A wind power and thermal power unit combined frequency modulation method and system based on speed reduction load

Abstract

The application discloses a wind power and thermal power unit combined frequency modulation method and system based on rotating speed load shedding, calculates the maximum power absorption of a wind turbine under different wind speeds and a fixed pitch angle, obtains a maximum power tracking curve below the upper limit of the rotating speed, calculates the load shedding power under different wind speeds based on the maximum power tracking curve below the upper limit of the rotating speed, obtains a load shedding power curve below the upper limit of the rotating speed, calculates the power absorbed by the wind turbine when the rotating speed is at the upper limit according to the load shedding power curve below the upper limit of the rotating speed, and fits to obtain a suboptimal power tracking curve, sets the suboptimal power tracking based on the suboptimal power tracking curve, realizes suboptimal power output, completes load shedding, takes the rotating speed deviation of the thermal power unit as a controlled variable of the rotating speed frequency modulation, does not excite the primary frequency modulation of the wind power within the set range of the rotating speed deviation of the thermal power unit, cooperates with the thermal power unit to participate in the primary frequency modulation through droop control, and realizes combined frequency modulation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of primary frequency modulation of new energy power systems, and particularly relates to a wind power and thermal power unit combined frequency modulation method and system based on speed reduction. BACKGROUND

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

[0003] In the traditional power system, 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 inertia support for the grid. In contrast, new energy generators are connected to the grid through power electronic devices, and new energy generation often has intermittency, randomness and volatility, and these power electronic devices cannot provide natural inertia, resulting in reduced grid inertia and reduced system strength, presenting weak grid or even extremely weak grid characteristics. System inertia is one of the important factors for maintaining frequency stability, and the decrease in inertia makes the system's ability to recover to a stable state weaker when facing various disturbances. Under the combined action of external disturbances and internal power fluctuations, the frequency stability is challenged.

[0004] Taking the Santanghu wind farm in Hami, Xinjiang as an example, the wind farm experienced multiple oscillation phenomena in July 2015. In September of the same year, a serious bipolar blocking accident occurred in the Jin-Su ultra-high voltage direct current system in the East China region. This accident caused overvoltage failure in the sending end power grid, and then due to the lack of inertia of the power system, the grid frequency dropped sharply to 0.41 Hz, a serious frequency drop.

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

[0006] The means of primary frequency regulation of wind power includes speed regulation, pitch angle regulation and energy storage auxiliary regulation. When the primary frequency regulation is based on speed regulation, the response speed of the power electronic device is faster than that of the mechanical governor due to the fast response characteristics of the power electronic device.

[0007] However, these two frequency regulation mechanisms have some disadvantages. The primary frequency regulation of thermal power units is based on the regulation mechanism of mechanical systems. 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, which makes it difficult to quickly follow the sharp changes in system frequency.

[0008] The speed primary frequency regulation of wind power has a dead zone limit. 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 played. At the same time, the 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 standby power for frequency regulation is insufficient. When the wind speed is too high, the wind turbine may limit the power output or shut down to protect the unit safety, and at this time, the frequency regulation capability of the wind turbine will also be greatly reduced. In actual power grid operation, the complex and variable wind speed conditions make the frequency regulation effect of wind power unstable, and it is difficult to provide reliable frequency support for the system. SUMMARY

[0009] The technical problem to be solved by the present application is to provide a wind power and thermal power unit combined frequency regulation method and system based on speed reduction load to solve the technical problem caused by the sharp frequency fluctuation of the power system due to the decrease in system inertia.

[0010] The application adopts the following technical solutions:

[0011] A wind power and thermal power unit combined frequency regulation method based on speed reduction load, characterized in that it comprises the following steps:

[0012] Calculate the maximum power absorption of the wind turbine under different wind speeds and the maximum power tracking curve below the upper limit of the rotor speed;

[0013] Calculate the load reduction power under different wind speeds 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;

[0014] 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 to obtain a suboptimal power tracking curve;

[0015] Set a suboptimal power tracking based on the suboptimal power tracking curve, realize suboptimal power output, and complete load reduction;

[0016] The speed deviation of the thermal power unit is taken as the controlled variable of the speed frequency modulation, and the speed deviation of the thermal power unit is not triggered within the set range.

[0017] The droop control cooperates with the thermal power unit to participate in the primary frequency modulation, and realizes the joint frequency modulation.

[0018] Preferably, the fixed pitch angle and the maximum absorption power of the fan under different wind speeds are:

[0019] P = f(ω r , Vw, θ)

[0020] wherein, ω r represents the rotor speed, V w is the wind speed, θ is the pitch angle.

[0021] Preferably, the inverse function of the reduced load power curve ω r -Del_ P ( ω r ) obtained by the quadratic function fitting method is taken as the suboptimal power tracking curve Del_ P - ω r ( P ).

[0022] Preferably, the synchronous generator is taken as another type of power supply, the speed deviation of the synchronous machine is taken as the system frequency deviation, and the speed deviation of the thermal power unit ω is set as the controlled variable of the speed frequency modulation.

[0023] Preferably, a low-pass filter and a dead zone are set for the speed deviation of the thermal power unit dω , and the primary frequency modulation of the wind power is not triggered when the speed deviation dω is within the corresponding range.

[0024] Preferably, when the output active power of the doubly-fed wind power generator is less than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed instruction value is equal to dω r_ref =Del_ P - ω r ( P out ), and the reference speed of the speed controller is provided, and the reference torque T ref is output through the PI controller.

[0025] When the output active power of the doubly-fed wind power generator is greater than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed instruction value is ωr_ref =Max ω r , provides a reference speed for the speed controller, and outputs a reference torque through a PI controller T ref .

[0026] Preferably, the droop control is specifically: a droop control system with a negative value, multiplied by the speed deviation, and added to the electromagnetic torque instruction value of the doubly-fed wind power generator; when a frequency disturbance occurs, the reference torque T ref and the additional reference torque ω add together constitute a total reference torque signal T cmd , which is sent to the rotor control model, and finally changes the output electromagnetic torque and active power through the current inner loop of the converter, so as to realize primary frequency regulation of speed control.

[0027] In a second aspect, the embodiment of the present application provides a wind power and thermal power unit combined frequency regulation system based on speed reduction, comprising:

[0028] The load reduction module calculates the maximum power absorption of the wind turbine at different wind speeds and at a constant pitch angle, obtains a maximum power tracking curve below the upper limit of the rotor speed, calculates the load reduction power at different wind speeds at a set load reduction rate d% based on the maximum power tracking curve below the upper limit of the rotor speed, obtains a load reduction power curve below the upper limit of the rotor speed, calculates 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 fits to obtain a suboptimal power tracking curve; and sets a suboptimal power tracking based on the suboptimal power tracking curve to realize suboptimal power output and complete load reduction.

[0029] The frequency regulation module takes the speed deviation of the thermal power unit as a controlled variable for speed frequency regulation; does not trigger the primary frequency regulation of the wind power when the speed deviation of the thermal power unit is within a set range; cooperates with the thermal power unit to participate in the primary frequency regulation through droop control, and realizes combined frequency regulation.

[0030] 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, and the processor implements the steps of the above-mentioned wind power and thermal power unit combined frequency regulation method based on speed reduction when executing the computer program.

[0031] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium comprising a computer program, and the computer program implements the steps of the above-mentioned wind power and thermal power unit combined frequency regulation method based on speed reduction when executed by a processor.

[0032] In a fifth aspect, a chip is provided, which includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and the processor implements the steps of the method for combined frequency modulation of wind power and thermal power units based on speed reduction when executing the computer program.

[0033] In a sixth aspect, an electronic device is provided, which includes a computer program, and the computer program implements the steps of the method for combined frequency modulation of wind power and thermal power units based on speed reduction when executed by the electronic device.

[0034] Compared with the prior art, the present application has at least the following beneficial effects:

[0035] A method for combined frequency modulation of wind power and thermal power units based on speed reduction, in the aspect of wind turbine speed reduction, when the wind speed is low, only speed reduction can meet the requirement of d% reduction rate, and as the wind speed increases, only speed reduction cannot meet the requirement of d% reduction rate, and the frequency modulation effect becomes poor, so it is necessary to combine the frequency modulation of thermal power units; in the aspect of frequency modulation, speed modulation is used in the low wind speed area to ensure the rapid response of primary frequency modulation, and as the wind speed increases, the combined frequency modulation of wind turbine speed modulation and thermal power unit governor is used, which can reduce the damage of overspeed standby to the mechanical structure of the unit when the wind speed is too high, and can also leave sufficient frequency modulation time for the frequency modulation of thermal power units, and when the wind speed exceeds the minimum wind speed in the constant power mode, only the frequency modulation of thermal power units is used, which avoids the damage of overspeed standby to the mechanical structure of the unit when the wind speed is too high, and the present application effectively makes up for the short board of too narrow wind speed power range of speed modulation.

[0036] Further, the inverse function of the obtained reduction power curve ωr-Del_P(ωr) is taken as the suboptimal power tracking curve Del_P-ωr(P), and the reference value of the wind turbine speed is given by the curve, which can ensure that the power absorbed by the wind turbine gradually approaches the suboptimal power at a certain wind speed.

[0037] Further, 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, and at this time, the speed deviation of the synchronous machine can be taken as the system frequency deviation.

[0038] Further, the primary frequency modulation dead zone refers to the insensitive area of the primary frequency modulation unit to the speed near the rated speed. In the real scene, the grid frequency is always fluctuating, in order to prevent the primary frequency modulation response of the unit from being too frequent, the frequency modulation dead zone is set, and when the speed deviation dω is in the corresponding range, the primary frequency modulation of the wind power is not triggered.

[0039] Further, when the output active power of the doubly-fed wind power generator is less than the power absorbed by the wind turbine when the rotor speed is at the upper limit, the rotor speed instruction value is equal to ΔT r_ref=Del P - ω r P out , at this time, the fan can maintain a constant power reduction rate by relying on the speed regulation; when the active power output by the doubly-fed wind power generator is less than the power absorbed by the fan when the rotor speed is at the upper limit, the rotor speed instruction value is equal to ω r_ref =Max ω r At this time, the speed regulation alone cannot maintain a constant power reduction rate, the maximum speed reference value is set to the maximum value that can guarantee the stable operation of the doubly-fed wind power generator and keep the reduction rate within the allowable range.

[0040] Further, the droop control is a control method for implementing the inverter by simulating the droop external characteristic of the synchronous generator in the traditional power system. When the active power output by the inverter changes, the frequency of the inverter output voltage changes linearly according to the droop characteristic curve. Through the droop control, the electromagnetic torque can be dynamically adjusted according to the speed deviation, so that the fan can quickly respond when the system frequency fluctuates, participate in primary frequency modulation together with the thermal power unit, and maintain the stability of the system frequency.

[0041] It can be understood that the beneficial effects of the above-mentioned second aspect to the sixth aspect can be referred to the related description in the first aspect, which will not be repeated here.

[0042] In summary, the application can be used in a system containing a doubly-fed wind power generator and a thermal power unit, and can fully utilize the fast response characteristics of the wind power primary frequency modulation under different wind speed conditions, and can jointly modulate the frequency with the thermal power unit to ensure the stability of the system frequency.

[0043] The technical solutions of the application will be further described in detail below with the help of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments of the present application will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0045] ω Flow chart of wind power and thermal power joint primary frequency modulation of the present application;

[0046] Figure 1 Thermal power unit and fan joint primary frequency modulation system;

[0047] Figure 2 ​A frequency modulation system with only 3 thermal power units participating;

[0048] Figure 3 A comparison of the effects of frequency modulation of a thermal power unit and a combined thermal and wind power unit;

[0049] Figure 4 A schematic diagram of a computer device according to an embodiment of the present application;

[0050] Figure 5 A block diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of the present application.

[0052] In the description of the present application, it should be understood that the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0053] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0054] It should be further understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0055] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe the preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range without departing from the scope of the embodiments of the present application.

[0056] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "when it is determined" or "in response to determining" or "when [a stated condition or event] is detected" or "in response to detecting [a stated condition or event]."

[0057] The various structural diagrams according to the disclosed embodiments of the present application are shown in the drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for clarity and others are omitted. The shapes and relative sizes of the various regions, layers, and the relative positions of these regions / layers shown in the drawings are merely examples, and in actuality, they can be deviated due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0058] The wind turbine adopts rotational speed frequency modulation, and can quickly adjust the output power according to the frequency deviation of the system. In the current research, the energy of the active power released by the wind turbine during frequency disturbance support mainly includes rotor kinetic energy release, overspeed reserve and pitch angle reserve. The traditional active control strategy based on these forms has problems such as less available active reserve, poor economy and poor implementation effect.

[0059] The rotor kinetic energy release only utilizes the inertia power caused by the speed change of the wind turbine itself to support power in a short time of frequency disturbance, and is suitable for improving the short-time frequency support characteristics of wind power, but is difficult to improve the steady-state long-time frequency characteristics; the rotational speed reserve can effectively improve the lowest point of frequency and provide more power support for grid frequency modulation. However, this overspeed reserve control scheme is only suitable for low wind speed, and if the wind speed is high, the overspeed reserve will cause great harm to the mechanical structure of the unit, so this control method has great limitations; in order to make the wind turbine have a certain power reserve at high wind speed, the rotational speed reserve is used in the low wind speed area, the rotational speed is controlled not to be at the maximum power capture point, and the power reserve is left. Due to the fast response characteristics of power electronic devices, the response speed of the frequency change is faster than that of the mechanical governor, but the applicable wind speed range is too narrow.

[0060] Referring to Figure 6 The wind power and thermal power unit combined frequency modulation method based on rotational speed load shedding according to the present application comprises the following steps:

[0061] S1, suboptimal power load shedding

[0062] 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.

[0063] S101. Determine the maximum power tracking curve

[0064] The suboptimal power reduction strategy is based on the wind turbine absorbed power formula Figure 1 r P = f(ω , at a fixed pitch angle ( , Vw, θ) =0). θ r represents the rotor speed, V w is the wind speed, ω This calculation can be used to obtain the wind turbine's absorbed power under different operating conditions, and then to obtain the maximum power point tracking (MPPT) curve below the rotor speed limit. θ r -MAX_ P , providing basic data for subsequent power analysis.

[0065] S102. Determine the load reduction power curve

[0066] 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 for different wind speed scenarios, calculate the corresponding load reduction power ω , thus obtaining the load shedding power curve Del_P r -Del_ ω r ) This step helps 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.

[0067] S103: Determine the suboptimal power tracking curve

[0068] Based on load shedding power curve P(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. rDel P ( ω r ) of the function, i.e. the suboptimal power tracking curve Del P - ω r ( P ) is determined. The determination of the curve provides a basis for subsequent adjustment of the control command according to the actual output power of the fan.

[0069] S104, determining a rotor speed instruction value

[0070] Implementing a suboptimal power tracking strategy, real-time detection of the output active power of the doubly-fed wind power generator P out When P out is less than Del P _Max ω r , the rotor speed instruction value ω r_ref = Del P - ω r ( P out ) is set; when P out is greater than Del P _Max ω r , the value ω r_ref = Max ω r is set. This control logic aims to reasonably adjust the rotor speed according to the output power of the fan, so as to achieve suboptimal power output and improve the frequency regulation performance of the wind-thermal combined system.

[0071] S2, primary frequency regulation of the wind-thermal combined system

[0072] S201, setting the controlled variable of speed regulation

[0073] 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, and at this time the speed deviation of the synchronous machine can be taken as the system frequency deviation, so the speed deviation of the thermal power unit ω is set as the controlled variable of speed regulation.

[0074] S202, setting the primary frequency regulation dead zone

[0075] The speed deviation of the thermal power unit dωSet low-pass filter and dead zone. In a certain range, when the speed deviation dω is in the range, the wind power primary frequency modulation is not triggered. To avoid the system overreaction to the small speed deviation, reduce unnecessary frequency modulation action, improve the stability and reliability of system operation.

[0076] S203, fan frequency modulation control strategy

[0077] Set negative droop control coefficient dω r , the speed deviation Kω is multiplied by dω r Post-added to the electromagnetic torque instruction value of the doubly-fed wind generator T e_ref . Through droop control, the electromagnetic torque can be dynamically adjusted according to the speed deviation, so that the fan can quickly respond when the system frequency fluctuates, cooperates with the thermal power unit to participate in primary frequency modulation, and maintains the stability of the system frequency.

[0078] Those skilled in the art can understand that various aspects of the present application can be implemented as a system, method or program product. Therefore, various aspects of the present application can be implemented in the form of a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software aspects, which can be collectively referred to as "circuit", "module" or "platform" here.

[0079] In another embodiment of the present application, a wind power and thermal power unit combined frequency modulation system based on speed reduction is provided, which can be used to realize the above-mentioned wind power and thermal power unit combined frequency modulation method based on speed reduction. Specifically, the wind power and thermal power unit combined frequency modulation system based on speed reduction includes a load shedding module and a frequency modulation module.

[0080] The load shedding module calculates the maximum power absorption of the fan at different wind speeds and the fixed pitch angle to 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 shedding power at different wind speeds under the set load shedding rate d% is calculated to obtain the load shedding 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 shedding power curve below the upper limit of the rotor speed, and the suboptimal power tracking curve is fitted to obtain the suboptimal power tracking curve; based on the suboptimal power tracking curve, the suboptimal power tracking is set to realize the suboptimal power output and complete the load shedding.

[0081] The frequency modulation module takes the thermal power unit speed deviation as the controlled variable of speed frequency modulation; the thermal power unit speed deviation is not triggered within the set range; through droop control, the thermal power unit cooperates to participate in primary frequency modulation to realize combined frequency modulation.

[0082] In still another embodiment of the present application, a terminal device is provided, which comprises a processor and a memory, the memory being configured to store a computer program, the computer program comprising program instructions, and the processor being configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions to implement a corresponding method flow or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the wind power and thermal power unit combined frequency modulation method based on speed reduction load, comprising:

[0083] The maximum power absorption of the wind turbine at different wind speeds is calculated based on the pitch angle and the maximum power absorption of the wind turbine at different wind speeds, and the maximum power tracking curve below the upper limit of the rotor speed is obtained; the load reduction power at different wind speeds under the set load reduction rate d% is calculated based on the maximum power tracking curve below the upper limit of the rotor speed, and the load reduction power curve below the upper limit of the rotor speed is obtained; the power absorbed by the wind turbine 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 fitted; the suboptimal power tracking is set based on the suboptimal power tracking curve, the suboptimal power output is realized, and the load reduction is completed; the speed deviation of the thermal power unit is used as the controlled variable of the speed frequency modulation; the thermal power unit speed deviation is not excited within the set range; the droop control cooperates with the thermal power unit to participate in the primary frequency modulation, and the combined frequency modulation is realized.

[0084] Please refer to Kω, the terminal device is a computer device, 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 capable of running on the processor 61, and the computer program 63, when executed by the processor 61, implements the method for combined frequency modulation of wind power and thermal power units based on speed droop in the embodiment. To avoid repetition, details are not described here. Alternatively, the computer program 63, when executed by the processor 61, implements the functions of each model / unit in the combined frequency modulation system of wind power and thermal power units based on speed droop in the embodiment. To avoid repetition, details are not described here.

[0085] The computer device 60 can be a desktop computer, a notebook computer, a palm computer, a cloud server, and the like. The computer device 60 can include, but is not limited to, the processor 61 and the memory 62. Those skilled in the art can understand that the computer device 60 can include more or fewer components, or some components can be combined, or different components can be included, for example, the computer device can also include an input / output device, a network access device, a bus, and the like. Figure 5 The computer device 60 is only an example and does not constitute a limitation on the computer device 60, and can include more or fewer components than shown, or some components can be combined, or different components can be included, for example, the computer device can also include an input / output device, a network access device, a bus, and the like.

[0086] The processor 61 can be a central processing unit (CPU), and can also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0087] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or a memory of the computer device 60. The memory 62 can 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, and the like.

[0088] Further, the memory 62 can include both a volatile memory unit and a nonvolatile memory unit. The memory 62 can also include a removable memory unit. The memory 62 is utilized by the computer device 60 to store data and programs and is further utilized to temporarily store output data.

[0089] Referring to Figure 5 , the terminal device 600 is an electronic device in the form of a general purpose computing device. Components of the electronic device can include, but are not limited to, at least one processing unit 610, at least one memory unit 620, a bus 630 that connects the various platform components including the memory unit 620 and the processing unit 610, a display unit 640, and the like.

[0090] The memory unit stores program code that can be executed by the processing unit 610 to cause the processing unit 610 to perform the steps described in the above method section of this specification in accordance with the various example embodiments of this application. For example, the processing unit 610 can perform the steps shown in Figure 6 .

[0091] The memory unit 620 can include a readable medium in the form of volatile memory units, such as a random access memory (RAM) 6201 and / or a cache memory unit 6202, and can further include a read-only memory (ROM) 6203.

[0092] The memory unit 620 can also include a program / utility 6204 having a set of program modules 6205, including but not limited to, an operating system, one or more application programs, other program modules, and program data, and each of these examples, or some combination thereof, can include implementation of a networking environment.

[0093] The bus 630 can be representative of one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration bus, a processor or local bus using any of a variety of bus structures.

[0094] The electronic device 600 can also communicate with one or more external devices 700 such as a keyboard or pointing device, a Bluetooth device, or a database via I / O interface 650. In fact, the electronic device 600 can communicate with any devices (e.g., a router, a modem, a printer, etc.) or one or more entities via I / O interface 650. The I / O interface 650 can include, for example, a mouse interface, a network interface, a video display interface, or an audio interface, among others. In some embodiments, the I / O interface 650 can include one or more devices for allowing a user to interact with the electronic device 600. The electronic device 600 can communicate with one or more networks, such as one or more local area networks (LANs), one or more wide area networks (WANs), and / or one or more public networks, such as the Internet, via network adapter 660. The network adapter 660 can communicate with the other components of the electronic device 600 via bus 630. It should be appreciated that the network adapter 660 and / or the other hardware and / or software components of the electronic device 600 can be configured to operate in accordance with any one or more of the following communication protocols: Bluetooth®, IEEE 802.11, IEEE 802.16, IEEE 802.15, IEEE 802.3, Ethernet, TCP / IP, UDP, HTTP, HTTPS, FTP, SMTP, POP3, IMAP, and / or any other wired and / or wireless communications protocols.

[0095] In another embodiment of the present application, the present application also provides a storage medium, specifically a computer readable storage medium, which is a memory device in the terminal device, used for storing programs and data. It can be understood that the computer readable storage medium herein can include the built-in storage medium in the terminal device, and of course can also include 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 the instructions can be one or more computer programs. It should be noted that the computer readable storage medium herein can be a high-speed RAM memory, or a non-volatile memory, such as at least one disk memory.

[0096] The one or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the wind power and thermal power unit joint frequency modulation method based on speed reduction load shedding in the above embodiments; the one or more instructions stored in the computer readable storage medium are loaded and executed by the processor to implement the following steps:

[0097] The maximum power absorption of the wind turbine under different wind speeds is calculated according to the pitch angle and the maximum power absorption, and the maximum power tracking curve below the upper limit of the rotor speed is obtained; the power reduction under the set power reduction rate d% at different wind speeds is calculated based on the maximum power tracking curve below the upper limit of the rotor speed, and the power reduction curve below the upper limit of the rotor speed is obtained; the power absorption of the wind turbine when the rotor speed is at the upper limit is calculated according to the power reduction curve below the upper limit of the rotor speed, and the suboptimal power tracking curve is fitted to obtain the suboptimal power tracking curve; the suboptimal power tracking is set based on the suboptimal power tracking curve to realize the suboptimal power output and complete the power reduction; the speed deviation of the thermal power unit is taken as the controlled variable of the speed frequency modulation; the thermal power unit speed deviation is not triggered within the set range; the droop control cooperates with the thermal power unit to participate in the primary frequency modulation, and the combined frequency modulation is realized.

[0098] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will be a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0099] Simulation scenario

[0100] The system adopted by the present application is composed of two synchronous generators (including excitation and speed regulator), one wind farm unit and 1503MW load. Among them, the two thermal power units are 900MW capacity, the wind farm unit simulates the equivalent situation of 100 1.5MW double-fed wind turbines, and the load is put into 125MW at 40s and cut off 100MW at 80s, as shown in Figure 1 .

[0101] The system for comparison is composed of three synchronous generators. Among them, steam turbine unit 1 and steam turbine unit 2 are 900MW capacity, and steam turbine unit 3 is 1500MW. The load is put into 125MW at 40s and cut off 100MW at 80s, as shown in Figure 2 .

[0102] Simulation results

[0103] Combination Figure 3The simulation result shows that, compared with the primary frequency modulation of only using the thermal power unit, the primary frequency modulation of using the thermal power unit and the doubly-fed wind power unit based on the speed reduction load can obviously reduce the frequency oscillation peak value caused by the input and cut-off load, and the frequency stable value after reaching the steady state is not much different, which is beneficial to guarantee the frequency stability of the system.

[0104] In summary, the wind power and thermal power unit combined frequency modulation method and system based on the speed reduction load can make the wind power and thermal power generator jointly adjust the active power output of each other according to the load change of the system containing the doubly-fed wind power and thermal power unit. Compared with the frequency modulation of the thermal power generator alone, the combined frequency modulation of the present application can significantly reduce the amplitude of the system frequency jump / drop, and ensure that the variation of the system reference frequency is maintained within a reasonable range.

[0105] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software. In addition, the specific name of each functional unit and module is only for easy distinction, and does not limit the protection scope of the application. The specific working process of the units and modules in the system can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0106] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0107] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0108] In the embodiments of the present application, it should be understood that the disclosed apparatus / terminal and method can be implemented in other manners. For example, the embodiments of the apparatus / terminal described above are merely schematic, and the division of the modules or units is merely logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between the units can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0109] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0110] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can be a physically independent unit, or two or more units can be integrated into a unit. The integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0111] The integrated module / unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, all or part of the flow of the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. When the processor executes the computer program, the steps of each method embodiment described above can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the computer readable medium can include or exclude content according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.

[0112] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 4 one or more flow or blocks Figure One means for functionally implementing the steps in one or more flow or blocks

[0113] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure One one or more flow or blocks Figure One means for functionally implementing the steps in one or more flow or blocks

[0114] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure One one or more flow or blocks Figure One Figure One Figure One means for functionally implementing the steps in one or more flow or blocks

[0115] The above merely provides the technical idea of the present application, and cannot be used to limit the protection scope of the present application. Any modification made according to the technical idea of the present application, on the basis of the technical solutions, falls within the protection scope of the claims of the present application.

Claims

1. A method for combined 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 a fixed pitch angle and different wind speeds, and obtain the maximum power tracking curve below the upper limit of the rotor speed. 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; 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; According to 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, and the suboptimal power tracking curve is obtained by fitting. Specifically, the load reduction power curve ω is obtained by the quadratic function fitting method. r -Del_ P ( ω r ) is used as the inverse function of the suboptimal power tracking curve Del_ P - ω r ( P ); Set up suboptimal power tracking based on the suboptimal power tracking curve to achieve suboptimal power output and complete load reduction; 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 regulation; for the speed deviation of thermal power unit dω Set the low-pass filter and dead zone. When the speed deviation dω is within the corresponding range, the wind power primary frequency regulation will not be triggered. When the output active power of the double-fed wind turbine generator is detected to be 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 ), provides reference speed for the speed controller, and outputs reference torque through PI controller T ref ; When the active power output by the doubly fed wind turbine generator is greater 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 ω r_ref =Max ω r , provides reference speed for the speed controller, and outputs reference torque through PI controller T ref ; The droop control coordinates the thermal power generation units to participate in the primary frequency regulation and realize the joint frequency regulation. The droop control is as follows: set the negative droop control system, multiply it by the speed deviation and add the electromagnetic torque command value of the doubly fed wind turbine; when the frequency disturbance occurs, the reference torque T ref and additional reference torque ΔT add Together they constitute the total reference torque signal T cmd , is sent into the rotor control model, passes through the converter current inner loop, and ultimately changes the output electromagnetic torque and active power, thereby achieving primary frequency modulation of speed control.

2. 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 wind turbine when the rotor speed is at the upper limit is calculated based on 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 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; The suboptimal power tracking curve is as follows: the load shedding power curve ω is obtained by fitting the quadratic function r -Del_ P ( ω r ) is used as the inverse function of the suboptimal power tracking curve Del_ P - ω r ( P ); The frequency regulation module uses the speed deviation of the thermal power unit as the controlled variable for speed frequency regulation. It ensures that the speed deviation of the thermal power unit does not trigger the primary frequency regulation of wind power within the set range. It coordinates the thermal power units to participate in the primary frequency regulation through droop control, thus achieving joint frequency regulation. 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 regulation; for the speed deviation of thermal power unit dω Set the low-pass filter and dead zone. When the speed deviation dω is within the corresponding range, the wind power primary frequency regulation will not be triggered. When the output active power of the double-fed wind turbine generator is detected to be 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 ), provides reference speed for the speed controller, and outputs reference torque through PI controller T ref ; When the active power output by the doubly fed wind turbine generator is greater 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 ω r_ref =Max ω r , provides reference speed for the speed controller, and outputs reference torque through PI controller T ref ; The 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 constitute the total reference torque signal T cmd , is sent into the rotor control model, passes through the converter current inner loop, and ultimately changes the output electromagnetic torque and active power, thereby achieving primary frequency modulation of speed control.

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

4. 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 claim 1.

Images