Energy storage frequency modulation method and system for optimizing control parameters

Abstract

The invention discloses an energy storage frequency modulation method and system for optimizing control parameters, and relates to the technical field of energy storage system application, and the method comprises the steps: setting a frequency modulation dead zone, and monitoring the frequency in real time; when frequency fluctuation exceeds a frequency modulation dead zone, disturbance estimation is carried out, related parameters are calculated, and a frequency safety trajectory planning constraint is constructed in combination with a first frequency critical index; if the frequency fluctuation exceeds a first threshold value, performing rapid power control to enable the frequency change trajectory to return to the frequency safety trajectory planning constraint, otherwise, judging the frequency variation; and if the frequency variation does not exceed a second threshold value, keeping a predetermined droop parameter for control, otherwise, adopting a variable droop parameter for control until the system frequency change returns to the frequency safety trajectory planning constraint and the control is ended when a new steady state is entered. The defect that a traditional generator set is slow in response and cannot provide fast and sufficient frequency modulation power is overcome, and the frequency modulation range and frequency modulation efficiency of the power generation side are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage system applications, and in particular to an energy storage frequency modulation method and system for optimizing control parameters. Background Art

[0002] With the rapid development of the economy and society, the demand for electricity is growing, resulting in obvious seasonal and time-specific characteristics of electricity load. This rapid growth in load has led to an increase in the volatility of grid frequency, posing a challenge to the stability of the power system. Traditional thermal power generating units are often unable to quickly respond to grid frequency fluctuations caused by load mutations or failures due to their mechanical inertia and response speed limitations. In addition, with the increasing proportion of renewable energy, the intermittent and uncertain nature of wind and solar power generation has further increased the difficulty of grid frequency control.

[0003] In this context, using energy storage systems to assist grid frequency regulation has become an effective solution. Due to its rapid response capability and bidirectional energy flow characteristics, energy storage systems can provide or absorb a large amount of electrical energy in a short period of time, thereby quickly compensating for power imbalances in the grid and slowing down frequency fluctuations. In particular, when the grid frequency is abnormal, the energy storage system can immediately intervene to provide the necessary power support to prevent the frequency from further deteriorating until conventional power generation units or other regulation resources intervene.

[0004] However, the capacity of current energy storage systems is relatively limited, and their frequent charging and discharging will affect the life of the equipment. Therefore, how to reasonably allocate the frequency regulation tasks of the energy storage system while ensuring the safe and stable operation of the power grid frequency, and avoid excessive use that causes equipment damage or shortened service life, has become an urgent problem to be solved. In addition, the control strategies for energy storage systems in the prior art are mostly fixed parameter settings, lacking the ability to dynamically adjust according to the real-time power grid status, resulting in the inability to fully utilize the frequency regulation potential of the energy storage system in some cases. Therefore, it is of great practical significance to develop an energy storage frequency regulation strategy that optimizes control parameters to achieve a frequency regulation strategy that balances frequency stability and efficient utilization of energy storage resources. Summary of the invention

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention aims at the defect of slow frequency regulation reaction speed of traditional units, makes full use of the advantage of rapid energy storage output, and proposes an energy storage frequency regulation method with optimized control parameters. The main core idea is: disturbance estimation is performed according to the frequency drop or rise curve, and then the frequency change rate and frequency change amount are used as conditions, respectively, combined with the critical indicators actually required by the power grid to change the system control parameters so that the frequency change curve returns to the planned safe trajectory range, which accordingly determines the degree of energy storage output.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a method for energy storage frequency regulation with optimized control parameters, comprising: setting a frequency regulation dead zone and monitoring the frequency in real time; when the frequency fluctuation exceeds the frequency regulation dead zone, performing disturbance estimation and calculating relevant parameters; based on the relevant parameters, a frequency safety trajectory planning constraint is constructed in combination with a first frequency critical indicator; if the frequency fluctuation exceeds a first threshold, rapid power control is performed to bring the frequency change trajectory back within the frequency safety trajectory planning constraint, otherwise the frequency change amount is judged; if the frequency change amount does not exceed a second threshold, a predetermined droop parameter is maintained for control, otherwise a variable droop parameter is used for control until the system frequency changes back within the frequency safety trajectory planning constraint and the control ends when a new steady state is entered.

[0009] As a preferred solution of the energy storage frequency modulation method for optimizing control parameters described in the present invention, the disturbance estimation when the frequency fluctuation exceeds the frequency modulation dead zone includes:

[0010] When the frequency fluctuation exceeds the FM dead zone f N ±f0, record the frequency and frequency change rate at the initial disturbance time t1, and record the frequency and frequency change rate at t2 after the first time interval, and then the energy storage power station excitation small signal P E , after a delay of a second time interval, recording the frequency and the frequency change rate at time t3, wherein the range setting of the frequency modulation dead zone is affected by the normal frequency fluctuation required by the power load;

[0011] Substitute the recorded frequencies and frequency change rates at time t1, t2, and t3 into the system frequency change equation for disturbance prediction. The formula is expressed as follows:

[0012]

[0013] Where H0 represents the system inertia, f represents the system frequency, K L Indicates load unit regulation power, f N Indicates the grid frequency, ΔP L Indicates the size of the disturbance.

[0014] As a preferred solution of the energy storage frequency modulation method for optimizing control parameters described in the present invention, it includes:

[0015] Perform conditional judgment on the frequency change rate at the initial stage of disturbance occurrence according to the first threshold;

[0016] If the frequency change rate at the initial stage of the disturbance exceeds the first threshold, fast power control is performed, and the droop control parameter K is P Change to KPm ;

[0017] Directly output power P through the energy storage power station C To quickly offset the impact of the disturbance on the system, that is, the energy storage output directly changes the frequency change rate and the final value of the frequency change at the initial stage of the disturbance, so that the frequency change trajectory returns to the frequency safety trajectory planning constraint;

[0018] When the frequency change trajectory returns to the frequency safety trajectory planning constraint, the droop control parameter K Pm Then switch back to K P , continue to use droop control.

[0019] As a preferred solution of the energy storage frequency modulation method for optimizing control parameters described in the present invention, it includes:

[0020] If the frequency change rate at the initial stage of the disturbance does not exceed the first threshold, determining the frequency change amount;

[0021] If the frequency change does not exceed the second threshold, the predetermined droop control parameter K is maintained. P Control is performed, wherein the predetermined droop control parameter K P The second threshold is set according to the actual energy storage output planning requirements, and in principle does not exceed the frequency change threshold set according to the power grid requirements;

[0022] If the frequency variation exceeds the second threshold, variable droop parameter control is adopted, and the droop control parameter K is set to P Change to K P1 , until the system frequency changes back to the frequency safety trajectory planning constraint. After the system frequency changes back to the frequency safety trajectory planning constraint, K P1 Return to the droop control parameter K P , the control ends when entering a new steady state.

[0023] As a preferred solution of the energy storage frequency modulation method for optimizing control parameters described in the present invention, when the frequency change rate exceeds the first threshold at the initial stage of the disturbance, rapid power control is performed, and the droop control parameter K PC and energy storage output P C The calculation is:

[0024] P C =|ΔP L |-R m H0

[0025]

[0026] Among them, R mrepresents the first threshold, F m Indicates the frequency change threshold that the power grid requires to be set.

[0027] As a preferred solution of the energy storage frequency modulation method for optimizing control parameters described in the present invention, the calculation-related parameters include:

[0028]

[0029] Among them, f1 and R1 represent the frequency and frequency change rate at the initial moment t1 of the disturbance, f2 and R2 represent the frequency and frequency change rate at the moment t2, and f3 and R3 represent the frequency and frequency change rate at the moment t3.

[0030] As a preferred solution of the energy storage frequency modulation method for optimizing control parameters described in the present invention, the frequency safety trajectory planning constraint construction includes:

[0031] Based on the disturbance size ΔP L , system inertia H0, load unit adjustment power K L , Droop control parameter K P , and combined with the first frequency critical index to construct the frequency safety trajectory planning constraint, the frequency safety trajectory range critical curve equation is:

[0032]

[0033] In a second aspect, the present invention provides an energy storage frequency modulation system for optimizing control parameters, comprising:

[0034] Frequency monitoring unit, used to set the frequency modulation dead zone and monitor the frequency in real time;

[0035] A disturbance prediction unit, used for predicting disturbances and calculating relevant parameters when the frequency fluctuation exceeds the frequency modulation dead zone;

[0036] A constraint construction unit, configured to construct a frequency safety trajectory planning constraint based on the relevant parameters and in combination with a first frequency critical indicator;

[0037] A first control unit is used to perform rapid power control to make the frequency change trajectory return to the frequency safety trajectory planning constraint when the frequency fluctuation exceeds a first threshold, otherwise, to judge the frequency change amount;

[0038] The second control unit is used to maintain the predetermined droop parameter control if the frequency change does not exceed the second threshold, otherwise adopt the variable droop parameter control until the system frequency changes back to the frequency safety trajectory planning constraint and the control ends when entering a new steady state.

[0039] In a third aspect, the present invention provides a computing device, comprising:

[0040] Memory and processor;

[0041] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the method are implemented.

[0042] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which implement the steps of the method when executed by a processor.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: ① The energy storage frequency regulation method with optimized control parameters provided by the present invention makes up for the defect that the traditional generator set has a slow response and cannot provide fast and sufficient frequency regulation power, and improves the frequency regulation range and frequency regulation efficiency on the power generation side; ② Compared with the traditional droop control, the present invention can directly increase the additional power to support frequency recovery, can quickly and effectively make corresponding decisions on system disturbances, and continue to use droop control within the safe and stable trajectory of frequency recovery to maximize the saving of frequency regulation resources; ③ Compared with the traditional direct power control, the present invention sets the frequency change rate R m and frequency change f m These two thresholds can be used to plan the frequency safety trajectory under the disturbance, and reasonable decisions on energy storage output can be made through conditional judgment, which can avoid frequent charging and discharging of energy storage, which can not only optimize the efficiency of energy storage output, but also increase the service life of energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0045] Figure 1 This is an overall flow chart of the energy storage frequency modulation method for optimizing control parameters according to an embodiment of the present invention;

[0046] Figure 2 A specific flow chart of an energy storage frequency modulation strategy of an energy storage frequency modulation method for optimizing control parameters according to an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of the grid-connected structure relationship of an energy storage frequency modulation system of an energy storage frequency modulation method for optimizing control parameters according to an embodiment of the present invention;

[0048] Figure 4A schematic diagram of the disturbance prediction principle of the three-point method of the energy storage frequency modulation method for optimizing control parameters according to an embodiment of the present invention;

[0049] Figure 5 A schematic diagram of frequency safety trajectory planning of an energy storage frequency modulation method for optimizing control parameters according to an embodiment of the present invention;

[0050] Figure 6 It is a schematic diagram comparing the frequency characteristics of the system during conventional droop control and optimized parameter control of the energy storage frequency modulation method with optimized control parameters described in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0052] Example 1

[0053] Reference Figure 1 to Figure 5 As an embodiment of the present invention, a method for energy storage frequency regulation with optimized control parameters is provided. First, when the frequency fluctuation exceeds the frequency regulation dead zone, a three-point disturbance prediction is performed. Then, the frequency safety trajectory planning constraints are performed based on the relevant parameters calculated by the disturbance prediction and in combination with the frequency critical indicators required by the power grid. Next, the frequency fluctuation is subjected to a frequency change rate judgment. If the frequency change rate exceeds the critical frequency change rate, rapid power control is performed to bring the frequency change trajectory back to the predetermined safety trajectory. Otherwise, the next step of frequency change amount judgment is performed. At this time, if the frequency change exceeds the threshold, variable droop parameter control is adopted. Otherwise, the predetermined droop parameter control is adopted. Finally, the control ends when the system frequency changes within a safe range and reaches a new steady state. It should be noted that, Figure 3 As shown, the energy storage frequency regulation system is connected in parallel with the traditional generator set on the AC bus through the converter, assisting the traditional unit in frequency regulation, thus making up for the defects of the traditional unit in long response time and slow frequency regulation power output.

[0054] Specifically, Figure 1 and Figure 2 As shown, a method for energy storage frequency regulation with optimized control parameters includes the following steps:

[0055] S100: Set FM dead zone f N ±f0, and monitor the frequency in real time;

[0056] S200: When the frequency fluctuation exceeds the frequency modulation dead zone, the three-point method is used to estimate the disturbance and calculate the relevant parameters, where the relevant parameters are the disturbance size ΔP L , system inertia H0, load unit adjustment power K L ;

[0057] In the embodiments of the present application, Figure 4 The main principle diagram of the three-point method for disturbance estimation is shown. The system monitors the frequency in real time. If a disturbance occurs and exceeds the frequency modulation dead zone threshold, the three-point method is used to estimate the disturbance size ΔP, taking the frequency drop caused by the disturbance as an example. L , system inertia H0 and load unit regulation power K L The specific process is:

[0058] When the frequency fluctuation exceeds the FM dead zone f N ±f0, record the frequency and frequency change rate at the initial disturbance time t1, and record the frequency and frequency change rate at t2 after the first time interval, and then the energy storage power station excitation small signal P E , after a delay of a second time interval, the frequency and the frequency change rate at time t3 are recorded, wherein the range of the frequency modulation dead zone is set subject to the normal frequency fluctuation required by the power load;

[0059] It should be noted that the value range of the first time interval and the second time interval is 0.1 to 0.2 seconds, and this setting helps to ensure the accuracy and real-time performance of the estimation;

[0060] Furthermore, the recorded frequencies and frequency change rates at time t1, time t2, and time t3 are respectively substituted into the system frequency change equation for disturbance estimation, and the formula is expressed as follows:

[0061]

[0062] Where H0 represents the system inertia, f represents the system frequency, K L Indicates load unit regulation power, f N Indicates the grid frequency, ΔP L represents the disturbance size;

[0063] The calculation of relevant parameters includes:

[0064]

[0065] Among them, f1 and R1 represent the frequency and frequency change rate at the initial moment t1 of the disturbance, f2 and R2 represent the frequency and frequency change rate at the moment t2, and f3 and R3 represent the frequency and frequency change rate at the moment t3.

[0066] S300: Constructing a frequency safety trajectory planning constraint based on relevant parameters and a first frequency critical index;

[0067] In the embodiment of the present application, based on the disturbance size ΔP L , system inertia H0, load unit adjustment power K L , Droop control parameter K P , and combined with the first frequency critical index to construct the frequency safety trajectory planning constraint, the frequency safety trajectory range critical curve equation is:

[0068]

[0069] It should be noted that the first frequency critical index is the frequency critical index required by the power grid. The frequency critical index required by the power grid refers to the allowable fluctuation range of the power grid frequency under normal operation, which is usually a standard or specification formulated to ensure the stable operation of the power system;

[0070] In a feasible implementation, the frequency critical indicators required by the power grid may be the maximum allowable frequency deviation, frequency response time, frequency dynamic characteristics, and frequency stability, specifically:

[0071] ① Maximum allowable frequency deviation: refers to the maximum allowable offset of the grid frequency relative to the nominal frequency (such as 50Hz or 60Hz). For example, some grids stipulate that the frequency fluctuation shall not exceed ±0.2Hz or ±0.5Hz to ensure the stability of the power system and the quality of power supply;

[0072] ②Frequency response time: refers to the time required for the grid frequency to return to the permissible range after being disturbed;

[0073] ③Frequency dynamic characteristics: refers to the dynamic change characteristics of the power grid frequency after the disturbance occurs, including indicators such as the rate of change of frequency (ROCOF), because excessive frequency change rate may cause the protection device to operate and even cause a system disconnection accident;

[0074] ④ Frequency stability: In the long run, the grid frequency needs to be maintained at a stable level to ensure that all equipment within the power system can work normally;

[0075] It should be noted that if Figure 5The figure shows a schematic diagram of frequency safety trajectory planning. The purpose of frequency safety trajectory planning is to ensure that the frequency change trend does not deteriorate, fully consider the limited energy storage frequency regulation resources, optimize the energy storage output mode, and ensure frequency safety and stability, while saving frequency regulation resources and avoiding frequent charging and discharging of energy storage systems. When constructing frequency safety trajectory planning constraints, the frequency critical index required by the power grid is to ensure that even after a certain scale of disturbance occurs, the power grid frequency can still be maintained within the allowable range and recover to the nominal value as soon as possible. By reasonably setting relevant parameters and combining the frequency critical index required by the power grid, effective control of frequency fluctuations can be achieved, thereby ensuring the safe and stable operation of the power system.

[0076] S400: setting a first threshold according to the grid requirements to perform conditional judgment on the frequency change rate at the initial stage of the disturbance; if the frequency fluctuation exceeds the first threshold, performing rapid power control to return the frequency change trajectory to within the frequency safety trajectory planning constraint; otherwise, judging the frequency change amount;

[0077] In the embodiment of the present application, the conditional judgment of the frequency change rate at the initial stage of the disturbance is performed according to the first threshold; if the frequency change rate at the initial stage of the disturbance exceeds the first threshold, rapid power control is performed;

[0078] It should be noted that the frequency change rate R at the initial stage of disturbance is calculated as:

[0079]

[0080] Energy storage output P C for:

[0081] P C =|ΔP L |-R m H0

[0082] Among them, R m represents the first threshold value, which is the frequency change rate threshold value required by the power grid;

[0083] At this time, the droop control parameter K P Change to K Pm , then the calculation of the frequency change rate R at the initial stage of the disturbance and the final value F of the frequency change is:

[0084]

[0085] It should be noted that the direct output power P C To quickly offset the impact of disturbances on the system, that is, the energy storage output directly changes the frequency change rate and the final value of the frequency change at the initial stage of the disturbance, so the falling or rising frequency can be gradually pulled back to the safe range, thereby making the frequency change trajectory return to the frequency safety trajectory planning constraint;

[0086] Furthermore, when the frequency change trajectory returns to the frequency safety trajectory planning constraint, the droop control parameter K Pm Then switch back to K P , continue to use droop control;

[0087] It should be noted that K Pm The solution expression is:

[0088]

[0089] S500: setting a second threshold value according to actual requirements. If the frequency change does not exceed the second threshold value, maintaining the predetermined droop parameter for control. Otherwise, using the variable droop parameter for control until the system frequency changes back to the frequency safety trajectory planning constraint and enters a new steady state, and the control ends.

[0090] In the embodiment of the present application, if the frequency change rate does not exceed the first threshold value at the initial stage of the disturbance, the frequency change amount is judged;

[0091] If the frequency change does not exceed the second threshold, the predetermined droop control parameter K is maintained. P Control is performed, wherein the predetermined droop control parameter K P The second threshold value f is set according to the actual energy storage output planning requirements. m The threshold is set according to actual requirements. In principle, it should not exceed the frequency change threshold F set by the power grid. m , F m <50Hz;

[0092] It should be noted that the frequency change final value F and the predetermined droop control parameter K P , load unit adjustment power K L , disturbance size ΔP L The relationship is:

[0093]

[0094] Furthermore, if the frequency variation exceeds the second threshold, variable droop parameter control is adopted, and the droop control parameter K is set to P Change to K P1 , K P1 ≥K P , until the system frequency changes back to the frequency safety trajectory planning constraints. After the system frequency changes back to the frequency safety trajectory planning constraints, K P1 Return to the droop control parameter K P , the control ends when entering a new steady state.

[0095] From the above, it can be seen that ① the energy storage frequency regulation method with optimized control parameters provided by the present invention makes up for the defect that the traditional generator set responds slowly and cannot provide fast and sufficient frequency regulation power, and improves the frequency regulation range and frequency regulation efficiency on the power generation side; ② Compared with the traditional droop control, the present invention can directly increase the additional power to support frequency recovery, can quickly and effectively make corresponding decisions on system disturbances, and continue to use droop control within the safe and stable trajectory of frequency recovery to maximize the saving of frequency regulation resources; ③ Compared with the traditional direct power control, the present invention sets the frequency change rate R m and frequency change f m These two thresholds can be used to plan the frequency safety trajectory under the disturbance, and reasonable decisions on energy storage output can be made through conditional judgment, which can avoid frequent charging and discharging of energy storage, which can not only optimize the efficiency of energy storage output, but also increase the service life of energy storage.

[0096] The above is a schematic scheme of an energy storage frequency modulation method for optimizing control parameters in this embodiment. It should be noted that the technical scheme of the energy storage frequency modulation system for optimizing control parameters and the technical scheme of the energy storage frequency modulation method for optimizing control parameters above belong to the same concept, and the details of the technical scheme of the energy storage frequency modulation system for optimizing control parameters in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the energy storage frequency modulation method for optimizing control parameters above.

[0097] This embodiment also provides an energy storage frequency modulation system for optimizing control parameters, including:

[0098] Frequency monitoring unit, used to set the frequency modulation dead zone and monitor the frequency in real time;

[0099] A disturbance prediction unit is used to predict disturbances and calculate related parameters when the frequency fluctuation exceeds the frequency modulation dead zone;

[0100] A constraint construction unit, used to construct a frequency safety trajectory planning constraint based on relevant parameters and in combination with a first frequency critical indicator;

[0101] A first control unit is used to perform rapid power control to return the frequency change trajectory to the frequency safety trajectory planning constraint when the frequency fluctuation exceeds a first threshold, otherwise, to judge the frequency change amount;

[0102] The second control unit is used to maintain the predetermined droop parameter control if the frequency change does not exceed the second threshold, otherwise adopt the variable droop parameter control until the system frequency changes back to the frequency safety trajectory planning constraint and the control ends when entering a new steady state.

[0103] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0104] This embodiment also provides a computing device, which includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for optimizing energy storage frequency modulation of control parameters is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, trackball or touchpad set on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0105] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method proposed in the above embodiment is implemented.

[0106] The storage medium proposed in this embodiment and the method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0107] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0108] Example 2

[0109] Reference Figure 3 and Figure 6Based on the previous embodiment, this embodiment provides an application example of an energy storage frequency modulation method and system for optimizing control parameters, in order to verify and illustrate the technical effects adopted in this method.

[0110] Based on Matlab / Simulink simulation platform, Figure 3 The energy storage grid-connected system is shown to verify the feasibility and practicability of the present invention. Table 1 shows the main parameters of the simulation system.

[0111] Table 1: Main parameters of the simulation system.

[0112] parameter Numeric parameter Numeric <![CDATA[Bus voltage U dc / V]]> 1200 <![CDATA[R m / (Hz / s)]]> 2 <![CDATA[Rated frequency f N / Hz]]> 50 <![CDATA[ESS rated power P E / kW]]> 300 <![CDATA[F m / Hz]]> 0.5 <![CDATA[Disturbance ΔP1 / kW]]> 100 <![CDATA[f m / Hz]]> 0.4 <![CDATA[Disturbance ΔP2 / kW]]> 300

[0113] In this embodiment, the load is set to increase by 100kW at 15s and by 300kW at 20s. It is considered that the SOC of the ESS is sufficient. The total simulation time is 40s. Figure 6 The frequency characteristics of the system under conventional droop control and optimized parameter control are verified and compared as shown in the figure. When the load increases by 100kW at 15s, the frequency change rate R <R m , the frequency dropped by 0.25Hz (Δf <f m ), which is within the preset safety range of frequency modulation control. Therefore, the ESS maintains the original control when the system encounters a 100kW disturbance. At 20s, the system encounters a 0.3MW disturbance again, and the frequency change rate R <R m If the ESS still maintains the original control mode, the lowest point of the grid frequency will drop to 49.33Hz, at which time Δf>F m , exceeding the frequency safety domain specified by the power grid. Therefore, when the power grid frequency drops to 49.6Hz (i.e. Δf=f m ), variable droop control coefficient K p K p1 , ESS immediately increased the released power rapidly according to the planned trajectory, suppressed the frequency fluctuation, and the lowest frequency point was pulled back to 49.53Hz.

[0114] From the above, it can be seen that the energy storage frequency regulation method with optimized control parameters provided by the present invention makes up for the defect that the traditional generator set responds slowly and cannot provide fast and sufficient frequency regulation power, and improves the frequency regulation range and frequency regulation efficiency on the power generation side; compared with the traditional droop control, the present invention can directly increase the additional power to support frequency recovery, can quickly and effectively make corresponding decisions on system disturbances, and continue to use droop control within the safe and stable trajectory of frequency recovery to maximize the saving of frequency regulation resources; compared with the traditional direct power control, the present invention sets the frequency change rate R m and frequency change f mThese two thresholds can be used to plan the frequency safety trajectory under the disturbance, and reasonable decisions on energy storage output can be made through conditional judgment, which can avoid frequent charging and discharging of energy storage, which can not only optimize the efficiency of energy storage output, but also increase the service life of energy storage.

[0115] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. 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.

[0116] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0117] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0118] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0119] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0120] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0121] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for optimizing control parameters for energy storage frequency modulation, characterized in that: include: Set the FM dead zone and monitor the frequency in real time; When the frequency fluctuation exceeds the frequency modulation dead zone, disturbance estimation is performed and relevant parameters are calculated; Based on the relevant parameters, a frequency safety trajectory planning constraint is constructed in combination with a first frequency critical indicator; If the frequency fluctuation exceeds the first threshold, fast power control is performed to make the frequency change trajectory return to the frequency safety trajectory planning constraint, otherwise the frequency change amount is judged; If the frequency change does not exceed the second threshold, the predetermined droop parameter is maintained for control, otherwise the variable droop parameter is used for control until the system frequency changes back to the frequency safety trajectory planning constraint and the control ends when entering a new steady state.

2. The energy storage frequency modulation method for optimizing control parameters according to claim 1, characterized in that: The performing disturbance estimation when the frequency fluctuation exceeds the frequency modulation dead zone includes: When the frequency fluctuation exceeds the FM dead zone f N ±f0, record the frequency and frequency change rate at the initial disturbance time t1, and record the frequency and frequency change rate at t2 after the first time interval, and then the energy storage power station excitation small signal P E , after a delay of a second time interval, recording the frequency and the frequency change rate at time t3, wherein the range setting of the frequency modulation dead zone is affected by the normal frequency fluctuation required by the power load; Substitute the recorded frequencies and frequency change rates at time t1, t2, and t3 into the system frequency change equation for disturbance prediction. The formula is expressed as follows: Where H0 represents the system inertia, f represents the system frequency, K L Indicates load unit regulation power, f N Indicates the grid frequency, ΔP L Indicates the size of the disturbance.

3. The energy storage frequency modulation method for optimizing control parameters according to claim 2, characterized in that: include: Perform conditional judgment on the frequency change rate at the initial stage of disturbance occurrence according to the first threshold; If the frequency change rate at the initial stage of the disturbance exceeds the first threshold, fast power control is performed, and the droop control parameter K is P Change to K Pm ; Directly output power P through the energy storage power station C To quickly offset the impact of the disturbance on the system, that is, the energy storage output directly changes the frequency change rate and the final value of the frequency change at the initial stage of the disturbance, so that the frequency change trajectory returns to the frequency safety trajectory planning constraint; When the frequency change trajectory returns to the frequency safety trajectory planning constraint, the droop control parameter K Pm Then switch back to K P , continue to use droop control.

4. The energy storage frequency modulation method for optimizing control parameters according to claim 3, characterized in that: include: If the frequency change rate at the initial stage of the disturbance does not exceed the first threshold, determining the frequency change amount; If the frequency change does not exceed the second threshold, the predetermined droop control parameter K is maintained. P Control is performed, wherein the predetermined droop control parameter K P The second threshold is set according to the actual energy storage output planning requirements, and in principle does not exceed the frequency change threshold set according to the power grid requirements; If the frequency variation exceeds the second threshold, variable droop parameter control is adopted, and the droop control parameter K is set to P Change to K P1 , until the system frequency changes back to the frequency safety trajectory planning constraint. After the system frequency changes back to the frequency safety trajectory planning constraint, K P1 Return to the droop control parameter K P , the control ends when entering a new steady state.

5. The energy storage frequency modulation method for optimizing control parameters according to claim 4, characterized in that: When the frequency change rate exceeds the first threshold at the initial stage of the disturbance, fast power control is performed. At this time, the droop control parameter K PC and energy storage output P C The calculation is: P C =|ΔP L |-R m H0 Among them, R m represents the first threshold, F m Indicates the frequency change threshold that the power grid requires to be set.

6. The energy storage frequency modulation method for optimizing control parameters according to claim 2, characterized in that: The calculation-related parameters include: Among them, f1 and R1 represent the frequency and frequency change rate at the initial moment t1 of the disturbance, f2 and R2 represent the frequency and frequency change rate at the moment t2, and f3 and R3 represent the frequency and frequency change rate at the moment t3.

7. The energy storage frequency modulation method for optimizing control parameters according to claim 6, characterized in that: The construction frequency safety trajectory planning constraints include: Based on the disturbance size ΔP L , system inertia H0, load unit adjustment power K L , Droop control parameter K P , and combined with the first frequency critical index to construct the frequency safety trajectory planning constraint, the frequency safety trajectory range critical curve equation is:

8. A system using the energy storage frequency modulation method for optimizing control parameters as claimed in any one of claims 1 to 7, characterized in that: include: Frequency monitoring unit, used to set the frequency modulation dead zone and monitor the frequency in real time; A disturbance prediction unit, used for predicting disturbances and calculating relevant parameters when the frequency fluctuation exceeds the frequency modulation dead zone; A constraint construction unit, configured to construct a frequency safety trajectory planning constraint based on the relevant parameters and in combination with a first frequency critical indicator; A first control unit is used to perform rapid power control to make the frequency change trajectory return to the frequency safety trajectory planning constraint when the frequency fluctuation exceeds a first threshold, otherwise, to judge the frequency change amount; The second control unit is used to maintain the predetermined droop parameter control if the frequency change does not exceed the second threshold, otherwise adopt the variable droop parameter control until the system frequency changes back to the frequency safety trajectory planning constraint and the control ends when entering a new steady state.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having computer program instructions stored thereon, wherein the computer-executable instructions, when executed by a processor, implement the steps of the method according to any one of claims 1 to 7.

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