curve below the upper limit of the rotor speed, and obtain the load reduction power curve below the upper limit of the rotor speed; calculate the power absorbed by the wind turbine when the rotor speed is at the upper limit according to the load reduction power curve below the upper limit of the rotor speed, and fit the suboptimal power tracking curve; set the suboptimal power tracking based on the suboptimal power tracking curve to achieve suboptimal power output and complete load reduction; use the speed deviation of the thermal power unit as the controlled variable of the speed frequency regulation; make sure that the speed deviation of the thermal power unit does not trigger the primary frequency regulation of wind power within the set range; coordinate the thermal power units to participate in the primary frequency regulation through droop control to achieve joint frequency regulation.

[0054] See also Figure 5 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the wind power and thermal power unit joint frequency regulation method based on speed reduction in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the wind power and thermal power unit joint frequency regulation system based on speed reduction in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0055] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 5 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0056] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, graphics processing units (GPU), tensor processing units (TPU), digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0057] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0058] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0059] See also Figure 6The terminal device 600 is an electronic device, and the electronic device is in the form of a general computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0060] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0061] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0062] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0063] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0064] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0065] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs. It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-VolatileMemory), such as at least one disk memory.

[0066] The processor may load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for combined frequency regulation of wind power and thermal power generation units based on speed reduction in the above embodiment; the processor may load and execute the following steps: Calculate the maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds, and obtain the maximum power tracking curve below the upper limit of the rotor speed; calculate the load reduction power at different wind speeds under the set load reduction rate d% based on the maximum power tracking curve below the upper limit of the rotor speed, and obtain the load reduction power curve below the upper limit of the rotor speed; calculate the power absorbed by the wind turbine when the rotor speed is at the upper limit according to the load reduction power curve below the upper limit of the rotor speed, and fit the suboptimal power tracking curve; set the suboptimal power tracking based on the suboptimal power tracking curve to achieve suboptimal power output and complete load reduction; use the speed deviation of the thermal power unit as the controlled variable of the speed frequency regulation; make sure that the speed deviation of the thermal power unit does not trigger the primary frequency regulation of wind power within the set range; coordinate the thermal power units to participate in the primary frequency regulation through droop control to achieve joint frequency regulation.

[0067] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0068] Simulation scenario The system used in the present invention consists of two synchronous generators (including excitation and speed regulator), a wind farm unit and a load of 1503MW. The two thermal power units are both 900MW in capacity. The wind farm unit simulates the equivalent situation of 100 1.5MW double-fed wind turbines. The load is 125MW at 40s and 100MW at 80s. Figure 2 shown.

[0069] The system used for comparison consists of a thermal power unit with three synchronous generators. Turbine Unit 1 and Turbine Unit 2 are both 900MW in capacity, and Turbine Unit 3 is 1500MW. The load is 125MW at 40s and 100MW at 80s. Figure 3 shown.

[0070] Simulation Results Combination Figure 4 The simulation results show that the combined primary frequency regulation of thermal power units and doubly-fed wind turbines based on speed reduction has significantly reduced the frequency oscillation peak value caused by either adding or removing the load, compared with the primary frequency regulation of thermal power units alone. The frequency stability value after reaching steady state is not much different, which is beneficial to ensure the frequency stability of the system.

[0071] In summary, the invention provides a method and system for joint frequency regulation of wind power and thermal power units based on speed reduction, which can make wind power and thermal power generators jointly regulate their respective output active power in response to load changes in a system containing double-fed wind power generation and thermal power units. Compared with the frequency regulation of thermal power generators alone, the joint frequency regulation of the invention can significantly reduce the amplitude of the system frequency jump / drop, ensuring that the system base frequency change is maintained within a reasonable range.

[0072] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0073] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0074] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0075] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0076] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0077] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0078] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0079] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0080] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0082] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for joint frequency regulation of wind power and thermal power generation units based on speed reduction, characterized in that: The following steps are involved: Calculate the maximum absorbed power of the wind turbine at fixed pitch angle and different wind speeds, and obtain the maximum power tracking curve below the upper limit of the rotor speed; Based on the maximum power tracking curve below the upper limit of the rotor speed, the load reduction power at different wind speeds under the set load reduction rate d% is calculated to obtain the load reduction power curve below the upper limit of the rotor speed; The power absorbed by the fan when the rotor speed is at the upper limit is calculated according to the load reduction power curve below the upper limit of the rotor speed, and the suboptimal power tracking curve is obtained by fitting; Set suboptimal power tracking based on the suboptimal power tracking curve to achieve suboptimal power output and complete load reduction; The speed deviation of the thermal power unit is used as the controlled variable of speed frequency regulation; the speed deviation of the thermal power unit is within the set range and does not trigger the primary frequency regulation of wind power; Through droop control, the thermal power units are coordinated to jointly participate in primary frequency regulation to achieve joint frequency regulation.

2. The method for combined frequency regulation of wind power and thermal power generation units based on speed reduction according to claim 1 is characterized in that: The maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds is: P = f(ω r ,Vw,θ) in, ω r represents the rotor speed, V w is the wind speed, θ is the pitch angle.

3. The method for combined frequency regulation of wind power and thermal power generation units based on speed reduction according to claim 1 is characterized in that: The load shedding power curve ω is obtained by using the quadratic function fitting method r -Del_ P ( ω r ) is taken as the inverse function of the suboptimal power tracking curve Del_ P - ω r ( P ).

4. The method for combined frequency regulation of wind power and thermal power generation units based on speed reduction according to claim 1 is characterized in that: Synchronous generators are used as another type of power source, and the speed deviation of the synchronous generator is used as the system frequency deviation. dω Set as the controlled variable of speed frequency modulation.

5. The method for combined frequency regulation of wind power and thermal power generation units based on speed reduction according to claim 1 is characterized in that: Speed ​​deviation of thermal power unit dω A low-pass filter and a dead zone are set. When the speed deviation dω is within the corresponding range, the primary frequency modulation of wind power is not triggered.

6. The method for combined frequency regulation of wind power and thermal power generation units based on speed reduction according to claim 1 is characterized in that: When the output active power of the double-fed wind turbine generator is detected to be less than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed command value is set to be equal to ω r_ref =Del_ P - ω r ( P out ), provides reference speed for the speed controller, and outputs reference torque through the PI controller T ref ; When the active power output by the doubly-fed wind turbine generator is greater than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed command value is set to ω r_ref =Max ω r , provides reference speed for the speed controller, and outputs reference torque through the PI controller T ref .

7. The method for combined frequency regulation of wind power and thermal power generation units based on speed reduction according to claim 1 is characterized in that: The specific droop control is as follows: set a negative droop control system, multiply the speed deviation and add the electromagnetic torque command value of the doubly fed wind turbine generator; when the frequency disturbance occurs, the reference torque T ref and additional reference torque ΔT add Together they form the total reference torque signal T cmd , sent into the rotor control model, passes through the converter current inner loop, and finally changes the output electromagnetic torque and active power, thereby realizing primary frequency modulation of speed control.

8. A wind power and thermal power generation unit joint frequency regulation system based on speed reduction, characterized in that: include: The load reduction module calculates the maximum absorbed power of the wind turbine at a fixed pitch angle and different wind speeds, and obtains the maximum power tracking curve below the upper limit of the rotor speed; Based on the maximum power tracking curve below the upper limit of the rotor speed, the load reduction power at different wind speeds under the set load reduction rate d% is calculated to obtain the load reduction power curve below the upper limit of the rotor speed; The power absorbed by the fan when the rotor speed is at the upper limit is calculated according to the load reduction power curve below the upper limit of the rotor speed, and a suboptimal power tracking curve is obtained by fitting; suboptimal power tracking is set based on the suboptimal power tracking curve to achieve suboptimal power output and complete load reduction; The frequency regulation module uses the speed deviation of the thermal power unit as the controlled variable of the speed frequency regulation; the speed deviation of the thermal power unit is within the set range so as not to trigger the primary frequency regulation of wind power; through droop control, the thermal power units are coordinated to participate in the primary frequency regulation to achieve joint frequency regulation.

9. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform the method of any one of claims 1 to 7.

10. A computing device, characterized in that include: One or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include steps for executing the method according to any one of claims 1 to 7.

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