Method and system for full-range participation of energy storage charging and discharging in power grid frequency regulation

Abstract

Disclosed in the present invention are a method and system for full-range participation of energy storage charging and discharging in power grid frequency regulation. The method comprises: collecting operating power and frequency data of a power grid, so as to construct a full-range droop coefficient; setting constraints for an upper limit value and a lower limit value of a frequency dead band; obtaining an actual output power instruction value by means of a constraint function constructed on the basis of a theoretical power instruction value and a charging / generated power rated value, and controlling the power grid to operate on the basis of the actual output power instruction value; setting a hysteresis range on a power instruction of an energy storage system, and when a power demand of the power grid exceeds an upper limit threshold value of the hysteresis range, switching the energy storage system from a charging mode to a discharging mode; and when the power demand of the power grid is lower than a lower limit threshold value of the hysteresis range, switching the energy storage system from the discharging mode to the charging mode. In the present invention, when the frequency of the power grid is increased, generated power is reduced until power is absorbed from the power grid, and when the frequency of the power grid is reduced, the absorption of power from the power grid is reduced until electrical power is delivered to the power grid, thus achieving full-range participation of energy storage in power grid frequency regulation control, and satisfying regulation requirements of power grids.

Description

A method and system for energy storage charging and discharging to fully participate in grid frequency regulation Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a method and system for energy storage charging and discharging to fully participate in grid frequency modulation. Background Art

[0002] Energy storage systems are a crucial component of power systems, primarily used to store excess electricity and release it when needed. In power grids, energy storage systems typically operate in separate phases: the storage phase and the release phase. During the storage phase, when grid power supply exceeds demand, the energy storage system stores the excess energy. During the release phase, when grid power demand exceeds supply, the energy storage system releases the stored energy to meet grid demand.

[0003] In the power system, frequency stability is one of the key indicators for stable system operation. The frequency of the power grid needs to be maintained within a certain range. For example, in China, the standard frequency of the power grid is 50Hz, and the allowable deviation range is usually ±0.2Hz. In order to maintain frequency stability, power grid operators will implement frequency regulation services, including primary frequency regulation, secondary frequency regulation, and tertiary frequency regulation. As a flexible regulation resource, the energy storage system can respond to the frequency regulation needs of the power grid by storing and releasing energy. However, traditional energy storage systems separate the energy storage (charging) stage and the energy release (discharging) stage, and only participate in the power grid frequency regulation control during the energy release (discharging) stage, resulting in a small load regulation amplitude and insufficient support for the power grid. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: how to simultaneously enable the energy storage charging system and the power generation system to participate in the grid frequency regulation control operation, and by constructing a full-range adjustment coefficient and charging and discharging operation mode, realize the full-range power regulation of the energy storage system to respond to grid frequency changes.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for fully participating in grid frequency regulation of energy storage charging and discharging, comprising:

[0007] Collect power and frequency data of power grid operation and build full range regulation coefficient;

[0008] Set the upper and lower limits of the frequency dead zone, obtain the adjusted power value according to the real-time frequency range, and calculate the theoretical power command value;

[0009] The actual output power command value is obtained based on the constraint function constructed according to the theoretical power command value and the charging and generating power rating, and the grid operation is controlled according to the actual output power command value;

[0010] A hysteresis interval is set on the power command of the energy storage system. When the power demand of the grid exceeds the upper threshold of the hysteresis interval, the energy storage system switches from charging mode to discharging mode; when the power demand of the grid falls below the lower threshold of the hysteresis interval, the energy storage system switches from discharging mode to charging mode.

[0011] As a preferred embodiment of the method for full-range participation of energy storage charging and discharging in grid frequency regulation according to the present invention, the construction of the full-range regulation coefficient includes collecting the upper and lower frequency limits of the grid operation, recording the generator power rating and the motor charging power rating, and calculating the full-range regulation coefficient. The formula is expressed as follows:

[0012] Where ε represents the full range adjustment coefficient; P g Indicates the rated power of power generation; P s Indicates the charging power rating; f u Indicates the upper frequency limit; f d Indicates the lower limit of frequency; f indicates the current grid frequency; f ε Indicates that the frequency deviates from the rated frequency; represents the adjustment sensitivity; α represents the parameter that adjusts the growth rate of the exponential function; represents the normalized function, simulating the nonlinear characteristics of charging power changing with frequency; f n represents the frequency value of the nth segment; β represents the parameter for adjusting the steepness of the curve.

[0013] As a preferred solution of the method for full-range participation of energy storage charging and discharging in grid frequency regulation described in the present invention, the power adjustment includes using the real-time grid frequency value and the rated grid frequency value to construct an adjustment power value function with the constraints of the upper and lower limits of the frequency dead zone, which is expressed as follows:

[0014] Where ΔP represents the adjusted power value; f r Indicates the real-time value of frequency; f0 indicates the rated value of frequency; Δ u Indicates the upper limit of the frequency dead zone; Δ d Indicates the lower limit of the frequency dead zone;

[0015] When the ΔP value is positive, the power is increased, and when the ΔP value is negative, the power is decreased.

[0016] As a preferred solution of the method for full-range participation of energy storage charging and discharging in grid frequency regulation described in the present invention, the actual output power command value includes obtaining the actual output power command value based on a constraint function constructed according to a theoretical power command value and a charging and generating power rating, and controlling grid operation according to the actual output power command value;

[0017] The formula for calculating the theoretical power command value is expressed as: P c =ΔP+P r

[0018] Among them, P c Indicates the theoretical power command value; P r Indicates the real-time value of power;

[0019] Make a judgment and get the actual output power command value, the formula is expressed as:

[0020] Among them, P c ' represents the actual output power command value; P c 'The value is when the energy storage system enters the discharge state and the system outputs power P c ';P c 'When the value is negative, the energy storage system enters the charging state, and the system consumes external power |P c' |.

[0021] As a preferred solution of the method for full-range participation of energy storage charging and discharging in grid frequency regulation described in the present invention, the upper and lower frequency limits are pre-set according to the design standards and stable operation requirements of the grid; the specific method is to determine the standard operating frequency of the grid according to the preset regional standards; calculate the tolerable frequency deviation range of the grid, and set the upper and lower frequency limits accordingly;

[0022] The formula for the upper limit of grid frequency is expressed as:

[0023] The formula for the lower limit of grid frequency is expressed as:

[0024] Among them, f0 represents the standard operating frequency of the power grid determined by the preset regional standard; Δf represents the basic frequency deviation range; Λ and a n The coefficients of the Fourier series are used to simulate the periodic adjustment of the grid frequency due to seasonal load changes; t represents the current time when the operating frequency is measured; T represents the cycle length; φ n Indicates phase shift, simulating the effect of seasonal changes; L indicates real-time load; L crepresents the load critical value; C represents the contribution ratio of renewable energy in the current power grid; Γ(f0,L,C) represents the chaotic mapping function, which reflects the combined impact of grid load and renewable energy contribution on frequency regulation;

[0025] The chaotic mapping function Γ is expressed as:

[0026] Among them, L max Indicates the maximum load the power grid can bear.

[0027] As a preferred solution of the method for full-range participation of energy storage charging and discharging in grid frequency regulation described in the present invention, the hysteresis interval includes, further comprising setting a hysteresis interval on the power command of the energy storage system, the hysteresis interval defining the range in which the energy storage system does not respond to slight changes in grid power demand when switching between charging and discharging states, thereby avoiding frequent charging and discharging switching.

[0028] The hysteresis interval threshold is pre-set based on the normal operating conditions of the power grid and the performance characteristics of the energy storage system. The hysteresis interval is defined by setting two power thresholds: an upper hysteresis interval threshold for discharge and a lower hysteresis interval threshold for charge.

[0029] The upper threshold value of the hysteresis interval of discharge is expressed as follows:

[0030] The formula for the lower threshold of the hysteresis interval of charging is expressed as:

[0031] Among them, P b represents the power reference value of the energy storage system when no adjustment is required; δ represents the power adjustment sensitivity coefficient set according to the change of grid demand; sin(w·t0+φ) represents the periodic change factor, where w represents the angular frequency, t0 represents the current time, and φ represents the phase difference, simulating the periodic grid load change; k represents the adjustment coefficient of the nonlinear response; P represents the current power demand; P cr Indicates the critical power demand that triggers a power regulation response;

[0032] Among them, when the grid power demand exceeds the upper threshold of the hysteresis interval, the energy storage system switches from charging mode to discharging mode; when the grid power demand is lower than the lower threshold of the hysteresis interval, the energy storage system switches from discharging mode to charging mode.

[0033] As a preferred solution of the method for full-range participation of energy storage charging and discharging in grid frequency regulation described in the present invention, the energy storage system maintains the current charging and discharging state within the hysteresis interval and does not respond to slight fluctuations in grid power demand;

[0034] When the power demand changes outside the hysteresis range, the energy storage system smoothly switches the charging and discharging states at a predetermined rate to avoid impacting the power grid.

[0035] A system for fully participating in grid frequency regulation in which energy storage charging and discharging fully participates in grid frequency regulation, wherein:

[0036] Data acquisition module: responsible for collecting data from real-time grid monitoring equipment, including grid frequency and the current power status of the energy storage system. The data will be transmitted to the data processing and analysis module in real time;

[0037] Data Processing and Analysis Module: This module processes and analyzes the collected data. This module calculates the full-range regulation coefficient in real time and determines whether the energy storage system needs to adjust its power output in response to changes in grid frequency. It also calculates the theoretical power command value for the energy storage system under given conditions.

[0038] Control unit module: Based on the information provided by the data processing and analysis module, it determines the optimal charging and discharging strategy, including how to smoothly switch the charging and discharging states of the energy storage system. The control strategy will take into account the actual needs of the power grid, the performance limitations of the energy storage system, and the requirements for grid stability.

[0039] Energy storage and power generation module: Based on the instructions of the control strategy module, the execution module is responsible for adjusting the actual charging and discharging status of the energy storage system; this includes adjusting the output power of the inverter connected to the grid and managing the energy flow within the energy storage system.

[0040] A computer device comprises: a memory and a processor; the memory stores a computer program, wherein: when the processor executes the computer program, the steps of any one of the methods of the present invention are implemented.

[0041] A computer-readable storage medium stores a computer program thereon, comprising: steps of implementing any one of the methods of the present invention when the computer program is executed by a processor.

[0042] The beneficial effects of this invention include enabling the energy storage charging system and power generation system to simultaneously participate in grid frequency regulation operations, establishing a full-range differential coefficient. By adjusting the system's operating mode, the system achieves full-range power variation in charge and discharge, responding to grid frequency fluctuations. When the grid frequency rises, the generated power is reduced until power is absorbed from the grid; when the grid frequency drops, the power absorbed from the grid is reduced until power is delivered to the grid. This allows energy storage to fully participate in grid frequency regulation, meeting grid regulation requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0044] FIG1 is an overall flow chart of a method for fully participating in grid frequency regulation of energy storage charging and discharging provided by a first embodiment of the present invention;

[0045] FIG2 is a flow chart of a charge-discharge switching method for a method in which energy storage charge and discharge fully participate in grid frequency modulation, provided by a first embodiment of the present invention;

[0046] FIG3 is a diagram of an energy storage charging and discharging regulation system for a method in which energy storage charging and discharging fully participates in grid frequency regulation, provided by the first embodiment of the present invention. DETAILED DESCRIPTION

[0047] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0048] Example 1

[0049] 1-3 , an embodiment of the present invention provides a method for fully participating in grid frequency regulation with energy storage charging and discharging, including:

[0050] S1: Collect power and frequency data of power grid operation and construct full range regulation coefficient.

[0051] Furthermore, the collection of grid operation power and frequency data includes:

[0052] Furthermore, the construction of the full-range regulation coefficient includes collecting the upper and lower frequency limits of the power grid operation, recording the generator power rating and the motor charging power rating, and calculating the full-range regulation coefficient. The formula is expressed as follows:

[0053] Where ε represents the full range adjustment coefficient; P g Indicates the rated power of power generation; P s Indicates the charging power rating; f u Indicates the upper frequency limit; f d Indicates the lower limit of frequency; f indicates the current grid frequency; f ε Indicates that the frequency deviates from the rated frequency; represents the adjustment sensitivity; α represents the parameter that adjusts the growth rate of the exponential function; represents the normalized function, simulating the nonlinear characteristics of charging power changing with frequency; f n represents the frequency value of the nth segment; β represents the parameter for adjusting the steepness of the curve.

[0054] Going a step further, a full-range regulation coefficient is constructed. This step centers on calculating a full-range regulation coefficient based on the grid's real-time demands and predetermined operating parameters (such as upper and lower frequency limits and generator and motor power ratings). This coefficient reflects how the energy storage system should adjust its charging and discharging behavior to maintain grid frequency stability under current grid conditions. The innovation of this coefficient lies in its unified consideration of the energy storage system's charging and discharging processes, allowing the system to flexibly respond to changes in grid demand across the full power range.

[0055] It should be noted that collecting grid operating power and frequency data is fundamental to achieving precise frequency regulation. Real-time monitoring of the grid's operating status provides timely and accurate understanding of current grid demand, providing direct data support for energy storage system regulation. Based on the calculated full-range regulation coefficient, the energy storage system can rapidly adjust its output power when the grid frequency exceeds the normal operating range, either increasing discharge or decreasing charging, in a smooth and responsive manner. This adjustment mechanism not only improves grid stability but also enhances its adaptability to emergencies.

[0056] S2: Set the upper and lower limits of the frequency dead zone, obtain the adjusted power value according to the real-time frequency range, and calculate the theoretical power command value.

[0057] Furthermore, the power value adjustment includes using the real-time value of the grid frequency and the rated value of the grid frequency to construct an adjustment power value function whose constraints are the upper and lower limits of the frequency dead zone, and the formula is expressed as follows:

[0058] Where ΔP represents the adjusted power value; f r Indicates the real-time value of frequency; f0 indicates the rated value of frequency; Δ u Indicates the upper limit of the frequency dead zone; Δ d Indicates the lower limit of the frequency dead zone.

[0059] Furthermore, the power is increased when the ΔP value is positive, and the power is decreased when the ΔP value is negative.

[0060] Furthermore, the actual output power command value includes obtaining the actual output power command value according to a constraint function constructed based on the theoretical power command value and the charging and generating power rating, and controlling the operation of the power grid according to the actual output power command value.

[0061] Furthermore, the formula for calculating the theoretical power command value is expressed as: P c =ΔP+P r

[0062] Among them, P c Indicates the theoretical power command value; P r Indicates the real-time power value.

[0063] Furthermore, a judgment is made to obtain the actual output power command value, which is expressed as follows:

[0064] Among them, P c ' represents the actual output power command value; P c 'The value is when the energy storage system enters the discharge state and the system outputs power P c ';P c 'When the value is negative, the energy storage system enters the charging state, and the system consumes external power |P c' |.

[0065] It should be noted that setting a frequency deadband constraint: This step defines a tolerable frequency deviation range (deadband) to avoid frequent state switching of the energy storage system due to small fluctuations in the grid frequency, thereby reducing system wear and operating costs. Constructing an adjustment power value function: By analyzing the difference between the real-time grid frequency and the rated frequency and considering the frequency deadband constraint, the power value that needs to be adjusted for the energy storage system is accurately calculated. The innovation of this step lies in the ability to dynamically adjust the output of the energy storage system in response to real-time changes in the grid frequency, thereby improving the response speed and stability of the grid.

[0066] S3: Obtain the actual output power command value based on the constraint function constructed according to the theoretical power command value and the charging and generating power rating, and control the grid operation according to the actual output power command value.

[0067] Furthermore, the upper and lower frequency limits are pre-set according to the design standards of the power grid and the requirements for stable operation; the specific method is to determine the standard operating frequency of the power grid according to the preset regional standards; calculate the tolerable frequency deviation range of the power grid, and set the upper and lower frequency limits accordingly.

[0068] Furthermore, the formula for the upper limit of the grid frequency is expressed as:

[0069] Furthermore, the formula for the lower limit of the grid frequency is expressed as:

[0070] Among them, f0 represents the standard operating frequency of the power grid determined by the preset regional standard; Δf represents the basic frequency deviation range; Λ and a nThe coefficients of the Fourier series are used to simulate the periodic adjustment of the grid frequency due to seasonal load changes; t represents the current time when the operating frequency is measured; T represents the cycle length; φ n Indicates phase shift, simulating the effect of seasonal changes; L indicates real-time load; L c represents the load critical value; C represents the contribution ratio of renewable energy in the current power grid; Γ(f0,L,C) represents the chaotic mapping function, which reflects the comprehensive impact of grid load and renewable energy contribution on frequency adjustment.

[0071] Furthermore, the chaotic mapping function Γ is expressed as:

[0072] Among them, L max Indicates the maximum load the power grid can bear.

[0073] It should be noted that the calculation of theoretical and actual output power command values ​​not only calculates the energy storage system's ideal power output but also derives an executable power command value based on the system's actual performance and limitations. This strategy ensures that the energy storage system can maximize its support for grid frequency regulation while protecting its own safety and extending its lifespan.

[0074] S4: A hysteresis interval is set on the power command of the energy storage system. When the power demand of the grid exceeds the upper threshold of the hysteresis interval, the energy storage system switches from charging mode to discharging mode; when the power demand of the grid is lower than the lower threshold of the hysteresis interval, the energy storage system switches from discharging mode to charging mode.

[0075] Furthermore, the hysteresis interval includes setting a hysteresis interval on the power instruction of the energy storage system, which defines the range in which the energy storage system does not respond to slight changes in the power demand of the power grid when switching the charge and discharge states, thereby avoiding frequent charge and discharge switching.

[0076] Furthermore, the threshold of the hysteresis interval is pre-set based on the normal operating conditions of the power grid and the performance characteristics of the energy storage system. The hysteresis interval is defined by setting two power thresholds, namely an upper threshold of the hysteresis interval for discharging and a lower threshold of the hysteresis interval for charging.

[0077] Furthermore, the upper threshold value of the hysteresis interval of discharge is expressed as follows:

[0078] Furthermore, the formula for the lower threshold of the hysteresis interval of charging is expressed as:

[0079] Among them, P brepresents the power reference value of the energy storage system when no adjustment is required; δ represents the power adjustment sensitivity coefficient set according to the change of grid demand; sin(w·t0+φ) represents the periodic change factor, where w represents the angular frequency, t0 represents the current time, and φ represents the phase difference, simulating the periodic grid load change; k represents the adjustment coefficient of the nonlinear response; P represents the current power demand; P cr Indicates the critical power demand that triggers a power regulation response.

[0080] Furthermore, when the grid power demand exceeds the upper limit threshold of the hysteresis interval, the energy storage system switches from charging mode to discharging mode; when the grid power demand is lower than the lower limit threshold of the hysteresis interval, the energy storage system switches from discharging mode to charging mode.

[0081] Furthermore, the energy storage system maintains its current charge and discharge state within the hysteresis interval, refraining from responding to minor fluctuations in grid power demand. When power demand changes outside the hysteresis interval, the energy storage system smoothly switches charge and discharge states at a predetermined rate to avoid impacting the grid.

[0082] It should be noted that the smooth switching of charge and discharge states: the innovative use of a predetermined rate to smoothly switch the charge and discharge states of the energy storage system significantly reduces the impact of the operation of the energy storage system on the stability of the power grid. This smooth switching mechanism ensures that the power grid can obtain continuous and stable support when facing large-scale changes in power demand, thereby improving the reliability and resilience of the power grid. Optimizing the power grid frequency regulation service: The present invention provides the power grid with a more flexible and efficient frequency regulation service by precisely controlling the power output of the energy storage system. While maintaining the stability of the power grid frequency, the energy storage system can also meet the real-time needs of the power grid.

[0083] On the other hand, this embodiment also provides a system for fully participating in grid frequency regulation of energy storage charging and discharging, which includes:

[0084] Data acquisition module: Responsible for collecting data from real-time grid monitoring equipment, including grid frequency and the current power status of the energy storage system. The data will be transmitted to the data processing and analysis module in real time.

[0085] Data Processing and Analysis Module: This module processes and analyzes the collected data. This module calculates the full-range regulation coefficient in real time and determines whether the energy storage system needs to adjust its power output in response to changes in grid frequency. It also calculates the energy storage system's theoretical power command value under given conditions.

[0086] Control unit module: Based on the information provided by the data processing and analysis module, it determines the optimal charging and discharging strategy, including how to smoothly switch the charging and discharging states of the energy storage system. The control strategy will take into account the actual needs of the power grid, the performance limitations of the energy storage system, and the requirements for grid stability.

[0087] Energy storage and power generation module: Based on the instructions of the control strategy module, the execution module is responsible for adjusting the actual charging and discharging status of the energy storage system; this includes adjusting the output power of the inverter connected to the grid and managing the energy flow within the energy storage system.

[0088] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0089] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0090] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0091] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0092] Example 2

[0093] The following is an embodiment of the present invention, which provides a method for energy storage charging and discharging to participate in grid frequency regulation in the full range. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0094] The rated power of a certain energy storage system P g The charging power rating is 15MW. s =10MW, which is expressed as -10MW in the formula. According to GB / T15945-1995 "Permissible Deviation of Power System Frequency for Power Quality", the permissible deviation of the grid frequency is ±0.2Hz. The normal frequency f0 of the grid is 50Hz, so the corresponding frequency upper limit f u is 50.2Hz, the lower limit of frequency f d is 49.8Hz. At this time, the full-range adjustment coefficient ε can be calculated to be 62.5.

[0095] Frequency dead zone usually refers to the frequency difference set in the power system to prevent unnecessary system action when the grid frequency changes within a small range. Taking a thermal power unit as an example, the corresponding primary frequency dead zone is 0.033Hz, and the corresponding frequency dead zone upper limit Δ u is 50.033, the lower limit of the frequency dead zone Δ d As a flexible regulation resource, the energy storage system can respond to the frequency regulation needs of the power grid by storing and releasing energy. It is necessary to calculate the actual output power command P c '. Assume that the real-time power value P r It is 12MW.

[0096] (1) When the theoretical power command value P c When it is 20MW, it is greater than the rated power value P g , actual output power command P c 'Equal to the rated power P g :P c '=P g=15MW, at this time, the energy storage system enters the discharge state, and the system outputs 15MW of power to the outside;

[0097] (2) When the theoretical power command value P c When it is 13MW, it is between the rated power value P g And charging power rating P s At this time, it is necessary to adjust the real-time frequency f r Calculate the adjusted power value ΔP.

[0098] ①. When the real-time frequency value f r When it is 50.1Hz, it exceeds the upper limit of the frequency dead zone Δ u , calculate the adjusted power value ΔP as: Actual output power command P c 'Equal to the adjusted power value ΔP plus the real-time power value P r For: P c '=1.875+12=13.875MW. At this time, the energy storage system enters the discharge state and the system outputs 13.875MW of power.

[0099] ②. When the real-time frequency value f r When the frequency is 50.01Hz, it is between the upper and lower limits of the frequency dead zone. The power adjustment value ΔP is calculated as: ΔP = 0. The actual output power command P c 'Equal to the adjusted power value ΔP plus the real-time power value P r For: P c '=0+12=12MW;

[0100] ③. When the real-time frequency value f r When it is 49.9Hz, it is less than the lower limit of the frequency dead zone Δ d , calculate the adjusted power value ΔP as: Actual output power command P c 'Equal to the adjusted power value ΔP plus the real-time power value P r For: P c ' = -1.25 + 12 = 10.75MW. At this time, the energy storage system enters the discharge state and the system outputs 10.75MW of power.

[0101] (3) When the theoretical power command value P c When it is -12MW, it is less than the charging power rating P s , then the actual output power instruction P c 'Equal to the charging power rating P s :P c '=-10MW, at this time, the energy storage system enters the charging state, and the system consumes 10MW of external power.

[0102] 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 the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for fully participating in grid frequency modulation with energy storage charging and discharging, characterized in that: include: Collect power and frequency data of power grid operation and build full range regulation coefficient; Set the upper and lower limits of the frequency dead zone, obtain the adjusted power value according to the real-time frequency range, and calculate the theoretical power command value; The actual output power command value is obtained based on the constraint function constructed according to the theoretical power command value and the charging and generating power rating, and the grid operation is controlled according to the actual output power command value; A hysteresis interval is set on the power command of the energy storage system. When the power demand of the grid exceeds the upper threshold of the hysteresis interval, the energy storage system switches from charging mode to discharging mode; when the power demand of the grid falls below the lower threshold of the hysteresis interval, the energy storage system switches from discharging mode to charging mode.

2. The method for full-range participation of energy storage charging and discharging in grid frequency modulation according to claim 1, characterized in that: The full-range regulation coefficient is constructed by collecting the upper and lower frequency limits of the power grid, recording the rated power of the generator and the rated power of the motor, and calculating the full-range regulation coefficient. The formula is: Where ε represents the full range adjustment coefficient; P g Indicates the rated power of power generation; P s Indicates the charging power rating; f u Indicates the upper frequency limit; f d Indicates the lower limit of frequency; f indicates the current grid frequency; f ε Indicates that the frequency deviates from the rated frequency; represents the adjustment sensitivity; α represents the parameter that adjusts the growth rate of the exponential function; represents the normalized function, simulating the nonlinear characteristics of charging power changing with frequency; f n represents the frequency value of the nth segment; β represents the parameter for adjusting the steepness of the curve.

3. The method for full-range participation of energy storage charging and discharging in grid frequency modulation according to claim 2, characterized in that: The power value adjustment includes using the real-time value of the grid frequency and the rated value of the grid frequency to construct an adjustment power value function with the constraints of the upper and lower limits of the frequency dead zone, which is expressed as follows: Where ΔP represents the adjusted power value; f r Indicates the real-time value of frequency; f0 indicates the rated value of frequency; Δ u Indicates the upper limit of the frequency dead zone; Δ d Indicates the lower limit of the frequency dead zone; When the ΔP value is positive, the power is increased, and when the ΔP value is negative, the power is decreased.

4. The method for fully participating in grid frequency modulation with energy storage charging and discharging according to claim 3, characterized in that: The actual output power command value includes obtaining the actual output power command value based on a constraint function constructed according to the theoretical power command value and the charging and generating power rating, and controlling the operation of the power grid according to the actual output power command value; The formula for calculating the theoretical power command value is expressed as: P c =ΔP+P r Among them, P c Indicates the theoretical power command value; P r Indicates the real-time value of power; Make a judgment and get the actual output power command value, the formula is expressed as: Among them, P c ' represents the actual output power command value; P c 'The value is when the energy storage system enters the discharge state and the system outputs power P c ';P c 'When the value is negative, the energy storage system enters the charging state, and the system consumes external power |P c' |.

5. The method for full-range participation of energy storage charging and discharging in grid frequency modulation according to claim 4, characterized in that: The upper and lower frequency limits are pre-set according to the design standards of the power grid and the requirements for stable operation; The specific method is to determine the standard operating frequency of the power grid according to the preset regional standards; calculate the tolerable frequency deviation range of the power grid and set the upper and lower frequency limits accordingly; The formula for the upper limit of grid frequency is expressed as: The formula for the lower limit of grid frequency is expressed as: Among them, f0 represents the standard operating frequency of the power grid determined by the preset regional standard; Δf represents the basic frequency deviation range; Λ and a n The coefficients of the Fourier series are used to simulate the periodic adjustment of the grid frequency due to seasonal load changes; t represents the current time when the operating frequency is measured; T represents the cycle length; φ n Indicates phase shift, simulating the effect of seasonal changes; L indicates real-time load; L c represents the load critical value; C represents the contribution ratio of renewable energy in the current power grid; Γ(f0,L,C) represents the chaotic mapping function, which reflects the combined impact of grid load and renewable energy contribution on frequency regulation; The chaotic mapping function Γ is expressed as: Among them, L max Indicates the maximum load the power grid can bear.

6. The method for fully participating in grid frequency modulation by energy storage charging and discharging according to claim 5, characterized in that: The hysteresis interval includes, further including setting a hysteresis interval on the power instruction of the energy storage system, which defines the range in which the energy storage system does not respond to slight changes in the power demand of the power grid when switching the charge and discharge states, thereby avoiding frequent charge and discharge switching. The hysteresis interval threshold is pre-set based on the normal operating conditions of the power grid and the performance characteristics of the energy storage system. The hysteresis interval is defined by setting two power thresholds: an upper hysteresis interval threshold for discharge and a lower hysteresis interval threshold for charge. The upper threshold value of the hysteresis interval of discharge is expressed as follows: The formula for the lower threshold of the hysteresis interval of charging is expressed as: Among them, P b represents the power reference value of the energy storage system when no adjustment is required; δ represents the power adjustment sensitivity coefficient set according to the change of grid demand; sin(w·t0+φ) represents the periodic change factor, where w represents the angular frequency, t0 represents the current time, and φ represents the phase difference, simulating the periodic grid load change; k represents the adjustment coefficient of the nonlinear response; P represents the current power demand; P cr Indicates the critical power demand that triggers a power regulation response; Among them, when the grid power demand exceeds the upper threshold of the hysteresis interval, the energy storage system switches from charging mode to discharging mode; when the grid power demand is lower than the lower threshold of the hysteresis interval, the energy storage system switches from discharging mode to charging mode.

7. The method for fully participating in grid frequency modulation with energy storage charging and discharging according to claim 6, characterized in that: The energy storage system maintains its current charge and discharge state within the hysteresis interval and does not respond to slight fluctuations in grid power demand; When the power demand changes outside the hysteresis range, the energy storage system smoothly switches the charging and discharging states at a predetermined rate to avoid impacting the power grid.

8. A system for fully participating in grid frequency modulation using a method according to any one of claims 1 to 7, characterized in that: Data acquisition module: responsible for collecting data from real-time grid monitoring equipment, including grid frequency and the current power status of the energy storage system. The data will be transmitted to the data processing and analysis module in real time; Data processing and analysis module: This module processes and analyzes the collected data. This module calculates the full-range regulation coefficient in real time and determines whether the energy storage system needs to adjust its power output in response to changes in grid frequency. This module also calculates the theoretical power command value of the energy storage system under given conditions. Control unit module: Based on the information provided by the data processing and analysis module, it determines the optimal charging and discharging strategy, including how to smoothly switch the charging and discharging states of the energy storage system. The control strategy will take into account the actual needs of the power grid, the performance limitations of the energy storage system, and the requirements for grid stability. Energy storage and power generation module: Based on the instructions of the control strategy module, the execution module is responsible for adjusting the actual charging and discharging status of the energy storage system; this includes adjusting the output power of the inverter connected to the grid and managing the energy flow within the energy storage system.

9. A computer device comprising: memory and processor; The memory stores a computer program, which is characterized in that when the processor executes the computer program, the steps of the method for energy storage charging and discharging to participate in power grid frequency regulation in a full range are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for implementing a full range of energy storage charging and discharging to participate in grid frequency regulation are implemented.

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