An accurate frequency modulation system and method applicable to wind power

Abstract

The present invention belongs to the field of electric power, and particularly relates to an accurate frequency modulation system and method applicable to wind power. The system includes: an energy management platform module for connecting a wind turbine group and obtaining corresponding power commands and power values; a wind farm AGC module for providing AGC technology to support the energy management platform module; and a frequency modulation module for outputting a regulation command for the wind turbine group according to the power command and the power value. By providing AGC technology through the wind farm AGC module to support the energy management platform module, the control efficiency can be improved; the energy management platform module connects the wind turbine group and obtains corresponding power commands and power values, which can provide judgment materials for adjusting parameters; and the frequency modulation module outputs a regulation command for the wind turbine group according to the power command and the power value, which can complete accurate frequency modulation of the power grid.

Description

Technical Field

[0001] The present invention belongs to the field of electric power, and particularly relates to an accurate frequency modulation system and method applicable to wind power generation. Background Art

[0002] Wind is a pollution-free energy source. Utilizing wind power generation is very environmentally friendly and can generate a huge amount of electric energy. Therefore, more and more countries attach greater importance to wind power generation. Behind the rapid large-scale development of wind power generation, due to the instability and intermittency of wind energy, a large amount of randomly fluctuating power is injected into the power grid, seriously affecting the stable operation of the power grid system and reducing the stability, power quality, and reliability of the power grid.

[0003] Especially in terms of the frequency of the power grid, the connection of too many wind turbines causes changes in the original power grid structure and power flow distribution. The randomly and rapidly fluctuating wind power makes the power reserve demand required by the power grid to maintain active power balance increase, and higher requirements are imposed on the power grid frequency response ability. The traditional frequency modulation method of thermal power units is restricted and cannot quickly and accurately track power changes, and there will also be a phenomenon of insufficient frequency modulation. Therefore, the connection of a large number of wind turbine groups not only does not have the ability of frequency modulation, but also reduces the response ability of the power grid system, causing the frequency to exceed the limit value when there is a disturbance in the active power of the system, and even the system collapses. The traditional frequency modulation method not only shows deficiencies in the frequency modulation speed, but also cannot meet the increasing usage requirements in terms of the frequency modulation capacity. Summary of the Invention

[0004] In order to solve or improve the above problems, the present invention provides an accurate frequency modulation system and method applicable to wind power, and the specific technical solutions are as follows:

[0005] The present invention provides an accurate frequency modulation system applicable to wind power, including: a wind farm AGC module for providing AGC technology to support the energy management platform module; an energy management platform module for connecting to a wind turbine group and obtaining corresponding power commands and power values; a frequency modulation module for outputting a control command for the wind turbine group according to the power command and the power value.

[0006] Preferably, the energy management platform module includes: a wireless communication unit for transmitting command information to the wind turbine group; and also for realizing chain communication between different energy management platform modules.

[0007] Preferably, the method further includes an energy storage module for storing / outputting thermal-based electric energy; the energy management platform module is used to supplement the insufficient power with the energy storage module when the output power of the wind power grid is insufficient.

[0008] Preferably, the wireless communication unit for transmitting command information to the wind turbine group includes:

[0009] The wireless communication unit is configured to convert the instruction information into a serial signal for transmission to the wind turbine group.

[0010] The present invention provides an accurate frequency modulation method applicable to wind power, which is applicable to the above system and includes: obtaining the power instruction and power value of the wind turbine group through the energy management platform module; setting the wind farm AGC module to control the energy management platform module using AGC technology; and the frequency modulation module outputting a regulation instruction for the wind turbine group according to the power instruction and the power value.

[0011] Preferably, the energy management platform module transmits the instruction information to the wind turbine group based on wireless communication; and chain communication is adopted between the energy management platform modules.

[0012] Preferably, the chain communication adopted between the energy management platform modules includes: the starting energy management platform module outputs a starting AGC instruction signal; other energy management platform modules measure the intensity of the received starting AGC instruction signal, and use the energy management platform module corresponding to the one with the maximum measured intensity as the successor energy management platform module of the communication chain; and the selection process of the successor energy management platform module is repeated in sequence to achieve the chain communication.

[0013] Preferably, when the power output by the wind power grid is insufficient, the insufficient power is supplemented by the thermal power grid.

[0014] Preferably, the method includes: the frequency modulation device directly issues a frequency modulation instruction to the energy management platform to reduce the communication time required for frequency modulation; when the grid frequency exceeds the frequency modulation dead zone, a frequency modulation instruction is calculated by the frequency modulation module and issued to the energy management platform module, and the energy management platform module sends the frequency modulation instruction to each wind turbine group for power adjustment; the wind farm AGC module obtains the power deficit of the grid according to the grid operation condition, then determines the states of each wind turbine group and energy storage module to obtain the maximum adjustable power value, and finally determines the distribution coefficient through the control strategy of the wind farm AGC module.

[0015] Preferably, the determination of the distribution coefficient includes: from the perspective of frequency modulation energy demand, by comparing the sizes of ANTI-RESONANT RING and the parameters of the wind turbine group with the maximum output of the wind farm AGC, the wind turbine groups that require frequency modulation by the wind farm AGC are determined.

[0016] The beneficial effects of the present invention are as follows: By providing AGC technology through the AGC module of the wind farm to support the energy management platform module, the control efficiency can be improved; the energy management platform module is connected to the wind turbine group and obtains the corresponding power command and power value, which can provide judgment materials for adjusting parameters; the frequency modulation module outputs a regulation command for the wind turbine group according to the power command and the power value, and can complete the precise frequency modulation of the power grid. Description of the Drawings

[0017] Figure 1 is a schematic diagram of an accurate frequency modulation system for wind power according to the present invention;

[0018] Figure 2 is a schematic diagram of an accurate frequency modulation method for wind power according to the present invention. Detailed Embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the 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 their combinations.

[0021] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0022] It should be further understood that the term " / and" as used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0023] To solve or improve the problems raised in the background, the present invention provides as Figure 1An accurate frequency modulation system applicable to wind power includes: a wind farm AGC module for providing AGC technology to support the energy management platform module; an energy management platform module for connecting to a group of wind turbines and obtaining corresponding power commands and power values; and a frequency modulation module for outputting a control command for the group of wind turbines according to the power command and the power value.

[0024] The system includes a wind farm AGC module and multiple energy management platform modules. The wind farm AGC module is connected to the energy management platform module through a wired communication method. The wind farm AGC module issues an AGC command to the energy management platform module. The energy management platform controls the connection of a group of wind turbines and an energy storage module. Multiple energy management platforms are connected through wireless communication.

[0025] The system further includes a frequency modulation device. The frequency modulation device communicates directly with the energy management platform module bypassing the wind farm AGC module. The frequency modulation device directly issues a frequency modulation command to the energy management platform. The energy management platform feeds back the power command and power value of the group of wind turbines to the frequency modulation device, reducing the communication time from the wind farm AGC module to the energy management platform module during frequency modulation. When the grid frequency exceeds the frequency modulation dead zone, a frequency modulation command is calculated by the frequency modulation device and issued to the energy management platform module. The energy management platform module sends the frequency modulation command to each group of wind turbines for power adjustment. Among them, automatic generation control (AGC) is an important function in the energy management system (EMS). It controls the output of the frequency modulation unit to meet the continuously changing power demand of users and keep the system in an economic operating state.

[0026] The energy management platform module includes: a wireless communication unit for transmitting command information to the group of wind turbines and for realizing chain communication between different energy management platform modules.

[0027] The method further includes an energy storage module for storing / outputting thermal-based electric energy. The energy management platform module is used to supplement the insufficient power with the energy storage module when the output power of the wind power grid is insufficient.

[0028] The wireless communication unit for transmitting command information to the group of wind turbines includes:

[0029] The wireless communication unit is used to convert the command information into a serial signal for transmission to the group of wind turbines.

[0030] The present invention provides as Figure 2An accurate frequency modulation method applicable to wind power is applicable to the above system, including: S1. Obtain the power command and power value of the fan group through the energy management platform module; S2. Set the wind farm AGC module and use AGC technology to control the energy management platform module; S3. The frequency modulation module outputs a regulation command for the fan group according to the power command and the power value.

[0031] The energy management platform module transmits the command information to the fan group based on wireless communication; the energy management platform modules adopt chain communication.

[0032] The energy management platform modules adopt chain communication, including: the starting energy management platform module outputs a starting AGC command signal; other energy management platform modules measure the intensity of the received starting AGC command signal, and use the energy management platform module corresponding to the one with the maximum measured intensity as the successor energy management platform module of the communication chain; repeat the selection process of the successor energy management platform module in turn to achieve the chain communication.

[0033] The energy management platform module includes a wireless wifi module and a wireless wifi transceiver conversion module. The wireless wifi transceiver conversion module receives the command information sent by the wireless wifi module and converts it into serial communication for transmission to the fan group; multiple energy management platform modules perform chain communication through the wireless wifi module.

[0034] The communication method of multiple energy management platform modules is that the wireless wifi transceiver conversion module of the first energy management platform module sends out the received AGC command signal, the wireless wifi module of each energy management platform module that receives the signal measures its intensity, and intensity comparison is carried out among the energy management platforms. The energy management platform module with the maximum signal intensity is connected to the first wireless wifi transceiver conversion module, and then the wireless wifi module of this energy management platform module measures the signal intensity of other wifi transceiver conversion modules and then connects to the one with the maximum signal intensity, and so on, until the communication connection among all energy management platform modules is completed.

[0035] When the power output by the wind power grid is insufficient, the insufficient power is supplemented by the thermal power grid.

[0036] Specifically, in order to reduce the impact of wind power on natural conditions and reduce the waste of abandoned wind resources, the energy storage systems of wind power generation and thermal power generation are coordinated and regulated. When the output power cannot meet the internal load of the power grid, the remaining power is supplemented by the output of thermal power units and optimized to maintain the internal power balance of the power grid while reducing the exchange power between the distribution network and the microgrid. When optimizing, the exchange power between the wind power grid and the large power grid is P, and the operation optimization is carried out with the output T of the thermal power generation unit and the charge and discharge power F of the energy storage battery. Among them, the output T of the thermal power generation unit is determined by the heat Q of fuel combustion. Q and F are selected as decision variables, the particle dimension is 2 * 24, and the position vector of particle i is expressed as Xi.

[0037] The specific process of optimization is as follows: First step, set the optimization basic parameters, the maximum number of iterations, the maximum and minimum inertia weight coefficients, the learning factor, and the maximum and minimum speeds of the particles;

[0038] Second step, randomly select the position Xi and speed of each particle. From the position of the generated power flow Q selected by the particle, calculate the output T of the thermal power generation unit according to the known initial capacity. If it is not within the range, regenerate the particle;

[0039] Third step, combine the output of the thermal power generation unit, the charge and discharge power of the energy storage battery, and the load demand power to calculate F. The calculation formula is satisfied: F = Pl - Ph - Pw - Pp - Pt. In the above formula, Pl, Ph, Pw, Pp, and Pt are the load demand power, the output power of small hydropower units, the output power of wind turbines, the output power of photovoltaic power generation, and the charge and discharge power of the storage battery respectively;

[0040] Fourth step, calculate the particle fitness value according to the set objective function and compare it to select the individual optimal and global optimal, and record; The calculation method of particle fitness is that the position information and fitness value of each particle are stored in the individual extreme value pb of each particle, pi = (pi, 1, pi, 2,..., pi, d). Select the particle with the optimal fitness in the individual extreme value, and store the position and fitness value of this particle in the global optimal solution gb, pig = (pg, 1, pg, 2,..., pg, d). The fitness function of the particle satisfies the formula In the formula, v is the particle speed, x is the particle position, w is the inertia weight, and the inertia weight affects the exploration and development ability of the particle; c1 and c2 are learning factors, and the learning factors are related to the ability of the particle to learn from the optimal particle in the individual extreme value, and the value is 2; r1 and r2 are random numbers uniformly distributed between 0 and 1. Then compare the current fitness value of all particles with the best position they have been to before. If the current position is better, select it as the current global optimal position. Compare the values of all individual extreme values pb and global optimal solution gb to obtain the optimal solution gb;

[0041] Step 5: Update the particle velocity, position, and inertia weight coefficient, calculate the particle fitness value, compare it with the optimal value, and select the current best position.

[0042] Step 6: Repeat the above steps to update the particle position, velocity, and inertia weight coefficient, and continuously iterate until termination to obtain the optimal solution.

[0043] When frequency modulation is performed on a wind turbine, in order to enable the wind turbine to respond well to changes in the grid frequency and improve the accuracy of frequency regulation of the wind turbine, when the wind speed is lower than or higher than the rated power, torque control and pitch angle control are used respectively. The mechanical power P converted by the wind turbine satisfies the following relationship with the wind speed v, pitch angle α, and rotor speed ω: P = (ρ / 2)A·v3C(η,α); C(η,α) = ∑b ij α i η j ; η = K / (ω / v); In the above formula, ρ is the air density, A is the swept area of the wind turbine blades, C is the wind energy conversion coefficient, η is the tip speed ratio of the wind turbine, K is a conversion constant, and bij is the relationship matrix between C and η.

[0044] The method includes: The frequency modulation device directly issues a frequency modulation command to the energy management platform to reduce the communication time required for frequency modulation; when the grid frequency exceeds the frequency modulation dead zone, the frequency modulation module calculates a frequency modulation command in sequence and issues it to the energy management platform module, and the energy management platform module sends the frequency modulation command to each of the wind turbine groups for power adjustment; the wind farm AGC module obtains the power deficit of the grid according to the grid operation conditions, then determines the states of each of the wind turbine groups and the energy storage module to obtain the maximum power value that can be adjusted, and finally determines the distribution coefficient through the control strategy of the wind farm AGC module.

[0045] The determination of the distribution coefficient includes: From the perspective of frequency modulation energy demand, by comparing the ANTI-RESONANT RING and the parameters of the wind turbine group with the maximum output of the wind farm AGC, the wind turbine group that requires frequency modulation by the wind farm AGC is determined.

[0046] Those of ordinary skill in the art can realize that the units of each example described in combination with the embodiments disclosed in this embodiment can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the components of each example have been generally described according to their functions in the above description. Whether these functions are executed in a hardware or software manner 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 to exceed the scope of the present invention.

[0047] The present invention realizes primary frequency modulation through a frequency modulation device, distributes it to each wind turbine through a wind energy management platform, adds inertial control to the wind farm units to improve the response speed of the units to the given power command; and combines secondary frequency modulation with a large demand for power reserve capacity, and performs secondary frequency modulation on the system according to area control to obtain a reasonable distribution plan; through the wireless communication technology of the energy management platform, it is convenient for the distributed installation of the energy management platform, with a short installation period, getting rid of the bondage of wire harnesses, easy maintenance, and strong expansion ability; by coordinating the rotor speed control and pitch angle control of the fan units, the wind turbines can well respond to the changes in the grid frequency and have a frequency modulation ability similar to that of conventional units.

[0048] In the embodiments provided in the present application, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. An accurate frequency modulation method applicable to wind power, characterized in that, Applicable to an accurate frequency modulation system, including: Obtaining the power command and power value of the wind turbine group through the energy management platform module; Setting up a wind farm AGC module and using AGC technology to control the energy management platform module; The frequency modulation module outputs a regulation command for the wind turbine group according to the power command and the power value; The energy management platform module transmits command information to the wind turbine group based on wireless communication; Chain communication is adopted between the energy management platform modules; Chain communication is adopted between the energy management platform modules, including: The starting energy management platform module outputs a starting AGC command signal; Other energy management platform modules measure the intensity of the received starting AGC command signal, and use the energy management platform module corresponding to the one with the maximum measured intensity as the successor energy management platform module of the communication chain; Repeat the selection process of the successor energy management platform module in sequence to achieve the chain communication; When the power output by the wind power grid is insufficient, the insufficient power is supplemented by the thermal power grid; specifically, the energy storage systems of wind power generation and thermal power generation are coordinated for regulation. When the output power cannot meet the internal load of the power grid, the remaining power is supplied by the output of the thermal power unit and optimized to maintain the internal power balance of the power grid and reduce the exchange power between the distribution network and the microgrid; when optimizing, the exchange power between the wind power generation network and the large power grid is P, and the output of the thermal power generation unit T and the charge and discharge power F of the energy storage battery are optimized for operation. Among them, the output of the thermal power generation unit T is determined by the heat Q of fuel combustion. Q and F are selected as decision variables, the particle dimension is 2*24, and the position vector of particle i is represented as Xi; Then the specific optimization process is: The first step is to set the optimization basic parameters, the maximum number of iterations, the maximum and minimum inertia weight coefficients, the learning factor, and the maximum and minimum speeds of the particles; The second step is to randomly select the position Xi and speed of each particle. From the position of the power generation flow Q selected by the particle, according to the known initial capacity, calculate the output T of the thermal power generation unit. If it is not within the range, generate particles again; The third step is to calculate F by combining the output of the thermal power generation unit, the charge and discharge power of the energy storage battery, and the load demand power. The calculation formula is satisfied: F = Pl - Ph - Pw - Pp - Pt, where Pl, Ph, Pw, Pp, and Pt in the above formula are the load demand power, the output power of the small hydropower unit, the output power of the wind turbine, the output power of the photovoltaic power generation, and the charge and discharge power of the battery, respectively; The fourth step is to calculate the particle fitness value according to the set objective function and compare it, select the individual optimal and global optimal, and record them; The fifth step is to update the particle speed, position, and inertia weight coefficient, calculate the particle fitness value, compare it with the optimal value, and select the current best position; The sixth step is to repeat the above steps to update the particle position, speed, and inertia weight coefficient, and continuously iterate until termination to obtain the optimal solution.

2. The accurate frequency modulation method applicable to wind power according to claim 1, characterized in that, Including: The frequency modulation device directly issues a frequency modulation command to the energy management platform to reduce the communication time required for frequency modulation; When the grid frequency exceeds the frequency modulation dead zone, the frequency modulation module calculates the sequential frequency modulation commands in sequence and sends them to the energy management platform module, and the energy management platform module sends the frequency modulation commands to each of the fan groups for power adjustment; The wind farm AGC module obtains the power deficit of the power grid according to the operation of the power grid, then determines the states of each of the fan groups and the energy storage module to obtain the maximum adjustable power value, and finally determines the distribution coefficient through the control strategy of the wind farm AGC module.

3. The accurate frequency modulation method applicable to wind power according to claim 2, characterized in that, The determination of the distribution coefficient includes: From the perspective of frequency modulation energy demand, by comparing the ANTI-RESONANT RING and the fan group parameters with the maximum output of the wind farm AGC, the fan groups that require the wind farm AGC to perform frequency modulation are determined.

4. An accurate frequency modulation system applicable to wind power, characterized in that, Applying the method according to any one of claims 1-3, includes: An energy management platform module, used to connect to the fan groups and obtain the corresponding power commands and power values; A wind farm AGC module, used to provide AGC technology to support the energy management platform module; A frequency modulation module, used to output a regulation command for the fan groups according to the power command and the power value.

5. The accurate frequency modulation system applicable to wind power according to claim 4, characterized in that, The energy management platform module includes: A wireless communication unit, used to transmit command information to the fan groups; It is also used to realize the chain communication between different energy management platform modules.

6. The accurate frequency modulation system applicable to wind power according to claim 4, characterized in that, It also includes an energy storage module, used to store / output thermal-based electric energy; The energy management platform module is used to supplement the insufficient power with the energy storage module when the output power of the wind power grid is insufficient.

7. The precise frequency modulation system applicable to wind power according to claim 5, wherein, The wireless communication unit, used to transmit command information to the fan groups, includes: The wireless communication unit is used to convert the command information into a serial signal to transmit to the fan groups.

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