Wind storage collaborative frequency modulation device considering power grid primary frequency modulation dead zone

Abstract

The application provides a wind storage collaborative frequency modulation device considering power grid primary frequency modulation dead zone, and has the characteristics that the device comprises a data storage module, which is used for storing parameters of wind turbine generators and battery energy storage as wind storage parameters; a wind storage collaborative frequency modulation dead zone parameter calculation module, which stores preset wind storage combined primary frequency modulation constraints and effect-economy target function data, and is used for calculating the wind storage parameters, the wind storage combined primary frequency modulation constraints and the effect-economy target function through a search algorithm to obtain a dead zone threshold d1 of the battery energy storage and a dead zone threshold d2 of the wind turbine generator; a power grid frequency detection module, which is used for collecting system frequency of a power system; and a wind storage collaborative frequency modulation control module, which is used for performing three-stage dynamic frequency modulation on the power system with large power loss. In summary, the method can achieve the best balance between the effect and economy of the primary frequency modulation of the wind turbine generator and the battery energy storage.

Description

Technical Field

[0001] This invention belongs to the field of power system operation analysis, and specifically relates to a wind-storage coordinated frequency regulation device that takes into account the dead zone of the primary frequency regulation of the power grid. Background Technology

[0002] The proportion of renewable energy power generation in my country's power system is increasing. However, with the grid connection of renewable energy sources such as wind power, which have high uncertainties, the system inertia has decreased significantly, and the frequency regulation capability of traditional units can no longer meet the frequency regulation requirements of a high-proportion renewable energy power system.

[0003] Battery energy storage features fast response and adjustable parameters, enabling it to provide a large amount of active power to low-inertia power systems in a short time to support frequency. Therefore, how to coordinate wind turbines and battery energy storage to jointly participate in the primary frequency regulation of the system is a popular research topic.

[0004] In primary frequency regulation, the regulation capability mainly depends on the governor's droop coefficient, inherent time constants, and adjustable parameters such as dead zone and limiting. The technical regulations and test guidelines for primary frequency regulation of grid-connected power sources clearly stipulate the requirements for primary frequency regulation parameter settings and dynamic performance indicators for various power sources. However, for new power systems with a high proportion of renewable energy, the issue of dead zone parameter setting remains unresolved. Due to the nonlinearity of the dead zone, its impact on primary frequency regulation is not clearly understood. Currently, my country requires dead zone ranges of 0.03–0.10 Hz for wind turbines and 0.03–0.05 Hz for energy storage. Some scholars have pointed out the impact of different dead zone parameter settings on frequency regulation performance, but this has only been verified through simple qualitative analysis or extensive simulations, without analyzing the mechanistic effects of dead zone nonlinearity. Therefore, considering the setting of reasonable primary frequency regulation dead zone parameters is of great significance for frequency stability.

[0005] Most existing technologies focus on setting the frequency modulation dead zone parameters for a single frequency modulation resource, with few studies on dead zone coordination. Furthermore, most current research employs the describing function method based on frequency domain analysis, which can only be used to study the frequency domain characteristics of the system.

[0006] In summary, existing technologies cannot enable wind-storage coordinated primary frequency regulation to achieve both frequency regulation effectiveness and cost-effectiveness. Summary of the Invention

[0007] This invention is made to solve the above-mentioned problems, and its purpose is to provide a wind-storage coordinated frequency regulation device that takes into account the dead zone of the primary frequency regulation of the power grid.

[0008] This invention provides a wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid. It is used to control multiple wind turbines and battery energy storage to perform primary frequency regulation of the power system. The device includes: a data storage module for storing parameters of the wind turbines and battery energy storage as wind-storage parameters; a wind-storage coordinated frequency regulation dead zone parameter calculation module, storing preset data on wind-storage joint primary frequency regulation constraints and effect-economy objective functions, used to calculate the wind-storage parameters, wind-storage joint primary frequency regulation constraints, and effect-economy objective functions using a search algorithm to obtain the dead zone threshold d1 of the battery energy storage and the dead zone threshold d2 of the wind turbines; and a power grid frequency detection module for collecting power system data. The system frequency; the wind-storage coordinated frequency regulation control module is used to perform three-stage dynamic frequency regulation for power systems experiencing large power outages. The specific process of dynamic frequency regulation is as follows: When the system frequency is less than or equal to the dead zone threshold d1 (the first stage), the wind-storage coordinated frequency regulation control module controls all wind turbines and battery energy storage to remain inactive; when the system frequency is greater than the dead zone threshold d1 and less than or equal to the dead zone threshold d2 (the second stage), the wind-storage coordinated frequency regulation control module controls all battery energy storage to generate active power; when the system frequency is greater than the dead zone threshold d2 (the third stage), the wind-storage coordinated frequency regulation control module controls all wind turbines and battery energy storage to generate active power. The expression for the effect-economy objective function is: In the formula, minΔf max (d1, d2) is to make Δf max Minimum, Δf max To define the maximum frequency deviation when wind turbines and battery storage are sequentially deployed for primary frequency regulation, minJ(d1, d2) is the value that minimizes the sum of J1 and J2, where J1 is the primary frequency regulation cost of the wind turbine and J2 is the primary frequency regulation cost of the battery storage. w Let n be the number of wind turbine units. b ΔP represents the number of battery storage units, a1 is the cost adjustment coefficient for wind turbine power deviation, a2 and a3 are the cost adjustment coefficients considering battery energy storage charging and discharging and SoC deviation, respectively. w，i (t) represents the change in active power output of the i-th wind turbine at time t, ΔP b，i (t) represents the change in active power output of the i-th battery storage unit at time t, SoC i Let SoC be the i-th battery energy storage SoC, and SoC0 be the initial SoC state of the battery energy storage.

[0009] The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid provided by this invention may also have the following feature: wherein the maximum frequency deviation Δf max The expression for the time-domain solution Δf1(t) of the frequency deviation, calculated based on the dynamic frequency modulation, is as follows: In the formula, R is the static droop coefficient of the thermal power unit, and ΔP L For step power disturbance, D is the damping coefficient, α is the capacity ratio of wind turbine, β is the capacity ratio of battery storage, and K b K is the primary frequency regulation coefficient set during battery energy storage frequency regulation. w The primary frequency regulation coefficients are set for wind turbine frequency regulation. C1, C2, C3, C4, C5, and C6 are undetermined constants, λ1, λ2, λ3, λ4, λ5, and λ6 are the roots of the characteristic equation, and the maximum frequency deviation Δf is the value of the coefficient. max The expression is: Δf max =max{Δf 1，max , Δf 2，max}, In the formula Δf 1，max The maximum frequency deviation during the second stage, t 1，max Δf represents the moment when the system frequency reaches its lowest point during the second stage. 2，max The maximum frequency deviation during the third stage, t 2，max This refers to the moment when the system frequency reaches its lowest point during the third stage.

[0010] The wind-storage coordinated frequency regulation device considering the dead zone of the primary frequency regulation of the power grid provided by this invention may also have the following feature: wherein the wind-storage joint primary frequency regulation constraint includes power balance constraint, generator set constraint, battery energy storage constraint, wind turbine set constraint, dead zone range constraint, and primary frequency regulation effect constraint, and the expression of the power balance constraint is: In the formula P G (t) represents the generator output at time t, P w，i (t) represents the active power output of the i-th wind turbine at time t, P b，i (t) represents the active power output of the i-th battery at time t, P L (t) represents the load disturbance, and the expression for the generator set constraint is: In the formula This represents the lower limit of the generator set's output. Given the upper limit of generator output, the expression for the battery energy storage constraint is: In the formula Let i be the lower limit of the active power output of the i-th battery. Let SoC(t) be the upper limit of the active power output of the i-th battery storage unit, and let SoC(t) be the value of the battery storage SoC at time t. min For the minimum value of the battery energy storage SoC, SoC max The expression for the constraint on the wind turbine is: (This is the maximum value of the battery energy storage SoC) In the formula This represents the lower limit of the active power output of the i-th wind turbine. The expression for the dead zone constraint, which represents the upper limit of the active power output of the i-th wind turbine, is as follows: The expression for the constraint on the effect of primary frequency modulation is: In the formula This is the lower limit of the permissible frequency for a single frequency modulation. Δf represents the upper limit of the allowed frequency for a single frequency modulation, and Δf represents the frequency deviation.

[0011] The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid provided by this invention may also have the following feature: wherein the expression for the battery energy storage SoC value SoC(t) at time t is: In the formula ΔP b (t) represents the change in active power output of the battery at time t, E rated The rated capacity for battery energy storage.

[0012] The wind-storage coordinated frequency regulation device considering the dead zone of the primary frequency regulation of the power grid provided by this invention may also have the following features: wherein the search algorithm is an improved multi-objective particle swarm optimization algorithm, and the specific steps for obtaining the dead zone thresholds d1 and d2 are as follows: Step S1, initialize the velocity and position of the particles according to the wind-storage parameters; Step S2, calculate the particle fitness value of the particles according to the wind-storage joint primary frequency regulation constraints and the effect-economy objective function, obtain the individual optimal value of the particles, and then obtain the population global optimal value for this iteration based on the individual optimal value; Step S3, determine whether the maximum number of iterations is satisfied. If yes, proceed to step S5; if no, proceed to step S4; Step S4, optimize the position of the particles according to the learning factor, and optimize the velocity of the particles according to the inertia weight, and then proceed to step S2; Step S5, select the leading population global optimal value from all population global optimal values, and then obtain the dead zone thresholds d1 and d2 according to the optimal compatible solution optimization method.

[0013] The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid provided by this invention may also have the following feature: wherein the parameter settings of the improved multi-objective particle swarm algorithm include a particle number of 50, c max The value is 2, c min The value is 0.2, w max The value is 0.9, w min The value is 0.4, and the maximum number of iterations is 100.

[0014] The role and effect of invention

[0015] According to the wind-storage coordinated frequency regulation device considering the dead zone of the primary frequency regulation of the power grid, based on wind and storage parameters, and through the IMOPSO algorithm combined with an effect-economy objective function and joint wind-storage primary frequency regulation constraints, multiple optimal combinations of dead zone thresholds d1 and d2 are obtained. Furthermore, an optimal compatibility solution optimization method is used to obtain dead zone thresholds d1 and d2 that balance frequency regulation effect and economy from all optimal combinations. The wind turbine and energy storage battery are then controlled to dynamically regulate the frequency based on these dead zone thresholds d1 and d2. Therefore, the wind-storage coordinated frequency regulation device considering the dead zone of the primary frequency regulation of the power grid can achieve an optimal balance between the effect and economy of primary frequency regulation of wind turbines and battery energy storage. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the frame of the wind-storage coordinated frequency regulation device in an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the process of obtaining the dead zone thresholds d1 and d2 according to the IMOPSO algorithm in an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of a wind-storage frequency response model containing a primary frequency regulation dead zone in an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of the lowest frequency point in the dynamic frequency modulation in an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of an IEEE four-machine two-zone system in an embodiment of the present invention;

[0021] Figure 6 This is a schematic diagram of the Pareto front in an embodiment of the present invention. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the wind-storage coordinated frequency regulation device of the present invention that considers the primary frequency regulation dead zone of the power grid.

[0023] Figure 1 This is a schematic diagram of the wind-storage coordinated frequency regulation device in an embodiment of the present invention.

[0024] like Figure 1 As shown, in this embodiment, the wind-storage coordinated frequency regulation device 100, which considers the dead zone of the primary frequency regulation of the power grid, is used to control multiple wind turbines and battery energy storage to perform primary frequency regulation of the power system. It includes a data storage module 10, a wind-storage coordinated frequency regulation dead zone parameter calculation module 20, a power grid frequency detection module 30, and a wind-storage coordinated frequency regulation control module 40.

[0025] The data storage module 10 is used to store the parameters of the wind turbine and battery energy storage as wind-storage parameters.

[0026] The wind-storage coordinated frequency regulation dead zone parameter calculation module 20 stores preset data on wind-storage joint primary frequency regulation constraints and effect-economy objective functions. It is used to calculate the wind-storage parameters, wind-storage joint primary frequency regulation constraints, and effect-economy objective functions through a search algorithm to obtain the dead zone threshold d1 of battery energy storage and the dead zone threshold d2 of wind turbine.

[0027] The search algorithm used is an improved multi-objective particle swarm optimization (IMOPSO) algorithm. The parameters of the improved IMOPSO algorithm include a particle number of 50 and c. max The value is 2, c min The value is 0.2, w max The value is 0.9, w min The value is 0.4.

[0028] Figure 2 This is a schematic diagram of the process of obtaining the dead zone thresholds d1 and d2 according to the IMOPSO algorithm in an embodiment of the present invention.

[0029] like Figure 2 As shown, obtaining the dead zone thresholds d1 and d2 according to the IMOPSO algorithm includes the following steps:

[0030] Step S1: Initialize the velocity and position of the particles based on the wind storage parameters.

[0031] Step S2: Calculate the particle fitness value of the particles based on the wind-storage joint primary frequency regulation constraint and the effect-economy objective function, obtain the individual optimal value of the particles, and then obtain the population global optimal value for this iteration based on the individual optimal value.

[0032] Step S3: Determine if the maximum number of iterations is met. If yes, proceed to step S5; otherwise, proceed to step S4.

[0033] The maximum number of iterations is 100.

[0034] Step S4: Optimize the particle position based on the learning factor and optimize the particle velocity based on the inertia weight, then proceed to step S2.

[0035] Step S5: Select the leading global optimum from all global optimum values ​​of the population, and then obtain the dead zone thresholds d1 and d2 according to the optimal compatible solution optimization method.

[0036] The power grid frequency detection module 30 is used to collect the system frequency of the power system.

[0037] The wind-storage coordinated frequency regulation control module 40 is used for three-stage dynamic frequency regulation of power systems experiencing large power outages.

[0038] In this embodiment, during dynamic frequency regulation, battery energy storage and wind turbines are put into operation in batches to fully leverage the advantages of battery energy storage, such as fast response speed and strong ramping capability, providing strong frequency support for the system in the early stages of disturbance. Therefore, the three stages of dynamic frequency regulation are divided into dead zone thresholds d1 and d2. The specific process of dynamic frequency regulation in the three stages is as follows:

[0039] When the system frequency is less than or equal to the dead zone threshold d1, i.e., during the first stage 0 to t0, the wind-storage coordinated frequency regulation control module 40 controls all wind turbines and battery energy storage to remain inactive.

[0040] When the system frequency is greater than the dead zone threshold d1 and less than or equal to the dead zone threshold d2, i.e., during the second stage t0 to t1, the wind-storage coordinated frequency regulation control module 40 controls all battery energy storage to perform active power output.

[0041] When the system frequency is greater than the dead zone threshold d2, i.e. after the third stage t1, the wind-storage coordinated frequency regulation control module 40 controls all wind turbines and battery energy storage to generate active power.

[0042] The derivation process of the effect-economy objective function applicable to this dynamic frequency modulation in this embodiment is as follows:

[0043] I. Objective Function

[0044] During dynamic frequency modulation, higher modulation speed is required in the initial stage of disturbance, and battery energy storage can precisely control output power, which conforms to the characteristics of a step dead zone model. Therefore, a step dead zone is adopted for battery energy storage. The expressions for the input and output of the battery energy storage frequency modulation dead zone are as follows:

[0045]

[0046] In the formula x b (t) is the dead-zone output of battery energy storage frequency regulation at time t, and Δf(t) is the dead-zone input of battery energy storage frequency regulation at time t.

[0047] Considering the impact of wind speed uncertainty on wind turbine frequency regulation, using a standard dead zone can effectively reduce wind turbine wear and improve frequency regulation economy. Therefore, the expressions for the input and output of the wind turbine frequency regulation dead zone are as follows:

[0048]

[0049] In the formula x w (t) represents the frequency regulation dead zone output of the wind turbine at time t, and Δf(t) represents the frequency regulation dead zone input of the wind turbine at time t.

[0050] Figure 3 This is a schematic diagram of a wind-storage frequency response model containing a primary frequency regulation dead zone in an embodiment of the present invention.

[0051] like Figure 3 As shown, a wind-storage frequency response model is constructed for battery energy storage, wind turbine, and combined thermal power unit. The output Δf is obtained by subtracting the input ΔP(t) from the output power of battery energy storage, wind turbine, and thermal power unit, and then passing the coefficients. M is the inertial time constant, and D is the damping coefficient.

[0052] The converted primary frequency regulation output power ΔP of the wind turbine w The expression for (t) is:

[0053] ΔP w (t)=-αK w x w (t),

[0054] In the formula, α represents the capacity ratio of wind turbine units, and K w The primary frequency regulation coefficient, x, is set when regulating the frequency of a wind turbine. w (t) is the step-type dead zone.

[0055] The converted battery energy storage primary frequency regulation output power ΔP b The expression for (t) is:

[0056] ΔP b (t)=-βK b x b (t),

[0057] In the formula, β represents the capacity ratio of battery energy storage, and K b The primary frequency regulation coefficient, x, is set for frequency regulation during battery energy storage. b (t) refers to the ordinary dead zone.

[0058] The converted output power of the thermal power unit ΔP G The expression for (t) is:

[0059]

[0060] In the formula F H T represents the percentage of the high-pressure cylinder's output power to the total turbine output. R R is the intermediate reheat steam volume time constant of the thermal power unit, and R is the static droop coefficient of the thermal power unit.

[0061] The aforementioned nonlinear wind-storage frequency response model can be transformed into several linear models according to different stages of dynamic frequency regulation. By ensuring continuity before and after the boundary point through analytical solution, a model containing state variables x can be established. w (t), x bThe time-domain differential equations for f(t) and Δf(t) are as follows:

[0062]

[0063] In the formula ΔP L (t) represents the step power disturbance. Let be the impulse function.

[0064] Based on the above time-domain differential equation, a piecewise linearization solution can be conveniently performed using the dead zone. The expression for the time-domain solution Δf1(t) of the frequency deviation in the three stages of dynamic frequency modulation can be obtained as follows:

[0065]

[0066] In the formula, C1, C2, C3, C4, C5, and C6 are undetermined constants, and λ1, λ2, λ3, λ4, λ5, and λ6 are the roots of the characteristic equation.

[0067] Figure 4 This is a schematic diagram of the lowest frequency point in the dynamic frequency modulation in an embodiment of the present invention.

[0068] like Figure 4 As shown, Case 1 and Case 2 represent the frequency-time curves of the lowest frequency point during dynamic frequency modulation in the second and third stages, respectively. The horizontal axis of both Case 1 and Case 2 is time (t), and the vertical axis is frequency (Hz). Both Case 1 and Case 2 have three primary frequency modulation index points, representing RoCoF (0), the lowest frequency point, and the quasi-steady-state frequency, respectively. Both Case 1 and Case 2 also have two primary frequency modulation activation points, representing t0 and t1, respectively. Therefore, depending on the frequency modulation resource allocation, the lowest frequency point during dynamic frequency modulation may occur in the second or third stage. The corresponding expression for the maximum frequency deviation is as follows:

[0069] The lowest frequency occurs in the second stage, let The simplified expression for finding the frequency at its lowest point is as follows:

[0070]

[0071] The maximum frequency deviation Δf during the second stage 1，max The expression is:

[0072]

[0073] The lowest frequency occurs in the second stage, let The simplified expression for finding the frequency at its lowest point is as follows:

[0074]

[0075] The maximum frequency deviation Δf during the third stage 2，max The expression is:

[0076]

[0077] Combining the above two scenarios, the maximum frequency deviation Δf when the wind and storage are sequentially put into operation for one frequency regulation can be obtained. max The expression is: Δf max =max{Δf 1，max , Δf 2，max The maximum frequency deviation Δf max That is, the effect objective function in the effect-economy objective function.

[0078] II. Economic Objective Function

[0079] For wind turbines, increasing or decreasing power during dynamic frequency regulation will change the pitch angle, and adjusting the pitch angle will cause varying degrees of mechanical wear. Therefore, the frequency regulation cost is designed based on the quadratic function of the wind turbine power deviation. The expression for the primary frequency regulation cost J1 of the wind turbine is as follows:

[0080]

[0081] In the formula, a1 is the cost adjustment coefficient for wind turbine power offset, and ΔP w，i (t) represents the change in active power output of the i-th wind turbine at time t, n w This represents the number of wind turbine units.

[0082] For battery energy storage, during dynamic frequency regulation, the cost comes from the degradation of cycle life and battery aging caused by high power and large SoC offset. The expression for the battery energy storage SoC value SoC(t) at time t is:

[0083]

[0084]

[0085] In the formula ΔP b (t) represents the change in active power output of the battery at time t, E rated SoC0 represents the rated capacity of the battery energy storage, while SoC0 represents the initial SoC state of the battery energy storage.

[0086] The frequency regulation cost of battery energy storage consists of two parts: a quadratic function of power deviation and SoC deviation. Therefore, the expression for the primary frequency regulation cost J2 of battery energy storage is:

[0087]

[0088] In the formula n bLet a1 be the number of battery storage units, a2 be the cost adjustment coefficients considering battery charging / discharging and SoC deviation, and ΔP be the cost of the battery storage units. b，i (t) represents the change in active power output of the i-th battery storage unit at time t, SoC i The SoC is the energy storage for the i-th battery.

[0089] The economic objective function can be expressed as follows, based on the primary frequency regulation cost J2 of battery energy storage and the primary frequency regulation cost J1 of wind turbine:

[0090] minJ(d1, d2) = J1 + J2.

[0091] In summary, the expression for the effect-economy objective function is:

[0092]

[0093] Furthermore, in order to calculate the dead zone thresholds d1 and d2 based on the effect-economy objective function, it is also necessary to construct a joint wind-storage primary frequency regulation constraint, which specifically includes:

[0094] The power balance constraint is expressed as follows:

[0095]

[0096] In the formula P G (t) represents the generator output at time t, P w，i (t) represents the active power output of the i-th wind turbine at time t, P b，i (t) represents the active power output of the i-th battery at time t, P L (t) represents the load disturbance.

[0097] The generator set constraints are expressed as follows:

[0098]

[0099] In the formula This represents the lower limit of the generator set's output. This is the upper limit of the generator set's output.

[0100] The battery energy storage constraint is expressed as follows:

[0101]

[0102] In the formula Let i be the lower limit of the active power output of the i-th battery. Let SoC(t) be the upper limit of the active power output of the i-th battery storage unit, and let SoC(t) be the value of the battery storage SoC at time t. min For the minimum value of the battery energy storage SoC, SoC maxThis represents the maximum value of the battery energy storage SoC.

[0103] The constraints of the wind turbine generator are expressed as follows:

[0104]

[0105] In the formula This represents the lower limit of the active power output of the i-th wind turbine. This represents the upper limit of the active power output of the i-th wind turbine.

[0106] The dead zone constraint is expressed as follows:

[0107]

[0108] The expression for the first frequency modulation effect constraint is:

[0109]

[0110] In the formula This is the lower limit of the permissible frequency for a single frequency modulation. Δf represents the upper limit of the allowed frequency for a single frequency modulation, and Δf represents the frequency deviation.

[0111] To evaluate the effectiveness of the dead zone thresholds d1 and d2 calculated by the wind-storage coordinated frequency regulation dead zone parameter calculation module 20 in this embodiment, the following simulation tests were conducted:

[0112] An IEEE four-machine two-zone system was built as a power system on the MATLAB / Simulink simulation platform.

[0113] Figure 5 This is a schematic diagram of an IEEE four-machine two-zone system in an embodiment of the present invention.

[0114] like Figure 5 As shown, the IEEE four-machine two-zone system includes Zone 1 and Zone 2. Zone 1 includes a synchronous generator set G1 with a rated capacity of 150MW, a synchronous generator set G2 with a rated capacity of 200MW, and a wind farm with a rated capacity of 150MW, i.e., wind turbines. The wind farm consists of 100 DFIG units with a rated capacity of 1.5MW. The steady-state load of Zone 1, i.e., load 1, is 175MW. Zone 2 includes a synchronous generator set G3 with a rated capacity of 100MW and a battery energy storage with a rated capacity of 12MW / 3MW·h.

[0115] For the sudden increase of 60MW of disturbance load in region 2, i.e. load 3, a large power loss occurs in the power system. The values ​​of the parameters in the table below are used as the values ​​of the parameters corresponding to the wind-storage joint primary frequency regulation constraint and the effect-economy objective function. Combined with the IMOPSO method, multiple groups of global optimal values, i.e. dead zone thresholds d1 and d2, are obtained.

[0116]

[0117]

[0118] In the table above, the first and third columns are parameters, the second column is the value of the parameter corresponding to the first column, and the fourth column is the value of the parameter corresponding to the third column.

[0119] Figure 6 This is a schematic diagram of the Pareto front in an embodiment of the present invention.

[0120] like Figure 6 As shown, the horizontal axis represents the primary effect objective function of wind storage, i.e., the calculated result of the effect objective function at the dead zone thresholds d1 and d2. The vertical axis represents the primary economic objective function of wind storage, i.e., the calculated result of the economic objective function at the dead zone thresholds d1 and d2. The Pareto front represents the frontier combination pairs among all combination pairs calculated by the IMOPSO method. Each frontier combination pair represents the optimal effect of the calculated results of the economic objective function and the effect objective function at the given dead zone threshold. Three different dead zone threshold schemes, A, B, and C, were selected from the frontier, and the corresponding objective functions were calculated. The results are shown in the table below:

[0121] A 0.0302 0.0303 0.2739 0.8737 B 0.0386 0.0579 0.2816 0.8257 C 0.0497 0.9983 0.2979 0.8025

[0122] The first column in the table above is the scheme number, the second column is the dead zone threshold d1 of the corresponding scheme, the third column is the dead zone threshold d2 of the corresponding scheme, the fourth column is the result of the objective function calculation of the corresponding scheme, and the fifth column is the result of the objective function calculation of the corresponding scheme. For example, the cell in the third row and second column indicates that the dead zone threshold corresponding to scheme B in the Pareto front diagram is 0.0386.

[0123] As shown in the table above, Scheme A has the best objective function calculation results when considering only the single objective optimization of the wind-storage primary frequency regulation effect. The dead zone setting of the wind-storage primary frequency regulation is close to the lower limit value given in the national standard, and the maximum frequency deviation is 0.2739Hz. However, the frequency regulation economy is also the worst. Compared with Scheme B and Scheme C, the frequency regulation cost increases by 5.85% and 8.87%, respectively.

[0124] Scheme C, which only considers the single-objective optimization of the economic efficiency of wind-storage primary frequency regulation, has the best economic objective function calculation results. The dead zone setting of wind-storage primary frequency regulation is close to the upper limit value given in the national standard, but the frequency regulation effect is the worst at this time, with the maximum frequency deviation reaching 0.2979Hz.

[0125] Scheme B, which is the dead zone threshold d1 of battery storage and the dead zone threshold d2 of wind turbine obtained from all frontier values ​​according to the optimal compatibility solution optimization method in this embodiment, is a multi-objective optimization that comprehensively considers the primary frequency regulation effect and frequency regulation economy of wind and energy storage. At this time, the maximum frequency deviation is 0.2816Hz, and the frequency regulation cost is reduced by 5.53% and increased by 2.85% compared with Scheme A and Scheme C, respectively. It can fully coordinate the contradiction between the primary frequency regulation effect and economy of wind and energy storage and has more advantages.

[0126] In summary, by constructing a power system on a simulation platform and calculating the dead zone thresholds d1 and d2 based on the wind and energy storage parameters of the power system, it can be seen that the dead zone thresholds d1 and d2 calculated by the wind and energy storage coordinated frequency regulation dead zone parameter calculation module 20 of this embodiment can better coordinate the contradiction between performance and economy compared with other dead zone thresholds, and have a superior balance.

[0127] The role and effect of the embodiments

[0128] According to the wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid involved in this embodiment, based on wind and storage parameters, and using the IMOPSO algorithm combined with the effect-economy objective function and the joint primary frequency regulation constraint of wind and storage, multiple optimal combinations of dead zone thresholds d1 and d2 are obtained. Furthermore, the optimal compatibility solution optimization method is used to obtain dead zone thresholds d1 and d2 that balance frequency regulation effect and economy from all optimal combinations. The wind turbine and energy storage battery are then controlled to dynamically regulate the frequency based on these dead zone thresholds d1 and d2. In summary, this method can achieve the best balance between the effect and economy of primary frequency regulation of wind turbines and battery energy storage.

[0129] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid, used to control multiple wind turbines and battery energy storage to perform primary frequency regulation of the power system, characterized in that, include: A data storage module is used to store the parameters of the wind turbine and the battery energy storage as wind-storage parameters; The wind-storage coordinated frequency regulation dead zone parameter calculation module stores preset data on wind-storage joint primary frequency regulation constraints and effect-economy objective functions. It is used to calculate the dead zone threshold of the battery storage by using a search algorithm on the wind-storage parameters, the wind-storage joint primary frequency regulation constraints, and the effect-economy objective function. and the dead zone threshold of the wind turbine ; A power grid frequency detection module is used to collect the system frequency of the power system; The wind-storage coordinated frequency regulation control module is used to perform three-stage dynamic frequency regulation on the power system experiencing a large power outage. The specific process of dynamic frequency modulation is as follows: The system frequency is less than or equal to the dead zone threshold. In the first stage, the wind-storage coordinated frequency regulation control module controls all wind turbines and battery energy storage to remain inactive. The system frequency is greater than the dead zone threshold. And less than or equal to the dead zone threshold In the second stage, the wind-storage coordinated frequency regulation control module controls all the battery energy storage units to output active power. The system frequency is greater than the dead zone threshold. In the third stage, the wind-storage coordinated frequency regulation control module controls all the wind turbines and battery energy storage to output active power. The expression for the effect-economy objective function is: ， ， ， In the formula In order to make Minimum, The maximum frequency deviation when wind and storage are sequentially put into frequency regulation. In order to make and The sum is the smallest. The cost of primary frequency regulation for wind turbine units, The cost of frequency regulation for battery energy storage The number of wind turbine units. The number of cells that can store energy. This is the cost adjustment coefficient for wind turbine power deviation. , These are cost adjustment coefficients that take into account battery energy storage charging and discharging as well as SoC deviation. for Time of the first Changes in the active power output of typhoon generators for Time of the first Changes in the active power output of Taiwan's battery energy storage system. For the first Taiwan's battery energy storage SoC, This represents the initial SoC state for battery energy storage.

2. The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid according to claim 1, characterized in that: in, The maximum frequency deviation The frequency deviation time-domain solution constructed based on the dynamic frequency modulation Calculations show that The frequency deviation time-domain solution The expression is: ， In the formula This refers to the static droop coefficient of a thermal power unit. For step power disturbance, The damping coefficient is... The proportion of wind turbine capacity. This refers to the percentage of battery energy storage capacity. The primary frequency regulation coefficient set for battery energy storage frequency regulation. This is the primary frequency regulation coefficient set when regulating the frequency of a wind turbine. , , , , , They are undetermined constants, , , , , , These are the roots of the characteristic equation. The maximum frequency deviation The expression is: ， ， ， ， ， In the formula This represents the maximum frequency deviation during the second stage. This refers to the moment when the system frequency reaches its lowest point during the second stage. This represents the maximum frequency deviation during the third stage. This refers to the moment when the system frequency reaches its lowest point during the third stage.

3. The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid according to claim 1, characterized in that: in, The combined wind and energy storage primary frequency regulation constraints include power balance constraints, generator set constraints, battery storage constraints, wind turbine set constraints, dead zone constraints, and primary frequency regulation effect constraints. The expression for the power balance constraint is: ， In the formula for Generator output at all times for Time of the first The typhoon generator has active power output. for Time of the first Taiwan's battery energy storage system has active power output. For load disturbance, The expression for the generator set constraint is: ， In the formula This represents the lower limit of the generator set's output. This is the upper limit of the generator set's output. The expression for the battery energy storage constraint is: ， In the formula For the first The lower limit of active power output of Taiwan's battery energy storage system. For the first Taiwan's battery energy storage system has a maximum active power output limit. for Battery energy storage The value, For battery energy storage The minimum value, For battery energy storage The maximum value, The expression for the wind turbine constraint is: ， In the formula For the first Lower limit of active power output of typhoon generator units For the first The maximum active power output of typhoon generator units. The expression for the dead zone range constraint is: ， The expression for the primary frequency modulation effect constraint is: ， In the formula This is the lower limit of the permissible frequency for a single frequency modulation. This is the upper limit of the allowed frequency for a single frequency modulation. This represents the frequency deviation.

4. The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid according to claim 3, characterized in that: in, The Battery energy storage value The expression is: ， ， In the formula for The change in active power output of battery energy storage at any given time. The rated capacity for battery energy storage.

5. The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid as described in claim 1, Its features are: in, The search algorithm is an improved multi-objective particle swarm optimization algorithm. The dead zone threshold is obtained. and the dead zone threshold The specific steps are as follows: Step S1: Initialize the velocity and position of the particles according to the wind storage parameters; Step S2: Calculate the particle fitness value of the particle based on the wind-storage joint primary frequency regulation constraint and the effect-economy objective function, obtain the individual optimal value of the particle, and then obtain the population global optimal value for this iteration based on the individual optimal value. Step S3: Determine whether the maximum number of iterations is met. If yes, proceed to step S5; otherwise, proceed to step S4. Step S4: Optimize the position of the particle according to the learning factor and optimize the velocity of the particle according to the inertia weight, and then proceed to step S2; Step S5: Select the leading global optimum from all the global optimum values ​​of the population, and then obtain the dead zone threshold according to the optimal compatible solution selection method. and the dead zone threshold .

6. The wind-storage coordinated frequency regulation device considering the primary frequency regulation dead zone of the power grid according to claim 5, characterized in that: in, The parameter settings for the improved multi-objective particle swarm optimization algorithm include a particle number of 50. The value is 2. The value is 0.

2. The value is 0.

9. The value is 0.4, and the maximum number of iterations is 100.

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