A control method and system for frequency modulation of a grid-side energy storage power station

Abstract

The application discloses a kind of power grid side energy storage power station frequency modulation control method and system, the method includes: in primary frequency modulation process, when receiving secondary frequency modulation instruction, the direction and power size of secondary frequency modulation and primary frequency modulation are compared, then the frequency modulation strategy is determined according to the result of the comparison.The application is applied to the energy storage field, avoids the interlock between primary frequency modulation and secondary frequency modulation of the same energy storage station in different regulation modes, to avoid the conflict of primary frequency modulation and secondary frequency modulation, while also can reduce the regulation time of energy storage power station, improves the stability of power system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optimal operation of energy storage power stations, and particularly relates to a control method and system for frequency modulation of a grid-side energy storage power station. BACKGROUND

[0002] As a new energy service product, energy storage is a high-quality and reliable millisecond-level control response resource that can provide dual support of active and reactive power and provide peak regulation, frequency modulation, backup, and emergency response services for power grids. In order to alleviate the power supply pressure during the summer peak period, improve the local power grid renewable energy consumption level, peak shaving and valley filling capacity, local power supply capacity, and power grid flexible regulation capacity, and combine the advantages of short construction period and flexible site of electrochemical energy storage power stations, a large number of grid-side energy storage power station projects have been deployed and implemented in China.

[0003] The grid-side energy storage power station is equipped with a primary frequency modulation and a secondary frequency modulation frequency modulation technical solution. The primary frequency modulation refers to the frequency regulation realized by the power station frequency modulation device system. When the grid frequency changes, the control system of the frequency modulation device detects the change and automatically adjusts the charge and discharge capacity of the energy storage power station to balance the imbalance between the power system load and the power source. The secondary frequency modulation is frequency regulation by dispatch of the power market, and the energy management system (EMS) of the energy storage station configures the station end to automatically adjust the charge and discharge capacity of the energy storage power station. In order to ensure that the primary frequency modulation (local mode) and the secondary frequency modulation (remote control) do not affect each other, the priority of the primary frequency modulation is higher than that of the secondary frequency modulation. When the primary frequency modulation is closed, the secondary frequency modulation of the energy management system (EMS) is locked, and after the primary frequency modulation is completed and the lock point is returned, the EMS energy management system can perform secondary frequency modulation. The secondary frequency modulation system can only wait, and the short adjustment of the primary frequency modulation cannot maintain the grid frequency unchanged. SUMMARY

[0004] (I) Invention purpose

[0005] The purpose of the present application is to provide a control method and system for frequency modulation of a grid-side energy storage power station. The method does not need to consider the priority of primary frequency modulation and secondary frequency modulation. When the primary frequency modulation is applied, the secondary frequency modulation is not locked. The strategy of the secondary frequency modulation is determined according to the direction and size of the AGC (automatic generation control system) instruction active power issued by the dispatch and whether the primary frequency modulation is consistent with the conditions, which can avoid the conflict between the primary frequency modulation and the secondary frequency modulation, and also can reduce the adjustment time of the energy storage power station.

[0006] (II) Technical solution

[0007] To solve the above problems, the first aspect of the present application provides a control method for frequency modulation of a grid-side energy storage power station, comprising:

[0008] The frequency modulation includes primary frequency modulation and secondary frequency modulation, and the control method includes:

[0009] In the primary frequency modulation process, when a secondary frequency modulation instruction is received, the direction and power size of the secondary frequency modulation and the primary frequency modulation are compared;

[0010] A frequency modulation strategy is determined according to a comparison result, including:

[0011] If the direction of the secondary frequency modulation is consistent with that of the primary frequency modulation, the active power of the secondary frequency modulation and the active power of the primary frequency modulation are compared, and a corresponding step instruction is issued according to the power size; the direction includes two states of charging direction and discharging direction, and charging is defined as negative and discharging as positive.

[0012] If the direction of the secondary frequency modulation is inconsistent with that of the primary frequency modulation, the primary frequency modulation signal is issued to the energy storage power station PCS to perform charging and discharging according to the primary frequency modulation priority principle.

[0013] Further, the comparison of the active power of the secondary frequency modulation and the active power of the primary frequency modulation according to the power size to determine the corresponding step instruction includes:

[0014] If the discharging step P21 is greater than the first active power P1, and P21-P1<ΔP, the AGC instruction adopts P21 for execution;

[0015] If the charging step P22 is less than the first active power P1, and |P22-P1|<ΔP, the AGC instruction adopts P22 for execution; wherein the power of the primary frequency modulation is the first active power P1, the active power of the secondary frequency modulation under the AGC instruction includes P21 and P22, and P21 and P22 are the discharging step and the charging step respectively.

[0016] Further, the control method further includes that, in the charging and discharging process, if a new AGC instruction of the secondary frequency modulation is received, the new AGC instruction is compared with the direction and power size of the primary frequency modulation to determine the frequency modulation strategy, and the process is circularly executed.

[0017] Further, the secondary frequency modulation can also control the PCS of the energy storage power station to perform charging and discharging.

[0018] The second aspect of the present application provides a control system for grid-side energy storage power station frequency modulation, the frequency modulation including primary frequency modulation and secondary frequency modulation, and the system includes:

[0019] A comparison module is configured to compare the direction and power size of the secondary frequency modulation and the primary frequency modulation when a secondary frequency modulation instruction is received in the primary frequency modulation process;

[0020] A frequency modulation module is configured to determine a frequency modulation strategy according to a comparison result, including:

[0021] The first judging submodule is configured to compare the active power of the secondary frequency modulation with the active power of the primary frequency modulation if the directions of the secondary frequency modulation and the primary frequency modulation are consistent, and determine a corresponding step instruction according to the power size.

[0022] The second judging submodule is configured to, if the directions of the secondary frequency modulation and the primary frequency modulation are inconsistent, according to the principle of primary frequency modulation priority, issue the primary frequency modulation signal to the energy storage power station PCS to perform charging and discharging.

[0023] Further, the first judging submodule is specifically configured to:

[0024] If the discharging step P21 is greater than the first active power P1, and P21-P1<ΔP, the AGC instruction adopts P21 to execute.

[0025] If the charging step P22 is less than the first active power P1, and |P22-P1|<ΔP, the AGC instruction adopts P22 to execute; wherein the power of the primary frequency modulation is the first active power P1, the active power of the secondary frequency modulation under the AGC instruction includes P21 and P22, and P21 and P22 are respectively the discharging step and the charging step.

[0026] Further, the system further comprises a circulation module configured to, in the process of charging and discharging, if a new AGC instruction of the secondary frequency modulation is received, compare the new AGC instruction with the direction and power size of the primary frequency modulation to determine the frequency modulation strategy, and thus circulate and operate.

[0027] (Three) beneficial effects

[0028] The technical scheme of the present application has the following beneficial technical effects: the present application provides a control method and system for frequency modulation of a grid-side energy storage power station, which is mainly applied in the field of energy storage, and avoids the blocking between primary frequency modulation and secondary frequency modulation of the same energy storage station in different adjustment modes. The design principle is as follows: when a signal of primary frequency modulation is generated, the energy management system (EMS) detects whether secondary frequency modulation is in action, and the energy management system (EMS) detects in real time whether a new adjustment instruction of active power is received or whether AGC active power adjustment is being performed. If not, the energy management system does not execute any strategy. If a new adjustment instruction of active power is detected or AGC active power adjustment is being performed, the direction and power size of secondary frequency modulation and primary frequency modulation are compared, and then the corresponding execution strategy of secondary frequency modulation is determined. If the direction of secondary frequency modulation and primary frequency modulation is consistent, the active power of secondary frequency modulation and the active power of primary frequency modulation are compared, and the corresponding step instruction is issued according to the power size. If the direction of secondary frequency modulation and primary frequency modulation is inconsistent, the primary frequency modulation signal is issued to the energy storage power station PCS to perform charging and discharging according to the principle of primary frequency modulation priority. The present application determines the frequency modulation strategy according to the comparison result to avoid the conflict between primary frequency modulation and secondary frequency modulation, and also reduces the adjustment time of the energy storage power station and improves the stability of the power system. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a flowchart of a control method for frequency modulation of a grid-side energy storage power station of the present application;

[0030] Figure 2 is a flowchart of a control method for frequency modulation of a grid-side energy storage power station of an embodiment of the present application;

[0031] Figure 3 is a network structure diagram of joint adjustment of an embodiment of the present application;

[0032] Figure 4 is a schematic diagram of a control system for frequency modulation of a grid-side energy storage power station of the present application. DETAILED DESCRIPTION

[0033] To make the purpose, technical scheme and advantages of the present application clearer and more comprehensible, the present application is further described in detail below with reference to the specific embodiments and the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0034] As Figure 1As shown, one aspect of the present application provides a control method for grid-side energy storage power station frequency modulation, which does not need to consider the priority of primary frequency modulation and secondary frequency modulation, does not lock the secondary frequency modulation during primary frequency modulation, and determines the strategy of secondary frequency modulation according to the consistency of the direction and size of the AGC instruction active power and the primary frequency modulation, and specifically comprises:

[0035] S1, in the process of primary frequency modulation, when the secondary frequency modulation instruction is received, the direction and power size of the secondary frequency modulation and the primary frequency modulation are compared. When the signal of primary frequency modulation is generated, it is detected by the energy storage EMS whether the secondary frequency modulation is in action. The energy management system (EMS) collects the data changes of the primary frequency modulation device in real time, including the action state signal S and the adjustment power P1. When the action state signal S is in action, the adjustment power P1 also changes, which proves that the primary frequency modulation is adjusting, and the charging and discharging instructions are sent to the PCS (bidirectional converter). The action of secondary frequency modulation includes the new adjustment instruction of active power or the execution of AGC active power. 。 Under the AGC instruction, the active power of secondary frequency modulation includes P21 and P22, P21 and P22 are discharge step and charge step respectively. The power of primary frequency modulation is the first active power P1. When the signal of primary frequency modulation is generated, the energy management system detects in real time whether the new adjustment instruction of active power is received or the AGC active power is being executed 。 As shown in Figure 2 If the secondary frequency modulation is not in action, no strategy is executed. The energy management system detects in real time that no new adjustment instruction of active power is received or the AGC active power is being executed, and the energy management system does not execute any strategy. If the secondary frequency modulation is in action, the corresponding execution strategy is determined by comparing the direction and power size of the secondary frequency modulation and the primary frequency modulation. The direction includes two states of charging direction and discharging direction, and the charging is negative and the discharging is positive.

[0036] S2, the frequency modulation strategy is determined according to the comparison result, including:

[0037] S21, if the direction of secondary frequency modulation is consistent with that of primary frequency modulation, the active power of secondary frequency modulation is compared with the active power of primary frequency modulation, and the corresponding step instruction is issued according to the power size. When there is a new active power (P AGC ) adjustment instruction of AGC or the AGC active power (P AGC ) adjustment is being executed, the direction and size of the adjusted active power P1 are recorded. Including the following two cases:

[0038] (1) If the discharge step P21 is greater than the first active power P1, and P21-P1<ΔP, the AGC instruction adopts P21 to execute. Specifically: the current P21 and P1 are compared in direction, for example, the charging is negative and the discharging is positive. If the direction is the same, PAGC Each step P21>P1, and P21-P1<ΔP, ΔP is a power setting, which can be configured on site, and the change of ΔP is not enough to exceed the dead zone of the frequency detection device of the primary frequency modulation device, to ensure the infrequent action of the primary frequency modulation device, and the energy management system can execute the strategy, and implement the issuance of the strategy P21 (corresponding to Figure 2 P step in the discharge mode) to the energy storage converter (PCS), and the PCS completes the charging of the battery.

[0039] (2) If the charging step P22 is less than the first active power P1, and |P22-P1|<ΔP, the AGC instruction is executed by P22. AGC In the execution of the charging process, P22 is negative, P22 Figure 2 P1, |P22-P1|<ΔP, the energy management system also executes the strategy, and implements the issuance of the strategy P22 (corresponding to AGC the power regulation of the current period.

[0040] S22, if the directions of the secondary frequency modulation and the primary frequency modulation are inconsistent, the primary frequency modulation signal is issued to the energy storage power station PCS to execute charging and discharging according to the primary frequency modulation priority principle, and the active power P1 is executed. Specifically, if it is judged that the current P AGC is opposite to the direction of P1, when the local primary frequency modulation and the remote AGC (secondary frequency modulation) command are inconsistent, the local priority is high, the energy management system suspends the remote AGC, and the primary frequency modulation device completes the local frequency modulation processing first, and when the state signal S acts and returns, the energy management system continues to issue the AGC instruction, and performs the charging and discharging of the battery.

[0041] The control method further comprises S23: in the charging and discharging process, if a new AGC instruction of the secondary frequency modulation is received, then the direction and the power size of the new AGC instruction and the primary frequency modulation are compared to determine the frequency modulation strategy, and the cycle operation is performed. In the process of executing the above steps, the energy management system receives the new AGC instruction issued by the dispatch, replaces the old AGC instruction, and the energy management system executes the new AGC instruction to complete the charging and discharging of the battery. The secondary frequency modulation can also control the charging and discharging of the energy storage power station PCS. As shown in Figure 2 the directions of the secondary frequency modulation and the primary frequency modulation are consistent, in the discharge mode: if P21-P1≥ΔP, the AGC instruction executes the first active power P1; and in the charging mode: |P22-P1|≥ΔP, the AGC instruction executes the first active power P1. Figure 3 to jointly regulate the network structure. Figure 3In the prior art, both the primary frequency modulation and the secondary frequency modulation can send adjustment commands to the PCS to control the charging and discharging of the battery, wherein the frequency modulation device represents the primary frequency modulation, and the EMS represents the secondary frequency modulation.

[0042] As shown in Figure 4 the second aspect of the present application provides a control system for grid-side energy storage power station frequency modulation, comprising:

[0043] a comparison module 21 configured to compare the direction and power size of the secondary frequency modulation and the primary frequency modulation when the secondary frequency modulation instruction is received in the primary frequency modulation process;

[0044] a frequency modulation module 22 configured to determine a frequency modulation strategy according to the comparison result, comprising:

[0045] a first judgment sub-module 221 configured to compare the active power of the secondary frequency modulation and the active power of the primary frequency modulation if the direction of the secondary frequency modulation is consistent with the direction of the primary frequency modulation, and determine a corresponding step instruction according to the power size;

[0046] a second judgment sub-module 222 configured to, if the direction of the secondary frequency modulation is inconsistent with the direction of the primary frequency modulation, according to the primary frequency modulation priority principle, issue the primary frequency modulation signal to the energy storage power station PCS to perform charging and discharging.

[0047] Further, the first judgment sub-module 221 is specifically configured to:

[0048] if the discharging step P21 is greater than the first active power P1, and P21-P1<ΔP, then the AGC instruction adopts P21 for execution;

[0049] if the charging step P22 is less than the first active power P1, and |P22-P1|<ΔP, then the AGC instruction adopts P22 for execution; wherein the power of the primary frequency modulation is the first active power P1, the active power of the secondary frequency modulation under the AGC instruction includes P21 and P22, and P21 and P22 are the discharging step and the charging step, respectively.

[0050] Further, the system further comprises a loop module 23 configured to, in the charging and discharging process, if a new AGC instruction of the secondary frequency modulation is received, then determine a frequency modulation strategy after comparing the direction and power size of the new AGC instruction and the primary frequency modulation, and thus run in a loop.

[0051] The application aims to provide a grid-side energy storage power station frequency modulation control method and system. The method is a grid-side energy management system control strategy optimization method, mainly applied to the energy storage field. The application does not need to consider the priority of primary frequency modulation and secondary frequency modulation, and does not lock the secondary frequency modulation when the primary frequency modulation is performed. The strategy of the secondary frequency modulation is determined according to the conditions such as the consistency of the direction and size of the AGC instruction active power issued by the dispatch and the primary frequency modulation. In the method, when the signal of the primary frequency modulation is generated, whether the secondary frequency modulation is in action is detected by the energy storage EMS. If the new active power regulation instruction or the AGC active power regulation is being performed is detected, the corresponding execution strategy of the secondary frequency modulation is determined by comparing the direction and power size of the secondary frequency modulation and the primary frequency modulation, that is, two cases are included. In the first case, if the direction of the secondary frequency modulation is consistent with that of the primary frequency modulation, the active power of the secondary frequency modulation is compared with the active power of the primary frequency modulation. The power comparison process includes two cases. If the discharging step P21 is greater than the first active power P1, and P21-P1<ΔP, the AGC instruction adopts P21 for execution. If the charging step P22 is less than the first active power P1, and |P22-P1|<ΔP, the AGC instruction adopts P22 for execution. In the second case, if the direction of the secondary frequency modulation is inconsistent with that of the primary frequency modulation, the primary frequency modulation signal is issued to the energy storage power station PCS to perform charging and discharging according to the primary frequency modulation priority principle. Through the above design, the lock between the primary frequency modulation and the secondary frequency modulation in the same energy storage station in different adjustment modes can be avoided, the conflict between the primary frequency modulation and the secondary frequency modulation can be avoided, the adjustment time of the energy storage power station can be reduced, and the stability of the power system can be improved. The application has the following advantages.

[0052] 1) The method solves the mutual exclusion problem in the primary and secondary frequency modulation process of the energy storage power station. The energy management system strategy is greatly changed from only paying attention to the primary frequency modulation lock signal to not only paying attention to the lock signal but also participating in the secondary frequency modulation system.

[0053] 2) The method determines the corresponding strategy in the primary and secondary frequency modulation process by comparing the power direction and size, meets the user grid requirements, and improves the execution efficiency of the grid-side AGC.

[0054] It is to be understood that the above specific embodiments of the present application are merely illustrative of the principles of the present application and are not intended to limit the present application. Any modification, equivalent substitution, improvement, etc. made without departing from the spirit and scope of the present application should be included in the scope of protection of the present application. In addition, the appended claims of the present application are intended to cover all changes and modifications falling within the scope and boundary of the appended claims, or equivalents of such scope and boundary. The present application is described above with reference to the embodiments of the present application. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Those skilled in the art can make various substitutions and modifications without departing from the scope of the present application, and such substitutions and modifications should be included in the scope of the present application. Although the embodiments of the present application have been described in detail, it should be understood that various changes, substitutions and alterations can be made to the embodiments of the present application without departing from the spirit and scope of the present application. Obviously, the above-described embodiments are merely examples for clarity, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or modifications can be made by those skilled in the art. It is not necessary or possible to exhaust all embodiments. The obvious changes or modifications derived therefrom are still within the scope of protection of the present application. Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer usable program code. The present application is described with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams 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 apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowchart Figure 1 One or more flows and / or blocks Figure 1 One or more flows and / or blocks The computer program instructions can also be stored in a computer readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including instruction devices that implement the functions specified in the flowFigure 1 one or more processes and / or functions specified in the flow block or blocks. Figure 1 These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer implemented process, so that the instructions executed on the computer or other programmable data processing devices provide steps for implementing the function specified in the flow block or blocks. Figure 1 one or more processes and / or functions specified in the flow block or blocks. Figure 1 These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer implemented process, so that the instructions executed on the computer or other programmable data processing devices provide steps for implementing the function specified in the flow block or blocks.

[0055] A person of ordinary skill in the art can understand that all or part of the steps of the above-mentioned embodiment methods can be completed by programs instructing relevant hardware, and the programs can be stored in a computer readable storage medium. When the program is executed, the following processes of the above-mentioned embodiments of each method are included. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM) or a random access memory (RAM), etc. The steps in the embodiment methods of the present application can be adjusted, combined and reduced in sequence according to actual needs. The modules in the embodiment system of the present application (terminal or device) can be combined, divided and reduced according to actual needs.

Claims

1. A control method for frequency regulation of a grid-side energy storage power station, characterized in that, The frequency modulation includes primary frequency modulation and secondary frequency modulation, and the control method includes: During the primary frequency modulation process, when a secondary frequency modulation command is received, the direction and power magnitude of the secondary frequency modulation are compared with those of the primary frequency modulation. Determining the frequency modulation strategy based on the comparison results includes: If the secondary frequency modulation and the primary frequency modulation are in the same direction, the active power of the secondary frequency modulation is compared with the active power of the primary frequency modulation. Based on the power magnitude, a corresponding step size command is issued, including: if the discharge step size P21 > the first active power P1, and P21 - P1 < ... If P, then the AGC instruction is executed using P21; if the charging step size P22 < the first active power P1, and |P22-P1| < If P is selected, the AGC command will be executed using P22. The power for primary frequency regulation is the first active power P1. Under the AGC command, the active power for secondary frequency regulation includes P21 and P22, where P21 and P22 are the discharge step size and charging step size, respectively. P is a power constant; If the directions of secondary frequency regulation and primary frequency regulation are inconsistent, the primary frequency regulation signal will be sent to the energy storage power station PCS to perform charging and discharging according to the principle of primary frequency regulation priority.

2. The control method for frequency regulation of a grid-side energy storage power station according to claim 1, characterized in that, The control method further includes: During the charging and discharging process, if a new AGC command for secondary frequency modulation is received, the new AGC command is compared with the direction and power of the primary frequency modulation to determine the frequency modulation strategy, and this process is repeated cyclically.

3. The control method for frequency regulation of a grid-side energy storage power station according to claim 1, characterized in that, The secondary frequency modulation can also control the charging and discharging of the energy storage power station PCS.

4. A control system for frequency regulation of a grid-side energy storage power station, characterized in that, The frequency modulation includes primary frequency modulation and secondary frequency modulation, and the system includes: The comparison module is used to compare the direction and power of the secondary frequency modulation with that of the primary frequency modulation when a secondary frequency modulation command is received during the primary frequency modulation process. A frequency modulation module, used to determine a frequency modulation strategy based on the comparison result, includes: The first judgment submodule is used to compare the active power of the secondary frequency modulation with that of the primary frequency modulation if the directions of the secondary frequency modulation and the primary frequency modulation are consistent, and determine the corresponding step size instruction to be issued based on the power magnitude; specifically, the first judgment submodule is used to: if the discharge step size P21 > the first active power P1, and P21 - P1 < If P is the first active power, then the AGC instruction is executed using P21; if the charging step size P22 < the first active power P1, and |P22 - P1| < P22, then the AGC instruction is executed using P21. If P is used, the AGC command is executed using P22; the power of the first frequency regulation is the first active power P1. Under the AGC command, the active power of the second frequency regulation includes P21 and P22, where P21 and P22 are the discharge step size and the charging step size, respectively. The second judgment submodule is used to send the primary frequency modulation signal to the energy storage power station PCS to perform charging and discharging if the directions of the secondary frequency modulation and the primary frequency modulation are inconsistent, according to the primary frequency modulation priority principle.

5. The control system for frequency regulation of the grid-side energy storage power station according to claim 4, characterized in that, The system also includes a loop module, which, during the charging and discharging process, if a new AGC command for secondary frequency modulation is received, compares the new AGC command with the direction and power of primary frequency modulation to determine the frequency modulation strategy, and then runs in a loop.

Images